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Sample records for bismuth film electrode

  1. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE)

    Science.gov (United States)

    Dossi, Carlo; Monticelli, Damiano; Pozzi, Andrea; Recchia, Sandro

    2016-01-01

    Mercury substitution is a big issue in electroanalysis, and the search for a suitable, and less toxic, replacement is still under development. Of all the proposed alternatives, bismuth films appear to be the most viable solution, although they are still suffering some drawbacks, particularly the influence of deposition conditions and linearity at low concentrations. In this paper, the most promising strategies for bismuth film deposition on screen-printed electrodes (surface modifications, polymeric film deposition, insoluble salt precursors) will be evaluated for trace metal analysis. Particular attention will be devoted to bismuth chemistry, aiming to rationalize their electroanalytic performance. PMID:27455338

  2. Exploiting Chemistry to Improve Performance of Screen-Printed, Bismuth Film Electrodes (SP-BiFE

    Directory of Open Access Journals (Sweden)

    Carlo Dossi

    2016-07-01

    Full Text Available Mercury substitution is a big issue in electroanalysis, and the search for a suitable, and less toxic, replacement is still under development. Of all the proposed alternatives, bismuth films appear to be the most viable solution, although they are still suffering some drawbacks, particularly the influence of deposition conditions and linearity at low concentrations. In this paper, the most promising strategies for bismuth film deposition on screen-printed electrodes (surface modifications, polymeric film deposition, insoluble salt precursors will be evaluated for trace metal analysis. Particular attention will be devoted to bismuth chemistry, aiming to rationalize their electroanalytic performance.

  3. Use of hydrogen peroxide to achieve interference-free stripping voltammetric determination of copper at the bismuth-film electrode

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Wagner F.; Miguel, Eliane M.; Ramos, Gabriel V. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro (PUC-RJ), Rio de Janeiro, RJ 22451-900 (Brazil); Cardoso, Carlos E. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro (PUC-RJ), Rio de Janeiro, RJ 22451-900 (Brazil); Natural and Technological Science Center, Universidade Severino Sombra, Vassouras, RJ 27700-000 (Brazil); Farias, Percio A.M. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro (PUC-RJ), Rio de Janeiro, RJ 22451-900 (Brazil); Aucelio, Ricardo Q. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro (PUC-RJ), Rio de Janeiro, RJ 22451-900 (Brazil)], E-mail: aucelior@rdc.puc-rio.br

    2008-09-05

    In this work, a new approach is presented to allow interference-free determination of Cu (II) by stripping voltammetry using the bismuth-film electrode. The addition of hydrogen peroxide to the electroanalytical cell has promoted complete resolution between re-dissolution peaks of Bi (III) and Cu (II). The absence of interference could be evaluated by the correlation coefficient (r > 0.99) between Cu (II) concentration and its shifted current peak (at +212 mV) while achieving a slightly fluctuation of the bismuth current peak at -180 mV. Studies were performed aiming towards the optimum conditions for trace determination of Cu (II) using hydrogen peroxide. The methodology was applied to a real sample (sugarcane spirits) and the results were compared to those from graphite furnace atomic absorption spectrometry. The analytical parameters of merit and the results of the analysis indicated that the analytical methodology could be readily used for trace determination of Cu (II)

  4. Lab-on-a-Chip Sensor with Evaporated Bismuth Film Electrode for Anodic Stripping Voltammetry of Zinc

    Science.gov (United States)

    Kang, Wenjing; Pei, Xing; Yue, Wei; Bange, Adam; Heineman, William R.; Papautsky, Ian

    2013-01-01

    In this work, we report on the development of a lab-on-a-chip electrochemical sensor that uses an evaporated bismuth electrode to detect zinc using square wave anodic stripping voltammetry. The microscale electrochemical cell consists of a bismuth working electrode, an integrated silver/silver chloride reference electrode, and a gold auxiliary electrode. The sensor demonstrated linear response in 0.1 M acetate buffer at pH 6 with zinc concentrations ranging from 1 μM to 30 μM and a calculated detection limit of 60 nM. The sensor was also able to successfully detect zinc in a bovine serum extract and the results were verified with independent AAS measurements. These results demonstrate the advantageous qualities of this lab-on-a-chip electrochemical sensor for clinical applications, which include a small sample volume (μL scale), reduced cost, short response time and high accuracy at low concentrations of analyte. PMID:24436575

  5. Graphene ultrathin film electrodes modified with bismuth nanoparticles and polyaniline porous layers for detection of lead and cadmium ions in acetate buffer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaomeng; Li, Lin; Liu, Erjia, E-mail: mejliu@ntu.edu.sg

    2013-10-01

    Graphene ultrathin films were synthesized by means of solid-state carbon diffusion from amorphous carbon (a-C) thin layers deposited on silicon substrates, which was catalyzed by nickel layers coated on the top of the a-C layers. The graphene films were used as working electrodes that were modified by a polyaniline (PANI) porous layer together with in-situ deposited bismuth (Bi) nanoparticles for the detection of trace heavy metal ions (Pb{sup 2+} and Cd{sup 2+}) in acetate buffer solutions (pH 5.3) with square wave anodic stripping voltammetry. The graphene electrodes modified with PANI porous layers and Bi nanoparticles had excellent repeatability, ultrahigh sensitivity (as low as 0.33 nM) and good resistance to passivation caused by the surface active species adsorbed on the electrode surfaces. - Highlights: • Graphene fabricated by nickel-catalyzed carbon diffusion in solid state • Graphene electrodes modified by bismuth nanoparticles and polyaniline layers • High resistance of modified graphene electrodes to passivation in acetate solutions • Ultra-low detection limits of lead and cadmium ions by modified graphene electrodes.

  6. Preparation of dendritic bismuth film electrodes and their application for detection of trace Pb (II) and Cd (II)

    Institute of Scientific and Technical Information of China (English)

    Huizhu Zhou; Huanhuan Hou; Lei Dai; Yuehua Li; Jing Zhu; Ling Wang

    2016-01-01

    In this paper, dendritic Bi film electrodes with porous structure had successfully been prepared on glassy carbon electrode using a constant current electrolysis method based on hydrogen bubble dynamic templates. The elec-trode prepared using a large applied current density showed an increased internal electroactive area and a signif-icantly improved electrochemical performance. The analytical utility of the prepared dendritic Bi film electrodes for the determination of Pb (II) and Cd (II) in the range of 5–50μg·L−1 were presented in combination with square wave stripping voltammetry in model solution. Compared with non-porous Bi film electrode, the dendrit-ic Bi film electrode exhibited higher sensitivity and lower detection limit. The prepared Bi film electrode with dendritic structure was also successfully applied to real water sample analysis.

  7. Electrochemical properties of porous bismuth electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Romann, T., E-mail: tavo.romann@ut.e [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Lust, E. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia)

    2010-08-01

    The properties of Bi surfaces with different roughnesses were characterized by electron microscopy, cyclic voltammetry, and impedance spectroscopy. Two different strategies were used for preparation of porous bismuth layers onto Bi microelectrode surface in aqueous 0.1 M LiClO{sub 4} solution. Firstly, treatment at potential E < -2 V (vs. Ag|AgCl in sat. KCl) has been applied, resulting in bismuth hydride formation and decomposition into Bi nanoparticles which deposit at the electrode surface. Secondly, porous Bi layer was prepared by anodic dissolution (E = 1 V) of bismuth electrode followed by fast electroreduction of formed Bi{sup 3+} ions at cathodic potentials E = -2 V. The nanostructured porous bismuth electrode, with surface roughness factor up to 220, has negligible frequency dispersion of capacitance and higher hydrogen evolution overvoltage than observed for smooth Bi electrodes.

  8. Electrocatalytic activity of bismuth doped silver electrodes

    CERN Document Server

    Amjad, M

    2002-01-01

    Investigation of redox reactions on silver, and bismuth doped silver electrodes in aqueous KOH solutions, by using potentiostatic steady-state polarization technique, has been carried out. The redox wave potential and current displacements along with multiplicity of the latter have been examined. These electrodes were employed for the oxidation of organic molecules such as ethylamine in alkaline media. Subsequently, these electrodes were ranked with respect to their activity for the redox reactions. (author)

  9. Electroanalysis of organic compounds at bismuth electrodes: a short review

    OpenAIRE

    Lezi, Nikolitsa; Vyskočil, Vlastimil; Economou, Anastasios; Barek, Jiří

    2012-01-01

    Over the last twelve years, it has been demonstrated that bismuth electrodes have comparable electroanalytical performance to mercury electrodes in the negative potential range. Since the toxicicty of bismuth is lower than that of mercury, bismuth can serve as an alternative “green” electrode material to mercury. However, the great majority of published work at bismuth–based electrodes is concerned with the determination of trace metals by voltammetric techniques with only few applications de...

  10. Bismuth electrodes, an alternative in stripping voltammetry

    International Nuclear Information System (INIS)

    The heavy metals are known as highly toxic contaminants, the processes carried out in industry contribute that finally they remain dispersed in effluents and sewage, doing part of the food chain. The importance of controlling the levels of these heavy metals has become an international policy, so it has generated interest in developing new analytical methodologies for its determination [1, 2, 3, 4]. The stripping voltammetry has been considered as a family of electro-sensitive analytical techniques useful for the determination of trace levels of many metals in environmental, clinical and industrial samples [3, 4]. This work presents an overview of these bismuth-based electrodes which were introduced around 2000, which have interesting characteristics for detection of heavy metals and which represent an alternative to mercury electrodes

  11. Bismuth electrodes, an alternative in stripping voltammetry

    Science.gov (United States)

    Barón-Jaimez, J.; Joya, M. R.; Barba-Ortega, J.

    2013-11-01

    The heavy metals are known as highly toxic contaminants, the processes carried out in industry contribute that finally they remain dispersed in effluents and sewage, doing part of the food chain. The importance of controlling the levels of these heavy metals has become an international policy, so it has generated interest in developing new analytical methodologies for its determination [1, 2, 3, 4]. The stripping voltammetry has been considered as a family of electro-sensitive analytical techniques useful for the determination of trace levels of many metals in environmental, clinical and industrial samples [3, 4]. This work presents an overview of these bismuth-based electrodes which were introduced around 2000, which have interesting characteristics for detection of heavy metals and which represent an alternative to mercury electrodes.

  12. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    International Nuclear Information System (INIS)

    Bismuth vanadate, Bi4V2O11, and related compounds with various metal (Me) substitutions, Bi4(MexV1−x)2O11−δ, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated

  13. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    Energy Technology Data Exchange (ETDEWEB)

    Exner, Jörg, E-mail: Functional.Materials@Uni-Bayreuth.de [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany); Fuierer, Paul [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Moos, Ralf [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany)

    2014-12-31

    Bismuth vanadate, Bi{sub 4}V{sub 2}O{sub 11}, and related compounds with various metal (Me) substitutions, Bi{sub 4}(Me{sub x}V{sub 1−x}){sub 2}O{sub 11−δ}, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated.

  14. Bismuth Modified Carbon-Based Electrodes for the Determination of Selected Neonicotinoid Insecticides

    OpenAIRE

    Marko Rodić; Olga Vajdle; Valéria Guzsvány; Jasmina Zbiljić; Zsigmond Papp

    2011-01-01

    Two types of bismuth modified electrodes, a bismuth-film modified glassy carbon (BiF-GCE) and a bismuth bulk modified carbon paste, were applied for the determination of selected nitroguanidine neonicotinoid insecticides. The method based on an ex situ prepared BiF-GCE operated in the differential pulse voltammetric (DPV) mode was applied to determine clothianidin in the concentration range from 2.5 to 23 μg cm−3 with a relative standard deviation (RSD) not exceeding 1.5%. The tricresyl phosp...

  15. Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode.

    Science.gov (United States)

    Lee, Gyoung-Ja; Kim, Chang Kyu; Lee, Min Ku; Rhee, Chang Kyu

    2010-12-15

    Effect of phase stability degradation of bismuth on sensor characteristics of nano-bismuth fixed electrode has been investigated using square-wave anodic stripping voltammetry technique, scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectroscopy. From the analyses of square-wave anodic stripping voltammograms (SWASV) repetitively measured on the nano-bismuth fixed electrode, it was found that the oxidation peak currents dropped by 81%, 68% and 59% for zinc, cadmium and lead, respectively, after the 100th measurement (about 400 min of operation time). The sphere bismuth nanoparticles gradually changed to the agglomerates with petal shape as the operation time increased. From the analyses of SEM images and XRD patterns, it is confirmed that the oxidation of Bi into BiOCl/Bi(2)O(2)CO(3) and the agglomeration of bismuth nanoparticles caused by the phase change decrease a reproducibility of the stripping voltammetric response. Moreover, most of the bismuth becomes BiOCl at pH 3.0 and bismuth hydroxide, Bi(OH)(3) at pH 7.0, which results in a significant decrease in sensitivity of the nano-bismuth fixed electrode.

  16. Bismuth Modified Carbon-Based Electrodes for the Determination of Selected Neonicotinoid Insecticides

    Directory of Open Access Journals (Sweden)

    Marko Rodić

    2011-05-01

    Full Text Available Two types of bismuth modified electrodes, a bismuth-film modified glassy carbon (BiF-GCE and a bismuth bulk modified carbon paste, were applied for the determination of selected nitroguanidine neonicotinoid insecticides. The method based on an ex situ prepared BiF-GCE operated in the differential pulse voltammetric (DPV mode was applied to determine clothianidin in the concentration range from 2.5 to 23 μg cm−3 with a relative standard deviation (RSD not exceeding 1.5%. The tricresyl phosphate-based carbon paste electrodes (TCP-CPEs, bulk modified with 5 and 20 w/w% of bismuth, showed a different analytical performance in the determination of imidacloprid, regarding the peak shape, potential window, and noise level. The TCP-CPE with 5% Bi was advantageous, and the developed DPV method based on it allowed the determination in the concentration range from 1.7 to 60 μg cm−3 with an RSD of 2.4%. To get a deeper insight into the morphology of the bismuth-based sensor surfaces, scanning electron microscopic measurements were performed of both the surface film and the bulk modified electrodes.

  17. Electrodeposition of bismuth telluride thermoelectric films from a nonaqueous electrolyte using ethylene glycol

    NARCIS (Netherlands)

    Nguyen, H.P.; Wu, M.; Su, J.; Vullers, R.J.M.; Vereecken, P.M.; Fransaer, J.

    2012-01-01

    Ethylene glycol was studied as an electrolyte for the electrodeposition of thermoelectric bismuth telluride films by cyclic voltammetry, rotating ring disk electrode and electrochemical quartz crystal microbalance (EQCM). The reduction of both Bi3+ and Te4+ ions proceeds in one step without the form

  18. Inexpensive laser-induced surface modification in bismuth thin films

    International Nuclear Information System (INIS)

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD–DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters

  19. Inexpensive laser-induced surface modification in bismuth thin films

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, A. Reyes [Facultad de Ciencias, Universidad Autónoma del Estado de México, Carretera Toluca, Ixtlahuaca Kilómetro 15.5, C.P. 50200 Edo. de México (Mexico); Hautefeuille, M., E-mail: mathieu_h@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Circuito Exterior S/N, Coyoacán, Ciudad Universitaria, C.P. 04510 D.F. Mexico (Mexico); García, A. Esparza [Fotofísica y Películas Delgadas, Departamento de Tecnociencias, CCADET-UNAM, Circuito exterior s/n C.P. 04510 Cd. Universitaria, D.F. Mexico (Mexico); Mejia, O. Olea [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, Km 14.5, Unidad El Rosedal, 50200 San Cayetano, Estado de México (Mexico); López, M.A. Camacho [Facultad de Química, Universidad Autónoma del Estado de México, Tollocan s/n, esq. Paseo Colón, Toluca, Estado de México 50110 (Mexico)

    2015-05-01

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD–DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters.

  20. Bismuth(III) dialkyldithiophosphates: Facile single source precursors for the preparation of bismuth sulfide nanorods and bismuth phosphate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, Jasmine B. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Garje, Shivram S., E-mail: ssgarje@chem.mu.ac.in [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Nuwad, Jitendra; Pillai, C.G.S. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2013-08-15

    Two different phase pure materials (Bi{sub 2}S{sub 3} and Bi{sub 2}P{sub 4}O{sub 13}) have been prepared under different conditions using the same single source precursors. Solvothermal decomposition of the complexes, Bi(S{sub 2}P(OR){sub 2}){sub 3} [where, R=Methyl (Me) (1), Ethyl (Et) (2), n-Propyl (Pr{sup n}) (3) and iso-Propyl (Pr{sup i}) (4)] in ethylene glycol gave orthorhombic bismuth sulfide nanorods, whereas aerosol assisted chemical vapor deposition (AACVD) of the same precursors deposited monoclinic bismuth tetraphosphate (Bi{sub 2}P{sub 4}O{sub 13}) thin films on glass substrates. Surface study of the thin films using SEM illustrated the formation of variety of nanoscale morphologies (spherical-, wire-, pendent-, doughnut- and flower-like) at different temperatures. AFM studies were carried out to evaluate quality of the films in terms of uniformity and roughness. Thin films of average roughness as low as 1.4 nm were deposited using these precursors. Photoluminescence studies of Bi{sub 2}P{sub 4}O{sub 13} thin films were also carried out. - Graphical abstract: Solvothermal decomposition of bismuth(III) dialkyldithiophosphates in ethylene glycol gave Bi{sub 2}S{sub 3} nanoparticles, whereas aerosol assisted chemical vapor deposition of these single source precursors deposited Bi{sub 2}P{sub 4}O{sub 13} thin films. Display Omitted - Highlights: • Preparation of phase pure orthorhombic Bi{sub 2}S{sub 3} nanorods and monoclinic Bi{sub 2}P{sub 4}O{sub 13} thin films. • Use of single source precursors for deposition of bismuth phosphate thin films. • Use of solvothermal decomposition and AACVD methods. • Morphology controlled synthesis of Bi{sub 2}P{sub 4}O{sub 13} thin films. • Bi{sub 2}S{sub 3} nanorods and Bi{sub 2}P{sub 4}O{sub 13} thin films using same single source precursors.

  1. Facile preparation of Bi nanoparticles by novel cathodic dispersion of bulk bismuth electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xin [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Chen Shu; Huang Wei [Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Lushan Road, Changsha 410081 (China); Zheng Jufang [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Li Zelin, E-mail: lizelin@zjnu.c [Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Lushan Road, Changsha 410081 (China)

    2009-12-01

    A novel electrochemical approach has been developed to prepare clean bismuth nanoparticles (NPs) with a bulk Bi electrode in a 0.5 mol dm{sup -3} NaOH solution under highly cathodic polarization of -8 V versus a saturated mercurous sulfate electrode, requiring no any precursor ions and organic protective agents. The bulk Bi electrode can be facilely dispersed into Bi NPs at the condition of intensive hydrogen evolution. This cathodic dispersion of the bulk Bi electrode involves the formation and decomposition of unstable bismuth hydrides and the aggregation of atomic bismuth from the decomposition. Moreover, Bi{sub 2}O{sub 3} NPs have also been achieved by heating the precursor Bi NPs. Field-emission scanning electron microscopy, transmission electron microscope and X-ray diffraction were used to characterize these NPs. The as-prepared Bi NPs mainly existed in rhombohedral phase.

  2. Thin film bismuth iron oxides useful for piezoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  3. Bismuth pyrochlore-based thin films for dielectric energy storage

    Science.gov (United States)

    Michael, Elizabeth K.

    The drive towards the miniaturization of electronic devices has created a need for dielectric materials with large energy storage densities. These materials, which are used in capacitors, are a critical component in many electrical systems. Here, the development of dielectric energy storage materials for pulsed power applications, which require materials with the ability to accumulate a large amount of energy and then deliver it to the system rapidly, is explored. The amount of electrostatic energy that can be stored by a material is a function of the induced polarization and the dielectric breakdown strength of the material. An ideal energy storage dielectric would possess a high relative permittivity, high dielectric breakdown strength, and low loss tangent under high applied electric fields. The bismuth pyrochlores are a compositionally tunable family of materials that meet these requirements. Thin films of cubic pyrochlore bismuth zinc niobate, bismuth zinc tantalate, and bismuth zinc niobate tantalate, were fabricated using a novel solution chemistry based upon the Pechini method. This solution preparation is advantageous because it avoids the use of teratogenic solvents, such as 2-methoxyethanol. Crystalline films fabricated using this solution chemistry had very small grains that were approximately 27 nm in lateral size and 35 nm through the film thickness. Impedance measurements found that the resistivity of the grain boundaries was two orders of magnitude higher than the resistivity of the grain interior. The presence of many resistive grain boundaries impeded conduction through the films, resulting in high breakdown strengths for these materials. In addition to high breakdown strengths, this family of materials exhibited moderate relative permittivities of between 55 +/- 2 and 145 +/- 5, for bismuth zinc tantalate and bismuth zinc niobate, respectively, and low loss tangents on the order of 0.0008 +/- 0.0001. Increases in the concentration of the tantalum

  4. Separation of plutonium from lanthanum by electrolysis in LiCl KCl onto molten bismuth electrode

    Science.gov (United States)

    Serp, J.; Lefebvre, P.; Malmbeck, R.; Rebizant, J.; Vallet, P.; Glatz, J.-P.

    2005-04-01

    This work presents a study on the electroseparation of plutonium from lanthanum using molten bismuth electrodes in LiCl-KCl eutectic at 733 K. The reduction potentials of Pu3+ and La3+ ions were measured on a Bi thin film electrode using cyclic voltammetry (CV). A difference between the peak potentials for the formation of PuBi2 and LaBi2 of approximately 100 mV was found. Separation tests were then carried out using different current densities and salt phase compositions between a plutonium rod anode and an unstirred molten Bi cathode in order to evaluate the efficiency of an electrolytic separation process. At a current density of 12 mA/cm2/wt% (Pu3+), only Pu3+ ions are reduced into the molten Bi electrode, leaving La3+ ions in the salt melt. Similar results were found at two different Pu/La concentration ratios ([Pu]/[La] = 4 and 10). At a current density of 26 mA/cm2/wt% (Pu3+), co-reduction of Pu and La was observed as expected by the large negative potential of the Bi cathode during the separation test.

  5. Ferroelectric thin film bismuth titanate prepared from acetate precursors

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanxia; Hoelzer, D.T.; Schulze, W.A. [Alfred Univ., NY (United States); Tuttle, B.A.; Potter, B.G. [Sandia National Labs., Albuquerque, NM (United States)

    1994-10-01

    Bismuth titanate (Bi{sub 4}Ti{sub 3}O{sub 12}) thin films were fabricated by spin coat deposition followed by rapid thermal processing (RTP). Acetate derived solutions for deposition were synthesized by blending bismuth acetate in aqueous acetic acid and then adding titanium acetate. A series of electrically insulating, semiconducting and conducting substrates were evaluated for Bi{sub 4}Ti{sub 3}O{sub 12} film deposition. While X-ray diffraction and TEM analyses indicated that the initial perovskite crystallization temperature was 500{degrees}C or less for these Bi{sub 4}Ti{sub 3}O{sub 12} films, a 700{degrees}C crystallization treatment was used to obtain single phase perovskite films. Bi{sub 4}Ti{sub 3}O{sub 12} film crystallographic orientation was shown to depend on three factors: substrate surface morphology, the number of coating layers and thermal processing. While preferred c-direction orientation was observed for Bi{sub 4}Ti{sub 3}O{sub 12} films deposited on silver foil substrates, preferred a-direction orientation was obtained for films deposited on both Si and Pt coated Si wafers. The films were dense, smooth, crack free, and had grain sizes ranging from 20 nm to 100 nm. Film thickness and refractive index were determined using a combination of ellipsometry, waveguide refractometry and TEM measurements. Both low field dielectric and ferroelectric properties were measured for an 800 nm thick film deposited on a Pt coated MgO substrate. A remanent polarization of 38 {mu}C/cm{sup 2} and a coercive field of 98 kV/cm were measured for this film that was crystallized at 700{degrees}C.

  6. Electrodes modified with bismuth, antimony and tin precursor compounds for electrochemical stripping analysis of trace metals (a short review)

    OpenAIRE

    Lezi, Nikolitsa; Economou, Anastasios; Barek, Jiří

    2014-01-01

    Over the last decade, intensive research is being carried out towards the development of “green” electrochemical sensors. Bismuth, antimony and tin electrodes have been proposed as potential substitutes of mercury electrodes in electrochemical stripping analysis of trace metals. The main advantage of these metals as electrode materials is their lower toxicity compared to mercury. Among the different configuration of bismuth, antimony and tin electrodes, one of the most attractive inv...

  7. 有机-无机杂化复合铋膜电极溶出伏安法测痕量镉、铅离子%Fabrication of an organic-inorganic hybrid composite bismuth film electrode for stripping analysis of trace Cd( Ⅱ )and Pb( Ⅱ )

    Institute of Scientific and Technical Information of China (English)

    凌玉; 尹丽君; 刘刚; 李萍; 吴守国

    2011-01-01

    将铋和聚苯胺共沉积在玻碳电极上制备了杂化膜,然后在杂化膜上沉积一层铋膜,制备了一种新颖的电化学传感器——有机-无机杂化复合铋膜电极(HCBiFE),用于痕量重金属离子Cd(Ⅱ)和Pb(Ⅱ)的检测(0.1mol/L醋酸缓冲溶液,pH 4.7).优化了镀膜条件、离子测试参数.在1~90 μg·L-1的浓度范围内,两离子溶出峰电流与浓度呈现出良好的线性关系,富集时间120 s时,Cd(Ⅱ)和Pb(Ⅱ)的检测限分别低至0.2,0.5μg·L-1.该复合膜具有很好的稳定性和重现性,能够抗机械剥蚀、不易脱落,对50 μg·L-1的Cd(Ⅱ)和Pb(Ⅱ)连续测定50次,相对标准偏差分别为4.3%,6.1%.30 d后,该复合膜电极对Cd(Ⅱ)和Pb(Ⅱ)溶出峰电流分别下降3.2%,4.9%,表明该复合膜电极性能稳定,有望应用于环境水体的现场监测.%A novel electrochemical sensor(organic-inorganic hybrid composite bismuth film electrode)was fabricated on a glassy carbon substrate electrode by an electrochemical co-deposition of polyaniline and bismuth followed by plating a thin layer of bismuth on the hybrid film.The hybrid composite bismuth film electrode was applied to detect trace Cd(Ⅱ)and Pb( Ⅱ )in 0.1 mol/L acetate buffer solution(pH 4.7 )by square ware anodic stripping voltammetry.The influencing factors of stripping signals and the operational parameters were investigated in detail.The newly developed electrode revealed highly linear behavior in the examined concentration range from 1 to 90μg · L-1 for both test metal ions,with the detection limits of 0.2 μg · L-1 and 0.5 μg · L-1 for Cd( Ⅱ )and Pb( Ⅱ )respectively,offering good coefficients of variation(CVs)of 4.3% and 6.1% for Cd( Ⅱ )and Pb( Ⅱ )(50 μg · L-1,n=50)respectively.After 30 d,the stripping peak currents for 50 μg · L-1 Pb( Ⅱ )and Cd(Ⅱ)on the composite film were detected decreasing 3.2% and 4.9%,respectively.The long term stability makes it possible to be applied in on

  8. Investigation of solution-processed bismuth-niobium-oxide films

    International Nuclear Information System (INIS)

    The characteristics of bismuth-niobium-oxide (BNO) films prepared using a solution process were investigated. The BNO film annealed at 550 °C involving three phases: an amorphous phase, Bi3NbO7 fluorite microcrystals, and Nb-rich cubic pyrochlore microcrystals. The cubic pyrochlore structure, which was the main phase in this film, has not previously been reported in BNO films. The relative dielectric constant of the BNO film was approximately 140, which is much higher than that of a corresponding film prepared using a conventional vacuum sputtering process. Notably, the cubic pyrochlore microcrystals disappeared with increasing annealing temperature and were replaced with triclinic β-BiNbO4 crystals at 590 °C. The relative dielectric constant also decreased with increasing annealing temperature. Therefore, the high relative dielectric constant of the BNO film annealed at 550 °C is thought to result from the BNO cubic pyrochlore structure. In addition, the BNO films annealed at 500 °C contained approximately 6.5 atm. % carbon, which was lost at approximately 550 °C. This result suggests that the carbon in the BNO film played an important role in the formation of the cubic pyrochlore structure.

  9. Ultra-flat bismuth films for diamagnetic levitation by template-stripping

    Energy Technology Data Exchange (ETDEWEB)

    Kokorian, J. [University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); TU Delft — 3mE-PME, Mekelweg 2, 2628 CD Delft (Netherlands); Engelen, J.B.C. [University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); IBM Research — Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Vries, J. de; Nazeer, H.; Woldering, L.A. [University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Abelmann, L., E-mail: l.abelmann@utwente.nl [University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2014-01-01

    In this paper we present a method to deposit thin films of bismuth with sub-nanometer surface roughness for application to diamagnetic levitation. Evaporated films of bismuth have a high surface roughness with peak to peak values in excess of 100 nm and average values on the order of 20 nm. We expose the smooth backside of the films using a template stripping method, resulting in a great reduction of the average surface roughness, to 0.8 nm. Atomic force microscope and X-ray diffraction measurements show that the films have a polycrystalline texture with preferential c-axis orientation. On the back side of the film, fine grains are grouped into larger clusters. Cantilever resonance shift measurements indicate that the Young's modulus of the films is on the order of 20 GPa. - Highlights: • We deposited continuous but rough bismuth films of 200–500 nm in thickness by thermal evaporation. • We analyzed the material properties of bismuth films using a variety of measurement techniques. • We reduced the roughness of bismuth films from 20 nm to 0.8 nm by a template stripping method. • The Young's modulus of bismuth thin films is comparable to bulk bismuth.

  10. Part I: A comparative study of bismuth-modified screen-printed electrodes for lead detection

    Energy Technology Data Exchange (ETDEWEB)

    Calvo Quintana, Josefina [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy); Consorzio Interuniversitario Biostrutture e Biosistemi ' INBB' , Viale Medaglie d' Oro 305, 00136 Rome (Italy); Arduini, Fabiana, E-mail: fabiana.arduini@uniroma2.it [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy); Consorzio Interuniversitario Biostrutture e Biosistemi ' INBB' , Viale Medaglie d' Oro 305, 00136 Rome (Italy); Amine, Aziz [Faculte des Sciences et Techniques, B.P.146, Mohammadia, Morocco, Rome (Italy); Punzo, Francesco; Destri, Giovanni Li [LAMSUN and CSGI at Dipartimento di Scienze Chimiche, Universita degli Studi di Catania, Viale A. Doria 6, 95125, Catania (Italy); Bianchini, Chiara [Dipartimento di Ingegneria Chimica Materiali Ambienti dell' Universita degli Studi ' La Sapienza' di Roma, via Eudossiana 18, 00184 Rome (Italy); Zane, Daniela; Curulli, Antonella [Istituto per lo Studio dei Materiali Nanostrutturati (ISMN)-CNR,via del Castro Laurenziano 7, 00161 Rome (Italy); Palleschi, Giuseppe; Moscone, Danila [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy); Consorzio Interuniversitario Biostrutture e Biosistemi ' INBB' , Viale Medaglie d' Oro 305, 00136 Rome (Italy)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer 'In situ' Bi-SPE has higher sensitivity than 'ex situ' Bi-SPE and 'Bi{sub 2}O{sub 3} bulk' SPE. Black-Right-Pointing-Pointer Electrochemical treatment of SPE before Bi film deposition allows one to reach low LOD. Black-Right-Pointing-Pointer The linearity of Pb{sup 2+} in HCl and HClO{sub 4} is greatly affected by the ionic strength. Black-Right-Pointing-Pointer Satisfactory values of the recovery percentage were obtained in drinking water samples. - Abstract: Lead determination was carried out in the frame of the European Union project Biocop ( (www.biocop.org)) using a bismuth-modified screen-printed electrode (Bi-SPE) and the stripping analysis technique. In order to choose a sensitive Bi-SPE for lead detection, an analytical comparative study of electrodes modified by Bi using 'in situ', 'ex situ' and 'bulk' procedures was carried out. On the basis of the results obtained, we confirmed that the 'in situ' procedure resulted in better analytical performances with respect to not only 'ex situ' but also to 'Bi{sub 2}O{sub 3} bulk' modified electrodes, allowing for a linear range of lead ion concentration from 0.5 to 100 {mu}g L{sup -1} and a detection limit of 0.15 {mu}g L{sup -1}. We demonstrated that, before the Bi film deposition, an oxidative electrochemical pre-treatment of the working electrode could be useful because it eliminates traces of lead in the graphite-ink, as shown with stripping measurements. It also improves the electrochemical performance of the electrodes as demonstrated with Electrochemical Impedance Spectroscopy (EIS) measurements. The influence of different analytical parameters, such as the electrolyte solution composition (acetate buffer, chloridric acid, nitric acid, perchloric acid) and the ionic strength was investigated in order to evaluate how to treat the sample before the analysis. The morphology of

  11. Structural and optical characterization of thermally evaporated bismuth and antimony films for photovoltaic applications

    Science.gov (United States)

    Srimathy, N.; Ruban Kumar, A.

    2016-05-01

    In this present study, the thin film of bismuth and antimony is coated by thermal evaporation system equipped with the inbuilt ultra high vacuum system. XRD analysis confirmed the rhombohedral structure of Bismuth and Antimony on the prepared film. The surface roughness and physical appearance is analyzed by Atomic force microscopy. The results of Raman Spectroscopy show the wave functions and the spectrum of electrons. The preparation technique and conditions strongly influence the crystalline structure and the phase composition of bismuth and antimony thin films. The electrical and optical properties for the prepared film are analyzed. The results show a great interest and promising applications in Photovoltaic devices.

  12. Graphite felt modified with bismuth nanoparticles as negative electrode in a vanadium redox flow battery.

    Science.gov (United States)

    Suárez, David J; González, Zoraida; Blanco, Clara; Granda, Marcos; Menéndez, Rosa; Santamaría, Ricardo

    2014-03-01

    A graphite felt decorated with bismuth nanoparticles was studied as negative electrode in a vanadium redox flow battery (VRFB). The results confirm the excellent electrochemical performance of the bismuth modified electrode in terms of the reversibility of the V(3+) /V(2+) redox reactions and its long-term cycling performance. Moreover a mechanism that explains the role that Bi nanoparticles play in the redox reactions in this negative half-cell is proposed. Bi nanoparticles favor the formation of BiHx , an intermediate that reduces V(3+) to V(2+) and, therefore, inhibits the competitive irreversible reaction of hydrogen formation (responsible for the commonly observed loss of Coulombic efficiency of VRFBs). Thus, the total charge consumed during the cathodic sweep in this electrode is used to reduce V(3+) to V(2+) , resulting in a highly reversible and efficient process.

  13. Carbon nanotubes paste sensor modified with bismuth film for determination of metallic ions in ethanol fuel

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Gorla

    2015-05-01

    Full Text Available In the present study an anodic stripping voltammetric method using a bismuth film modified carbon nanotubes paste electrode for simultaneous determination of metals Zn2+, Cd2+and Pb2+in ethanol fuel is described. The metallic ions were preconcentrated on the bismuth film in the time and deposition potential of 500 s and -1.2 V and the stripping step was carried out by square wave voltammetry (frequency of 15 Hz, pulse amplitude of 25 mV and potential step of 5 mV. Acetate buffer at 0.1 mol L-1concentration and pH 4.5 was used as support electrolyte. The method showed linearity including the analytical blank up to 48.39 ?g L-1 for the metals and the obtained limits of detection were 3.36, 0.32 and 0.47 ?g L-1for Zn2+, Cd2+and Pb2+, respectively. The proposed method was applied in ethanol fuel samples.

  14. Anodic stripping voltammetric determination of traces of Pb(II) and Cd(II) using a glassy carbon electrode modified with bismuth nanoparticles

    International Nuclear Information System (INIS)

    We report on a glassy carbon electrode modified with bismuth nanoparticles (NanoBiE) for the simultaneous determination Pb2+ and Cd2+ by anodic stripping voltammetry. Operational parameters such as bismuth nanoparticles labelling amount, deposition potential, deposition time and stripping parameters were optimized with respect to the determination of Pb2+ and Cd2+ in 0.1 M acetate buffer solution (pH 4.5). The NanoBiE gives well-defined, reproducible and sharp stripping peaks. The peak current response increases linearly with the metal concentration in a range of 5.0–60.0 μg L−1, with a detection limit of 0.8 and 0.4 μg L−1 for Pb2+ and Cd2+, respectively. The morphology and composition of the modified electrode before and after voltammetric measurements were analysed by scanning electron microscopy and energy dispersive X-ray analysis. The NanoBiE was successfully applied to analysis of Pb2+ and Cd2+ in real water samples and the method was validated by ICP-MS technique, suggesting that the electrode can be considered as an interesting alternative to the bismuth film electrode for possible use in electrochemical studies and electro analysis. (author)

  15. A model bismuth oxide intergranular thin film in a ZnO twist grain boundary

    Energy Technology Data Exchange (ETDEWEB)

    Domingos, H S [INESC, Microsistemas and Nanotecnologias, Rua Alves Redol 1-9, P-1000-029 Lisbon (Portugal)

    2010-04-14

    The electronic properties of a model bismuth oxide intergranular film in ZnO were investigated using density functional plane wave calculations. It was found that oxygen excess plays a fundamental role in the appearance of electrical activity. The introduction by oxygen interstitials or zinc vacancies results in depletion of the charge in deep gap states introduced by the bismuth impurities. This makes the boundary less metallic and promotes the formation of acceptor states localized to the boundary core, resulting in Schottky barrier enhancement. The results indicate that the origin of electrical activity in thin intergranular bismuth oxide films is probably not distinct from that in decorated ZnO boundaries.

  16. Determination of (111) ordered domains on platinum electrodes by irreversible adsorption of bismuth.

    Science.gov (United States)

    Rodríguez, Paramaconi; Solla-Gullón, José; Vidal-Iglesias, Francisco J; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2005-08-15

    Irreversible adsorbed bismuth can be used to determine the fraction of (111) domains on a given platinum sample. On Pt(111) electrodes, the surface redox process of adsorbed bismuth takes place at 0.63 V in a well-defined peak. The behavior of this redox process on the Pt(111) vicinal surfaces indicates that the bismuth atoms involved in the redox process are only those deposited on the (111) terrace sites and that the charge under the peak at 0.63 V is directly proportional to the number of sites on (111) ordered domains (terraces). The good linear relationship obtained between the charge for the bismuth redox process and the number of (111) terrace sites on the vicinal surfaces allows construction of a calibration curve. This calibration curve has been used to directly estimate the amount of (111) ordered domain terrace sites on polycrystalline platinum samples with different surface ordered domains. The results agree with what we would expect from our knowledge of these surfaces. PMID:16097774

  17. Underpotential Deposition Study and Determination of Bismuth on Gold Electrode by Using Voltammetry

    Institute of Scientific and Technical Information of China (English)

    DU,Yong-Ling(杜永令); WANG,Chun-Ming(王春明)

    2002-01-01

    The cyclic voltammetry (CV) and the semidifferential anodic stripping voltanmetry (SdASV) were used for investigation of bismuth(Ⅲ) underpotential deposition (UPD) on gold electrode. Based on the excellent electrochemical properties of Au/Bi UPD system, a new method for determining bismuth (Ⅲ)was established. A solution of 0.1 mol/L HNO3 was selected as the supporting electrolyte. Factors affecting the Bi(Ⅲ) UPD and stripping steps were investigated and an opthmized analytical procedure was developed. The calibration plots for Bi(Ⅲ) concentration in the range 1.25 × 10-8-1.0 × 10-7 mol/L were obtained. The detection limit, calculated as three times the standard deviation of the analytical signal of 8.3×10-8 mol/L for a 90 s electrodeposition at 0.00 V (while the solution magnetically stirred at a speed of 300 rpm), was 7.5× 10-9 mol/ L. For8 successive determinations of 1.25 × 10-7 mol/L Bi(Ⅲ), the obtained RSD (relative standard deviation) was 0.4%. The developed method was applied to bismuth determining in medicine and urine samples. The analytical results were compared with that of atomic emission spectrometry (AES) method.

  18. Microwave and magneto-optic properties of bismuth-substituted yttrium iron garnet thin films

    Science.gov (United States)

    Butler, J. C.; Kramer, J. J.; Esman, R. D.; Craig, A. E.; Lee, J. N.; Ryuo, T.

    1990-05-01

    Microwave and magneto-optic measurements have been made on bismuth-substituted yttrium iron garnet (BiYIG) films. Forward-volume (FV) magnetostatic-wave (MSW) attenuation has been measured from ferrimagnetic resonance and from pulse delay data. We report the indirect observation of FV MSW in BiYIG using two independent techniques: a pulse transmission technique and a passband measurement technique. Faraday rotation in the films was also recorded at a wavelength of 1.3 μm. The bismuth-substituted films are grown on carefully cleaned substrates and have yttrium:bismuth ratios of 1:1. The composition of the bismuth substituted films is Y1.5Bi1.5Fe5O12 deduced from lattice parameters and absolute Faraday rotation. These films show particular promise for use in waveguide-type high-speed MSW-optical devices where low MSW attenuation and high Faraday rotation are among the necessary criteria for successful operation.

  19. Group III-nitride thin films grown using MBE and bismuth

    Science.gov (United States)

    Kisielowski, Christian K.; Rubin, Michael

    2000-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  20. Opto-electronic properties of bismuth oxide films presenting different crystallographic phases

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Celia L. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Depablos-Rivera, Osmary, E-mail: osmarydep@yahoo.com [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Posgrado en Ciencia e Ingeniería de Materiales, UNAM, Unidad de Posgrado, Edificio C, Piso 1, Zona Cultural de CU, México, D.F. 04510 (Mexico); Silva-Bermudez, Phaedra [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Instituto Nacional de Rehabilitación, Calz. México Xochimilco No. 289 Col. Arenal de Guadalupe, C.P.14389, Ciudad de México, D.F. (Mexico); Muhl, Stephen [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico); Zeinert, Andreas; Lejeune, Michael; Charvet, Stephane; Barroy, Pierre [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex 1 (France); Camps, Enrique [Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, kilómetro 36.5. La Marquesa, Municipio de Ocoyoacac, CP 52750, Estado de México (Mexico); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n CU, México D.F. 04510 (Mexico)

    2015-03-02

    The optical, electrical and structural properties of bismuth oxide thin films deposited by radio frequency reactive magnetron sputtering were studied. The Bi{sub 2}O{sub 3} thin films were grown on Si and glass substrates under different power and substrate temperatures in an oxygen-enriched plasma leading to films with different crystalline phase as evidenced by X-ray diffraction and Raman spectroscopy. The optical properties of the films were measured using ellipsometric spectroscopy and optical transmission spectra. In order to parameterize the optical dispersion functions (n, k) of the films, the Tauc–Lorentz dispersion model was used. The optical bandgap was then assessed by different methods and the results are compared to the thermal variations of the electrical resistivity of the films. It was found that the refractive index, extinction coefficient and optical gap strongly depend on the deposition conditions and the crystalline phase; the fluorite defect cubic δ-Bi{sub 2}O{sub 3} phase showed the lowest optical gap and lower resistivity. - Highlights: • Different bismuth oxide phases were obtained by sputtering. • The power and substrate temperature were the two key parameters. • Room temperature delta-Bi{sub 2}O{sub 3} thin films were obtained. • The optical bandgap was around 1.5 and 2.2 eV, depending on the phase. • The bismuth oxide films presented activation energies around 1 eV.

  1. Phase transition of bismuth telluride thin films grown by MBE

    DEFF Research Database (Denmark)

    Fülöp, Attila; Song, Yuxin; Charpentier, Sophie;

    2014-01-01

    A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formatio...

  2. Ultrafast electron diffraction studies of optically excited thin bismuth films

    Energy Technology Data Exchange (ETDEWEB)

    Rajkovic, Ivan

    2008-10-21

    This thesis contains work on the design and the realization of an experimental setup capable of providing sub-picosecond electron pulses for ultrafast electron diffraction experiments, and performing the study of ultrafast dynamics in bismuth after optical excitation using this setup. (orig.)

  3. Highly selective amperometric sensor for the trace level detection of hydrazine at bismuth nanoparticles decorated graphene nanosheets modified electrode.

    Science.gov (United States)

    Devasenathipathy, Rajkumar; Mani, Veerappan; Chen, Shen-Ming

    2014-06-01

    A highly selective amperometric sensor was developed for the trace level determination of hydrazine at bismuth nanoparticles (Bi) decorated graphene nanosheets (GR) composite film modified glassy carbon electrode (GCE). GR-Bi nanocomposite has been successfully prepared via simple and facile chemical reduction approach and its structure was characterized by various techniques. Surface morphological and X-ray diffraction studies revealed the formation and high loading of Bi nanoparticles on graphene sheets. GR-Bi nanocomposite modified GCE exhibited greatly enhanced electrocatalytic performance towards electro-oxidation of hydrazine in terms of decrease in overpotential and increase in oxidation peak current (Ip). The kinetic parameters such as electron transfer coefficient (α) and diffusion coefficient (Do) of the hydrazine oxidation were determined to be 0.70 and 2.65×10(-5) cm(2) s(-1), respectively. An amperometric sensor has been fabricated which detects trace level concentration of hydrazine. The sensor exhibited a wide linear range from 20 nM to 0.28 mM and a very low detection limit (LOD) of 5 nM. Remarkably, this is the lowest LOD achieved for the determination of hydrazine in neutral pH among other reported electrochemical hydrazine sensors. In addition, the sensor selectively detects hydrazine even in the presence of 1000 fold excess quantity of common interferrants. The practical feasibility of the sensor has been assessed in water and urine samples with good recoveries. Furthermore, the sensor exhibited appreciable stability, repeatability and reproducibility results.

  4. A novel tin-bismuth alloy electrode for anodic stripping voltammetric determination of zinc

    International Nuclear Information System (INIS)

    We report on a novel tin-bismuth alloy electrode (SnBiE) for the determination of trace concentrations of zinc ions by square-wave anodic stripping voltammetry without deoxygenation. The SnBiE has the advantages of easy fabrication and low cost, and does not require a pre-treatment (in terms of modification) prior to measurements. A study on the potential window of the electrode revealed a high hydrogen overvoltage though a limited anodic range due to the oxidation of tin. The effects of pH value, accumulation potential, and accumulation time were optimized with respect to the determination of trace zinc(II) at pH 5. 0. The response of the SnBiE to zinc(II) ion is linear in the 0.5-25 μM concentration range. The detection limit is 50 nM (after 60 s of accumulation). The SnBiE was applied to the determination of zinc(II) in wines and honeys, and the results were consistent with those of AAS. (author)

  5. Thermoelectric properties and micro-structure characteristics of annealed N-type bismuth telluride thin film

    International Nuclear Information System (INIS)

    N-type bismuth telluride (Bi2Te3) thermoelectric thin films were deposited by co-sputtering simple substance Te and Bi targets. The deposited films were annealed under various temperatures. The composition ratio, micro-structure and thermoelectric properties of the prepared films were systematically investigated by energy dispersive spectrometer, X-ray diffraction, four-probe method and Seebeck coefficient measurement system. When the annealing temperature is 400 °C, the stoichiometric N-type Bi2Te3 film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10−3 W m−1 K−2. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi2Te3 film annealed at film 400 °C on the applied temperature ranging from 25 °C to 315 °C was investigated. The results show that a highest power factor of 3.288 × 10−3 W m−1 K−2 is obtained at the applied temperature of 275 °C. The structural and thermoelectric properties of the deposited bismuth telluride thin films are greatly improved by annealing and the Seebeck coefficient, electrical conductivity and power factor increase with the applied temperature rising, which are helpful and could be guidance for preparing the high-performance thin film thermoelectric materials for thermoelectric application.

  6. Sol-gel synthesis and property studies of layered perovskite bismuth titanate thin films

    International Nuclear Information System (INIS)

    Layered perovskite bismuth titanate (BTO) thin films were deposited on platinum coated silicon substrates by spin coating. A homogeneous and stable precursor solution was prepared by sol-gel process using bismuth nitrate and titanium(IV) butoxide as starting materials, glacial acetic acid and ethanolamine were selected as solvent and stabilizing agent, respectively. The crystal structure, surface morphology, composition and electrical properties of the films have been investigated. Crystal structure and morphology of the films are strongly influenced by the heat cycle adopted to form crystalline BTO films. Morphology of the films studied by AFM is found to be smooth, dense, and crack free. The deposited films possess good compositional homogeneity and thickness uniformity. The dielectric constant and the dissipation factor measured at 1 kHz at room temperature are found to be 135 and 0.018, respectively, for the films of 0.4-μm thickness annealed at 600 deg. C for 1 h. The remnant polarization and coercive field values are estimated to be 5 μC cm-2 and 45 kV cm-1. The films possess good fatigue properties and useful for application in the non-volatile memories

  7. Sol-gel synthesis and property studies of layered perovskite bismuth titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Madeswaran, S.; Giridharan, N.V.; Jayavel, R

    2003-04-29

    Layered perovskite bismuth titanate (BTO) thin films were deposited on platinum coated silicon substrates by spin coating. A homogeneous and stable precursor solution was prepared by sol-gel process using bismuth nitrate and titanium(IV) butoxide as starting materials, glacial acetic acid and ethanolamine were selected as solvent and stabilizing agent, respectively. The crystal structure, surface morphology, composition and electrical properties of the films have been investigated. Crystal structure and morphology of the films are strongly influenced by the heat cycle adopted to form crystalline BTO films. Morphology of the films studied by AFM is found to be smooth, dense, and crack free. The deposited films possess good compositional homogeneity and thickness uniformity. The dielectric constant and the dissipation factor measured at 1 kHz at room temperature are found to be 135 and 0.018, respectively, for the films of 0.4-{mu}m thickness annealed at 600 deg. C for 1 h. The remnant polarization and coercive field values are estimated to be 5 {mu}C cm{sup -2} and 45 kV cm{sup -1}. The films possess good fatigue properties and useful for application in the non-volatile memories.

  8. Rapid Determination of Uranium in Water Samples by Adsorptive Cathodic Stripping Voltammetry Using a Tin-Bismuth Alloy Electrode

    International Nuclear Information System (INIS)

    In this work, the tin-bismuth alloy electrode (SnBiE) was used for U(VI) concentration determination for the first time. Compared to the conventional solid electrode (glassy carbon electrode and bismuth bulk electrode), the SnBiE possesses a higher hydrogen overpotential, which indicates that the tin-bismuth alloy can considerably extend the application of potentially available electrode detection systems. Combining with electrochemical behavior analysis and spectrometric measurements as well as theoretical calculation methods, the geometric structures of uranium-cupferron (N-nitrosophenylhydroxylamine) complexes have been revealed and a more detailed electrode mechanism has been proposed. The electroanalysis results show that the optimal sensitivity could be obtained by using diphenylguanidine as the auxiliary reagent. The calibration plot for U(VI) quantification was linear from 0.5 nM to 30 nM with a correlation coefficient of 0.999. In the meanwhile, a detection limit of 0.24 nM was obtained in connection with an accumulation time of 30 s, which is comparable with that of mercury analogues. The practical applications of SnBiE have been tentatively performed for the determination of UO22+ in real water samples and the results were well consistent with those by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). A very simple, convenient and cheap approach was established for the determination of UO22+ in natural water samples containing surfactants without the otherwise necessity of sample pretreatment, which drastically reduce the analysis time

  9. Amperometric Noise at Thin Film Band Electrodes

    DEFF Research Database (Denmark)

    Larsen, Simon T.; Heien, Michael L.; Taboryski, Rafael

    2012-01-01

    polymers and measured the current noise in physiological buffer solution for a wide range of different electrode areas. The noise measurements could be modeled by an analytical expression, representing the electrochemical cell as a resistor and capacitor in series. The studies revealed three domains......; for electrodes with low capacitance, the amplifier noise dominated, for electrodes with large capacitances, the noise from the resistance of the electrochemical cell was dominant, while in the intermediate region, the current noise scaled with electrode capacitance. The experimental results and the model......Background current noise is often a significant limitation when using constant-potential amperometry for biosensor application such as amperometric recordings of transmitter release from single cells through exocytosis. In this paper, we fabricated thin-film electrodes of gold and conductive...

  10. Facile production of thermoelectric bismuth telluride thick films in the presence of polyvinyl alcohol.

    Science.gov (United States)

    Lei, C; Burton, M R; Nandhakumar, I S

    2016-06-01

    Bismuth telluride is currently the best performing thermoelectric material for room temperature operations in commercial thermoelectric devices. We report the reproducible and facile production of 600 micron thick bismuth telluride (Bi2Te3) layers by low cost and room temperature pulsed and potentiostatic electrodeposition from a solution containing bismuth and tellurium dioxide in 2 M nitric acid onto nickel in the presence of polyvinyl alcohol (PVA). This was added to the electrolyte to promote thick layer formation and its effect on the structure, morphology and composition of the electrodeposits was investigated by SEM and EDX. Well adherent, uniform, compact and stoichiometric n-type Bi2Te3 films with a high Seebeck coefficient of up to -200 μV K(-1) and a high electrical conductivity of up to 400 S cm(-1) resulting in a power factor of 1.6 × 10(-3) W m(-1) K(-2) at film growth rates of 100 μm h(-1) for potentiostatic electrodeposition were obtained. The films also exhibited a well defined hexagonal structure as determined by XRD.

  11. Microscopic and electrochemical characterization of lead film electrode applied in adsorptive stripping analysis

    International Nuclear Information System (INIS)

    Lead film electrodes (PbFEs) deposited in situ on glassy carbon or carbon paste supports have recently found application in adsorptive stripping voltammetric determination of inorganic ions and organic substances. In this work, the PbFE, prepared in ammonia buffer solutions, was investigated using scanning electron microscopy, atomic force microscopy and various voltammetric techniques. The microscopic images of the lead films deposited on the glassy carbon substrate showed a considerable variability in microstructure and compactness of the deposited layer depending on the selected experimental conditions, such as the concentration of Pb(II) species, the nucleation and deposition potential, and the time applied. The catalytic adsorptive systems of cobalt and nickel in a solution containing 0.1 ammonia buffer, 2.5 x 10-5 M nioxime and 0.25 M NaNO2 were employed to investigate the electrochemical characteristics and utility of the in situ prepared lead films. The optimal parameters, i.e. the lead concentration in the solution, the procedure of film removal, and the time and potential of lead nucleation and film deposition for the adsorptive determination of metal traces, were selected, resulting in the very good reproducibility (RSD = 4.2% for 35 scans) of recorded signals. The voltammetric utility of the lead film electrode was compared to that of glassy carbon, mercury film and bismuth film electrodes, and was subsequently evaluated as superior.

  12. Synthesis of mercuric iodide and bismuth tri-iodide nanoparticles for heavy metal iodide films nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Fornaro, L.; Pereira, H.Bentos [Compound Semiconductors Group, CURE, Universidad de la Republica, Rocha (Uruguay); Aguiar, I.; Perez Barthaburu, M. [Compound Semiconductors Group, Facultad de Quimica, Univ. de la Republica, Montevideo (Uruguay)

    2011-12-15

    We synthesized mercuric iodide and bismuth tri-iodide nanoparticles by suspension in octadecene, from Hg(NO{sub 3}){sub 2}.H{sub 2}O and I{sub 2}, and from Bi(NO{sub 3}){sub 3}.5H{sub 2}O and I{sub 2}, respectively. The best synthesis conditions were 2 h at 70-80 C, followed by 10 min at 110 C for mercuric iodide nanoparticles, and 4 h at 80-110 C, followed by 10 min at 180-210 C for bismuth tri-iodide ones. Nanoparticles were then washed and centrifuged with ether repeatedly. Compounds identity was confirmed by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). We found shifts of the X-ray diffraction maxima for nanoparticles of both compounds. We characterized the nanoparticles by transmission (TEM) and scanning (SEM) electron microscopy. We obtained disk-like and squared mercuric iodide nanostructures, 80-140 nm and 100-125 nm in size respectively. We also obtained rounded and rod-like bismuth tri-iodide nanoparticles, 30-500 nm in size. Acetonitrile and isopropanol suspensions of mercuric iodide nanoparticles, and acetonitrile suspension of bismuth tri-iodide nanoparticles exhibited peak maxima shifts in their UV-Vis spectra. We synthesized for the first time mercuric iodide and bismuth tri-iodide nanoparticles by the suspension method, although we have not yet obtained uniform shape and size distributions. They offer interesting perspectives for crystalline film nucleation and for improving current applications of these materials, as well as for opening new ones. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Photovoltaic enhancement based on improvement of ferroelectric property and band gap in Ti-doped bismuth ferrite thin films

    International Nuclear Information System (INIS)

    Highlights: • The leakage current is effectively reduced by adding a certain amount of titanium. • Addition of titanium increases the remnant polarization and decreases the band gap. • The power conversion efficiency increases as titanium content increases. - Abstract: Ti-doped bismuth ferrite thin films were prepared via sol–gel spin-coating method. The effects of titanium on the microstructure, optical, leakage, ferroelectric and photovoltaic characteristics have been investigated systematically. The result shows that bismuth ferrite thin films doped with 0–8 at.% Ti are rhombohedral distortion perovskite structure. The addition of titanium inhibits the grain growth and enhances the thickness uniformity and can decrease the band gap of bismuth ferrite thin films. The leakage current of bismuth ferrite thin films is effectively reduced by adding a certain amount of titanium and the leakage mechanism has been investigated. Addition of titanium increases the remnant polarization of the films. As titanium content increases, the short circuit photocurrent density decrease first and then increase, while the open circuit photovoltage increase first and then decrease. The power conversion efficiency of Ti-doped bismuth ferrite thin films increases as titanium content increases, which can be explained as a result of the increased remnant polarization and decreased band gap

  14. Optical characterization of antimony-based bismuth-doped thin films with different annealing temperatures

    Institute of Scientific and Technical Information of China (English)

    Xinmiao Lu; Yiqun Wu; Yang Wang; Jinsong Wei

    2011-01-01

    Antimony-b ased bismuth-doped thin film,a new kind of super-resolution mask layer,is prepared by magnetron sputtering.The structures and optical constants of the thin films before and after annealing are examined in detail.The as-deposited film is mainly in an amorphous state.After annealing at 170-370℃,it is converted to the rhombohedral-type of structure.The extent of crystallization increased with the annealing temperature.When the thin film is annealed,its refractive index decreased in the most visible region,whereas the extinction coefficient and reflectivity are markedly increased.The results indicate that the optical parameters of the film strongly depend on its microstructure and the bonding of the atoms.As demand for ultrahigh-density information storage continues to grow the recording mark size in optical memory is reduced to the nanometer scale [1- 4].Exceeding the optical diffraction limit with traditional optical storage technology has become a challenge[5-6].%Antimony-based bismuth-doped thin film, a new kind of super-resolution mask layer, is prepared by magnetron sputtering. The structures and optical constants of the thin films before and after annealing are examined in detail. The as-deposited film is mainly in an amorphous state. After annealing at 170-370℃, it is converted to the rhombohedral-type of structure. The extent of crystallization increased with the annealing temperature. When the thin film is annealed, its refractive index decreased in the most visible region, whereas the extinction coefficient and reflectivity are markedly increased. The results indicate that the optical parameters of the film strongly depend on its microstructure and the bonding of the atoms.

  15. Optical and electrical properties of thin films of bismuth ferric oxide

    International Nuclear Information System (INIS)

    The bismuth ferric oxide (BFO) has caused great attention in recent years because of their multi ferric properties, making it very attractive for different technological applications. In this paper simultaneous ablation of two white (Bi and Fe2O3) was used in a reactive atmosphere (containing oxygen) to deposit thin films of BFO. The composition of the films is changed by controlling the plasma parameters such as the average kinetic energy of the ions (E p) and the plasma density (Np). The effects caused by excess of Bi and Fe in atomic structure and the optical and electrical properties of the films BiFeO3 in terms of plasma parameters were studied. The X-ray diffraction patterns of BFO samples with excess of bismuth above 2% at. They exhibited small changes in structure leading to improved levels of leakage currents compared to levels of the film with a stoichiometry close to BiFeO3 composition. These samples showed a secondary phase (Bi25FeO40 selenite type) that led to the increase in the values of band gap and resistivity as well as the improvement of the piezoelectric properties. On the other hand, the films with iron excess showed as secondary phase compounds of iron oxide (α - γ-Fe2O3) that caused increments in the conductivity and decrease in the values of band gap. The results are discussed in terms of the excesses of Bi and Fe which were correlated with the plasma parameters. (Author)

  16. Bismuth nanoparticle decorating graphite felt as a high-performance electrode for an all-vanadium redox flow battery.

    Science.gov (United States)

    Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

    2013-03-13

    Employing electrolytes containing Bi(3+), bismuth nanoparticles are synchronously electrodeposited onto the surface of a graphite felt electrode during operation of an all-vanadium redox flow battery (VRFB). The influence of the Bi nanoparticles on the electrochemical performance of the VRFB is thoroughly investigated. It is confirmed that Bi is only present at the negative electrode and facilitates the redox reaction between V(II) and V(III). However, the Bi nanoparticles significantly improve the electrochemical performance of VRFB cells by enhancing the kinetics of the sluggish V(II)/V(III) redox reaction, especially under high power operation. The energy efficiency is increased by 11% at high current density (150 mA·cm(-2)) owing to faster charge transfer as compared with one without Bi. The results suggest that using Bi nanoparticles in place of noble metals offers great promise as high-performance electrodes for VRFB application.

  17. Bismuth nanoparticle decorating graphite felt as a high-performance electrode for an all-vanadium redox flow battery.

    Science.gov (United States)

    Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

    2013-03-13

    Employing electrolytes containing Bi(3+), bismuth nanoparticles are synchronously electrodeposited onto the surface of a graphite felt electrode during operation of an all-vanadium redox flow battery (VRFB). The influence of the Bi nanoparticles on the electrochemical performance of the VRFB is thoroughly investigated. It is confirmed that Bi is only present at the negative electrode and facilitates the redox reaction between V(II) and V(III). However, the Bi nanoparticles significantly improve the electrochemical performance of VRFB cells by enhancing the kinetics of the sluggish V(II)/V(III) redox reaction, especially under high power operation. The energy efficiency is increased by 11% at high current density (150 mA·cm(-2)) owing to faster charge transfer as compared with one without Bi. The results suggest that using Bi nanoparticles in place of noble metals offers great promise as high-performance electrodes for VRFB application. PMID:23398147

  18. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Surbhi [Department of Physics and Astrophysics, University of Delhi (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi (India)

    2015-03-15

    The influence of Cerium doping on the structural and magnetic properties of BiFeO{sub 3} thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi{sub 1−x}Ce{sub x}FeO{sub 3} (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm{sup −1}) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm{sup −1}), shows a minor shift. Sudden evolution of Raman mode at 668 cm{sup −1}, manifested as A{sub 1}-tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (M{sub s}) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi{sub 0.88}Ce{sub 0.12}FeO{sub 3} thin film found to exhibit better magnetic properties with M{sub s}=15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi{sub 1−x}Ce{sub x}FeO{sub 3} thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical

  19. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    International Nuclear Information System (INIS)

    The influence of Cerium doping on the structural and magnetic properties of BiFeO3 thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi1−xCexFeO3 (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm−1) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm−1), shows a minor shift. Sudden evolution of Raman mode at 668 cm−1, manifested as A1-tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (Ms) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi0.88Ce0.12FeO3 thin film found to exhibit better magnetic properties with Ms=15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi1−xCexFeO3 thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical applications of such materials exhibiting pinching behavior are conferred

  20. Magnetoelectric thin film composites with interdigital electrodes

    Science.gov (United States)

    Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knöchel, R.; Quandt, E.

    2013-07-01

    Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

  1. Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Airul Azha Abd [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Technology Park Malaysia, Malaysia Institute of Microelectronics and System, Kuala Lumpur (Malaysia); Umar, Akrajas Ali; Salleh, Muhamad Mat [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Chen, Xiaomei [Jimei University, College of Food and Biological Engineering, Jimei, Xiamen (China); Oyama, Munetaka [Kyoto University, Graduate School of Engineering, Nishikyoku, Kyoto (Japan)

    2016-02-15

    The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m{sup -1} K{sup -2}) and 10 μV/K (and 19.5 μW m{sup -1} K{sup -2}), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output

  2. Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

    International Nuclear Information System (INIS)

    The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m-1 K-2) and 10 μV/K (and 19.5 μW m-1 K-2), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output load as high as 50

  3. Mechanical properties of bismuth implanted amorphous Ge film

    Energy Technology Data Exchange (ETDEWEB)

    Juhasz, A.; Szommer, P.; Lendvai, J.; Vertesy, Z.; Peto, G. E-mail: peto@mfa.kfki.hu

    1999-01-02

    Mechanical properties of Bi ion implanted a-Ge film were studied by dynamic microhardness tests and compared to those of unimplanted a-Ge film. 400 nm thick films were evaporated in units of 30 nm thick layers and bombarded with Bi ions at 60 keV energy and 2 {mu}A/cm{sup 2} current. Cyclic load-unload indentation tests and indentation creep tests were performed to determine the hardness and ductility of the ion implanted and unimplanted specimens, respectively. The brittleness of the materials was characterised by scanning electron microscopic observation of crack formation around the Vickers indentations. The dynamic hardness was much larger, the ductility lower, the crack formation was significantly larger in the case of the unimplanted than in the ion bombarded specimens. The observed differences in the mechanical properties indicate structural differences between the two types of a-Ge are in agreement with the earlier reported formation of a new amorphous phase of Ge induced by ion implantation (G. Peto, J. Kanski, U. Sodervall, Phys. Lett. 124 (1987) 510)

  4. Mechanical properties of bismuth implanted amorphous Ge film

    Science.gov (United States)

    Juhász, A.; Szommer, P.; Lendvai, J.; Vértesy, Z.; Pető, G.

    1999-01-01

    Mechanical properties of Bi ion implanted a-Ge film were studied by dynamic microhardness tests and compared to those of unimplanted a-Ge film. 400 nm thick films were evaporated in units of 30 nm thick layers and bombarded with Bi ions at 60 keV energy and 2 μA/cm 2 current. Cyclic load-unload indentation tests and indentation creep tests were performed to determine the hardness and ductility of the ion implanted and unimplanted specimens, respectively. The brittleness of the materials was characterised by scanning electron microscopic observation of crack formation around the Vickers indentations. The dynamic hardness was much larger, the ductility lower, the crack formation was significantly larger in the case of the unimplanted than in the ion bombarded specimens. The observed differences in the mechanical properties indicate structural differences between the two types of a-Ge are in agreement with the earlier reported formation of a new amorphous phase of Ge induced by ion implantation (G. Pető, J. Kanski, U. Sodervall, Phys. Lett. 124 (1987) 510 [6]).

  5. Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron garnet thin films

    Energy Technology Data Exchange (ETDEWEB)

    Deb, Marwan, E-mail: marwan.deb@ipcms.unistra.fr; Vomir, Mircea; Rehspringer, Jean-Luc; Bigot, Jean-Yves [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, CNRS, Université de Strasbourg, BP 43, 23 rue du Loess, 67034 Strasbourg Cedex 02 (France)

    2015-12-21

    Controlling the magnetization dynamics on the femtosecond timescale is of fundamental importance for integrated opto-spintronic devices. For industrial perspectives, it requires to develop simple growth techniques for obtaining large area magneto-optical materials having a high amplitude ultrafast Faraday or Kerr response. Here we report on optical pump probe studies of light induced spin dynamics in high quality bismuth doped iron garnet polycrystalline film prepared by the spin coating method. We demonstrate an ultrafast non-thermal optical control of the spin dynamics using both circularly and linearly polarized pulses.

  6. Preparation and characterization of nanostructured copper bismuth diselenide thin films from a chemical route

    Indian Academy of Sciences (India)

    R H Bari; L A Patil

    2010-12-01

    Thin films of copper bismuth diselenide were prepared by chemical bath deposition technique onto glass substrate below 60°C. The deposition parameters such as time, temperature of deposition and pH of the solution, were optimized. The set of films having different elemental compositions was prepared by varying Cu/Bi ratio from 0.13–1.74. Studies on structure, composition, morphology, optical absorption and electrical conductivity of the films were carried out and discussed. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX), absorption spectroscopy, and electrical conductivity. The results are discussed and interpreted.

  7. Bismuth Nanoparticle Decorating Graphite Felt as a High-Performance Electrode for an All-Vanadium Redox Flow Battery

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chong M.; Sprenkle, Vincent L.; Wang, Wei

    2013-02-04

    The selection of electrode materials plays a great role in improving performances of all vanadium redox flow batteries (VRBs). Low-cost graphite felt (GF) as traditional electrode material has to be modified to address its issue of low electrocatalytic activity. In our paper, low-cost and highly conductive bismuth nanoparticles, as a powerful alternative electrocatalyst to noble metal, are proposed and synchronously electro-deposited onto the surface of GF while running flow cells employing the electrolytes containing suitable Bi3+. Although bismuth is proved to only take effect on the redox reaction of V(II)/V(III) and present at negative half-cell side, the whole cell electrochemical performances are significantly improved. In particular, the energy efficiency is increased by 11% owing to faster charge transfer as compared with one without Bi at high charge/discharge rate of 150 mA/cm2, which is prone to reduce stack size, thus dramatically reducing the cost. The excellent results show great promise of Bi nano-catalysts in the commercialization of VRBs in terms of product cost as well as electrochemical properties.

  8. Method for synthesizing thin film electrodes

    Science.gov (United States)

    Boyle, Timothy J.

    2007-03-13

    A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

  9. Bismuth Substituted Yttrium Iron Garnet Single Crystal Films Prepared by Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Magneto-optic Faraday rotation effect and the amount of bismuth substituted in yttrium iron garnet single crystal films prepared by gel-coating on modified gadolinium-gallium garnet substrates are investigated, where the gel is synthesized by a sol-gel reaction of nitrates and ethylene glycol. The coated gel is annealed in air at temperatures up to 660℃ for 4h, which is about 300℃ lower than that of liquid-phase epitaxy. The maximum amount of Bi substitution is x=2.7 and the crystallization temperature of garnet phase decreases with the increase of x down to 520℃ for x=2.7. In this film, a huge Faraday rotation of -8.1×104 (°)/cm at λ=0.633μm is obtained.

  10. Bismuth ferrite based thin films, nanofibers, and field effect transistor devices

    Science.gov (United States)

    Rivera-Beltran, Rut

    In this research an attempt has been made to explore bismuth ferrite thin films with low leakage current and nanofibers with high photoconductivity. Thin films were deposited with pulsed laser deposition (PLD) method. An attempt has been made to develop thin films under different deposition parameters with following target compositions: i) 0.6BiFeO3-0.4(Bi0.5 K0.5)TiO3 (BFO-BKT) and ii) bi-layered 0.88Bi 0.5Na0.5TiO3-0.08Bi0.5K0.5TiO 3-0.04BaTiO3/BiFeO3 (BNT-BKT-BT/BFO). BFO-BKT thin film shows suppressed leakage current by about four orders of magnitude which in turn improve the ferroelectric and dielectric properties of the films. The optimum remnant polarization is 19 muC.cm-2 at the oxygen partial pressure of 300 mtorr. The BNT-BKT-BT/BFO bi-layered thin films exhibited ferroelectric behavior as: Pr = 22.0 muC.cm-2, Ec = 100 kV.cm-1 and epsilonr = 140. The leakage current of bi-layered thin films have been reduced two orders of magnitude compare to un-doped bismuth ferrite. Bismuth ferrite nanofibers were developed by electrospinning technique and its electronic properties such as photoconductivity and field effect transistor performance were investigated extensively. Nanofibers were deposited by electrospinning of sol-gel solution on SiO2/Si substrate at driving voltage of 10 kV followed by heat treatment at 550 °C for 2 hours. The composition analysis through energy dispersive detector and electron energy loss spectroscopy revealed the heterogeneous nature of the composition with Bi rich and Fe deficient regions. X-ray photoelectron spectroscopy results confirmed the combination of Fe3+ and Fe2+ valence state in the fibers. The photoresponse result is almost hundred times higher for a fiber of 40 nm diameter compared to a fiber with 100 nm diameter. This effect is described by a size dependent surface recombination mechanism. A single and multiple BFO nanofibers field effect transistors devices were fabricated and characterized. Bismuth ferrite FET behaves

  11. Growth of epitaxial sodium-bismuth-titanate films by metal-organic chemical vapor phase deposition

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzkopf, J., E-mail: schwarzkopf@ikz-berlin.de [Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin (Germany); Schmidbauer, M.; Duk, A.; Kwasniewski, A. [Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin (Germany); Anooz, S. Bin [Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin (Germany); Physics Department, Faculty of Science, Hadhramout University of Science and Technology, Mukalla 50511, Republic of Yemen (Yemen); Wagner, G. [Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin (Germany); Devi, A. [Inorganic Materials Chemistry, Ruhr-University Bochum, Universitaetsstr. 150, 44801 Bochum (Germany); Fornari, R. [Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin (Germany)

    2011-10-31

    The liquid-delivery spin metal-organic chemical vapor phase deposition method was used to grow epitaxial sodium-bismuth-titanate films of the system Bi{sub 4}Ti{sub 3}O{sub 12} + xNa{sub 0.5}Bi{sub 0.5}TiO{sub 3} on SrTiO{sub 3}(001) substrates. Na(thd), Ti(O{sup i}Pr){sub 2}(thd){sub 2} and Bi(thd){sub 3}, solved in toluene, were applied as source materials. Depending on the substrate temperature and the Na/Bi ratio in the gas phase several structural phases of sodium-bismuth-titanate were detected. With increasing temperature and/or Na/Bi ratio, phase transitions from an Aurivillius phase with m = 3 to m = 4 via an interleaved state with m = 3.5, and, finally, to Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} with perovskite structure (m = {infinity}) were established. These phase transitions proceed at remarkably lower temperatures than in ceramics or bulk crystals for which they had been exclusively observed so far.

  12. Deposition of Visible Light Active Photocatalytic Bismuth Molybdate Thin Films by Reactive Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Marina Ratova

    2016-01-01

    Full Text Available Bismuth molybdate thin films were deposited by reactive magnetron co-sputtering from two metallic targets in an argon/oxygen atmosphere, reportedly for the first time. Energy dispersive X-ray spectroscopy (EDX analysis showed that the ratio of bismuth to molybdenum in the coatings can be effectively controlled by varying the power applied to each target. Deposited coatings were annealed in air at 673 K for 30 min. The crystalline structure was assessed by means of Raman spectroscopy and X-ray diffraction (XRD. Oxidation state information was obtained by X-ray photoelectron spectroscopy (XPS. Photodegradation of organic dyes methylene blue and rhodamine B was used for evaluation of the photocatalytic properties of the coatings under a visible light source. The photocatalytic properties of the deposited coatings were then compared to a sample of commercial titanium dioxide-based photocatalytic product. The repeatability of the dye degradation reactions and photocatalytic coating reusability are discussed. It was found that coatings with a Bi:Mo ratio of approximately 2:1 exhibited the highest photocatalytic activity of the coatings studied; its efficacy in dye photodegradation significantly outperformed a sample of commercial photocatalytic coating.

  13. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    International Nuclear Information System (INIS)

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N2 atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H2 (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K2) that of the thin films treated with EB irradiation alone

  14. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp; Kurita, Kensuke [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Hagino, Harutoshi; Miyazaki, Koji [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu 804-8550 (Japan); Tanaka, Saburo [Department of Mechanical Engineering, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)

    2015-08-14

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N{sub 2} atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H{sub 2} (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K{sup 2}) that of the thin films treated with EB irradiation alone.

  15. Determination of Sb(III) using an ex-situ bismuth screen-printed carbon electrode by adsorptive stripping voltammetry.

    Science.gov (United States)

    Rojas-Romo, Carlos; Serrano, Núria; Ariño, Cristina; Arancibia, Verónica; Díaz-Cruz, José Manuel; Esteban, Miquel

    2016-08-01

    The determination of Sb(III) on an ex-situ bismuth screen-printed carbon electrode (ex-situ BiSPCE) by means of adsorptive stripping voltammetry (AdSV) using quercetin-5'-sulfonic acid as chelating agent was optimized. The effect of different experimental parameters such pH, ligand concentration (CQSA), accumulation potential (Eacc) and accumulation time (tacc) were studied to obtain a wide linear range, the highest sensitivity and the lowest detection limit. Ex-situ BiSPCE was analytically compared with a sputtered bismuth screen-printed electrode (BispSPE) under optimal conditions. The obtained analytical parameters suggest that ex-situ BiSPCE behaves much better than BispSPE and the first was selected for this study. Optimal parameters were pH=4.6; CQSA=10.0 to 20.0×10(-6)molL(-1); Eacc=-0.5V and tacc=60s. Peak area is proportional to Sb(III) concentration up to 100.0μgL(-1) (tacc 60s) and 45.0μgL(-1) (tacc 120s) range, with detection limits of 1.2μgL(-)(1) (tacc 60s) and 0.8μgL(-1) (tacc 120s). The relative standard deviation for a Sb(III) solution (20.0μgL(-1)) was 3.9% for ten successive assays. Thus, the effect of various interfering metal ions was studied and the methodology was validated using a spiked groundwater reference material with very satisfactory results. PMID:27216652

  16. Si film electrodes prepared on discontinuous current collector

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Gyu-bong; Im, Yeon-min; Lee, Won-rak; Lee, Sang-hun; Ji, Seong- yong [School of Materials Science and Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Gazwadong 900, Jinju, Gyeongnam 660-701 (Korea, Republic of); Kim, Guk-tae [Institute of Physical Chemistry, MEET Battery Research Center, Corrensstr 46, 48149 Münster (Germany); Nam, Tae-hyun [School of Materials Science and Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Gazwadong 900, Jinju, Gyeongnam 660-701 (Korea, Republic of); Kim, Ki-won, E-mail: kiwonkim@gnu.ac.kr [School of Materials Science and Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Gazwadong 900, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-11-01

    Discontinuous Si film electrodes with 400, 800, and 1700 μm discontinuous lines (break lines) were fabricated by a simple masking and etching process. The structural and electrochemical properties of continuous and discontinuous Si film electrodes were investigated by means of optical microscopy, field emission scanning electron microscopy, X-ray diffraction, and charge–discharge tests. Although all electrodes showed similar first-charge capacities in the range of 210–230 μAh/g, the discontinuous electrode exhibited improved coulombic efficiency and cyclability when compared to the continuous electrode. Up to 100 cycles, the discontinuous electrode with the shortest line distance of 400 μm demonstrated the highest efficiency (95.2%) and capacity retention (89%). Observation of the cycled Si film electrodes revealed that discontinuity enhanced the structural stability of the electrode during the charge–discharge process. - Highlights: • Si film electrodes with various distances between discontinuous lines were fabricated. • The discontinuous electrode improved coulombic efficiency and cycleability. • The discontinuous line in the Si film electrode enhanced the structural stability.

  17. Potentiometric stripping analysis of bismuth based on carbon paste electrode modified with cryptand [2.2.1] and multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    An electrochemical method based on potentiometric stripping analysis (PSA) employing a cryptand [2.2.1] (CRY) and carbon nanotube (CNT) modified paste electrode (CRY-CNT-PE) has been proposed for the subnanomolar determination of bismuth. The characterization of the electrode surface has been carried out by means of scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronocoulometry (CC). It was observed that by employing CRY-CNT-PE, a 9-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (s/V) was proportional to the Bi(III) concentration in the range of 5.55 x 10-8 to 9.79 x 10-11 M (r = 0.9990) with the detection limit (S/N = 3) of 3.17 x 10-11 M. The practical analytical utilities of the modified electrode were demonstrated by the determination of bismuth in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as a simple preparation method, high sensitivity, very low detection limits and excellent reproducibility. Moreover, the results obtained for bismuth analysis in commercial and real samples using CRY-CNT-PE and those obtained by atomic absorption spectroscopy (AAS) are in agreement at the 95% confidence level.

  18. Preparation of bismuth telluride thin film by electrochemical atomic layer epitaxy(ECALE)

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Junyou; GAO Xianhui; HOU Jie; BAO Siqian; FAN Xian

    2007-01-01

    Thin-layer electrochemical studies of the underpotential deposition(UPD)of Bi and Te on cold rolled silver substrate have been performed.The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and Bi UPD on Te-covered Ag fitted UPD dynamics mechanism.A thin film of bismuth telluride was formed by alternately depositing Te and Bi via an automated flow deposition system.X-ray diffraction indicated the deposits of Bi2Te3.Energy Dispersive X-ray Detector quantitative analysis gave a 2:3 stoichiornetric ratio of Bi to Te,which was consistent with X-ray Diffraction results.Electron probe microanalysis of the deposits showed a network structure that results from the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit.

  19. Surface Landau levels and spin states in bismuth (111) ultrathin films.

    Science.gov (United States)

    Du, Hongjian; Sun, Xia; Liu, Xiaogang; Wu, Xiaojun; Wang, Jufeng; Tian, Mingyang; Zhao, Aidi; Luo, Yi; Yang, Jinlong; Wang, Bing; Hou, J G

    2016-03-11

    The development of next-generation electronics is much dependent on the discovery of materials with exceptional surface-state spin and valley properties. Because of that, bismuth has attracted a renewed interest in recent years. However, despite extensive studies, the intrinsic electronic transport properties of Bi surfaces are largely undetermined due to the strong interference from the bulk. Here we report the unambiguous determination of the surface-state Landau levels in Bi (111) ultrathin films using scanning tunnelling microscopy under magnetic fields perpendicular to the surface. The Landau levels of the electron-like and the hole-like carriers are accurately characterized and well described by the band structure of the Bi (111) surface from density functional theory calculations. Some specific surface spin states with a large g-factor are identified. Our findings shed light on the exploiting surface-state properties of Bi for their applications in spintronics and valleytronics.

  20. Three-electrode current-voltage measurements on erbia-stabilized bismuth oxide with sputtered noble metal electrodes

    NARCIS (Netherlands)

    Vinke, I.C.; Boukamp, B.A.; Vries, de K.J.; Burggraaf, A.J.

    1992-01-01

    The anodic and cathodic polarization behaviour of sputtered porous gold electrodes on (Bi2O3)0.75(Er2O3)0.25 (abbreviated BE25) was studied as function of temperature and oxygen partial pressure using a three-electrode cell. The anodic polarization is smaller than the cathodic polarization, allowing

  1. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing.

    Science.gov (United States)

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-19

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson-Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm(-1) K(-2)), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance. PMID:27389820

  2. Structural, optical, and transport properties of nanocrystalline bismuth telluride thin films treated with homogeneous electron beam irradiation and thermal annealing

    Science.gov (United States)

    Takashiri, Masayuki; Asai, Yuki; Yamauchi, Kazuki

    2016-08-01

    We investigated the effects of homogeneous electron beam (EB) irradiation and thermal annealing treatments on the structural, optical, and transport properties of bismuth telluride thin films. Bismuth telluride thin films were prepared by an RF magnetron sputtering method at room temperature. After deposition, the films were treated with homogeneous EB irradiation, thermal annealing, or a combination of both the treatments (two-step treatment). We employed Williamson–Hall analysis for separating the strain contribution from the crystallite domain contribution in the x-ray diffraction data of the films. We found that strain was induced in the thin films by EB irradiation and was relieved by thermal annealing. The crystal orientation along c-axis was significantly enhanced by the two-step treatment. Scanning electron microscopy indicated the melting and aggregation of nano-sized grains on the film surface by the two-step treatment. Optical analysis indicated that the interband transition of all the thin films was possibly of the indirect type, and that thermal annealing and two-step treatment methods increased the band gap of the films due to relaxation of the strain. Thermoelectric performance was significantly improved by the two-step treatment. The power factor reached a value of 17.2 μW (cm‑1 K‑2), approximately 10 times higher than that of the as-deposited thin films. We conclude that improving the crystal orientation and relaxing the strain resulted in enhanced thermoelectric performance.

  3. Direct Growth of Bismuth Film as Anode for Aqueous Rechargeable Batteries in LiOH, NaOH and KOH Electrolytes

    Directory of Open Access Journals (Sweden)

    Wenhua Zuo

    2015-10-01

    Full Text Available As promising candidates for next-generation energy storage devices, aqueous rechargeable batteries are safer and cheaper than organic Li ion batteries. But due to the narrow voltage window of aqueous electrolytes, proper anode materials with low redox potential and high capacity are quite rare. In this work, bismuth electrode film was directly grown by a facile hydrothermal route and tested in LiOH, NaOH and KOH electrolytes. With low redox potential (reduction/oxidation potentials at ca. −0.85/−0.52 V vs. SCE, respectively and high specific capacity (170 mAh·g−1 at current density of 0.5 A·g−1 in KOH electrolyte, Bi was demonstrated as a suitable anode material for aqueous batteries. Furthermore, by electrochemical impedance spectroscopy (EIS analysis, we found that with smaller Rs and faster ion diffusion coefficient, Bi electrode film in KOH electrolyte exhibited better electrochemical performance than in LiOH and NaOH electrolytes.

  4. Bismuth induced enhanced green emission from terbium ions and their complex in thin films.

    Science.gov (United States)

    Kaur, Gagandeep; Kumar, Brijesh; Verma, R K; Rai, S B

    2014-07-28

    Bismuth nanoparticles (NPs) have been prepared by the pulsed laser ablation technique using the third harmonics of a Nd-YAG laser. UV-absorption and TEM micrographs show Bi NPs of spherical shape with the average particle size ranging from 15 to 20 nm. These NPs were dispersed with Tb(3+) ions and their complex with salicylic acid (Sal) in polyvinyl alcohol to obtain thin films. The influence of Bi NPs on the emissive properties of Tb(3+) ions and the [Tb(Sal)3(phen)] complex has been studied by luminescence spectroscopy using 266 nm and 355 nm as excitation wavelengths. The luminescence intensity of Tb(3+) ions complexed with Sal in the thin polymer films increased significantly as compared to the Tb(3+) ions in the presence of Bi NPs on excitation at 355 nm. However, terbium ions in the case of the [Tb(Sal)3(phen)] complex together with NPs show an intense and extended emission spectrum in the 375-700 nm range for transitions arising from (5)D3 and (5)D4 levels to different (7)F(J) levels on 266 nm excitation. The luminescence enhancement has also been supported by lifetime measurements.

  5. Direct evidence for the spin cycloid in strained nanoscale bismuth ferrite thin films

    Science.gov (United States)

    Bertinshaw, Joel; Maran, Ronald; Callori, Sara J.; Ramesh, Vidya; Cheung, Jeffery; Danilkin, Sergey A.; Lee, Wai Tung; Hu, Songbai; Seidel, Jan; Valanoor, Nagarajan; Ulrich, Clemens

    2016-09-01

    Magnonic devices that utilize electric control of spin waves mediated by complex spin textures are an emerging direction in spintronics research. Room-temperature multiferroic materials, such as bismuth ferrite (BiFeO3), would be ideal candidates for this purpose. To realize magnonic devices, a robust long-range spin cycloid with well-known direction is desired, since it is a prerequisite for the magnetoelectric coupling. Despite extensive investigation, the stabilization of a large-scale uniform spin cycloid in nanoscale (100 nm) thin BiFeO3 films has not been accomplished. Here, we demonstrate cycloidal spin order in 100 nm BiFeO3 thin films through the careful choice of crystallographic orientation, and control of the electrostatic and strain boundary conditions. Neutron diffraction, in conjunction with X-ray diffraction, reveals an incommensurate spin cycloid with a unique [11] propagation direction. While this direction is different from bulk BiFeO3, the cycloid length and Néel temperature remain equivalent to bulk at room temperature.

  6. Study for Electrode Metals on Taste Sensor with LB film

    Science.gov (United States)

    Yokoya, Takahiro; Hirata, Takamichi; Akiya, Masahiro

    In this paper, sensor responses with only metal electrode as Au, Cr, Ti and more with LB film were described. LB film material was the Dioctadecyldimethylammonium bromide combined by PVSK as an underlayer. To detect five basic taste substances, sensor parameters were defined as maximum voltage change and response time. Response time for sourness and umami with Ti and Cr evaporated metal electrode was larger than that of usual Au electrode. LB film effect was finally found to increase response time for five basic taste materials.

  7. Structural, morphology and electrical studies on ferroelectric bismuth titanate thin films prepared by sol?gel technique

    Science.gov (United States)

    Giridharan, N. V.; Madeswaran, S.; Jayavel, R.

    2002-04-01

    Crystal structure, surface morphology, compositional homogeneity and electrical properties of layered perovskite bismuth titanate (BTO) thin films have been investigated. BTO thin films were deposited on silicon and platinum-coated silicon substrates by spin coating. X-ray diffraction analysis confirms that the crystallinity of the films increases with increasing annealing temperature and the optimum temperature is found to be 600°C. Morphology studies by AFM showed that the surface of the films were smooth, dense and crack free. Composition analysis on the surface and in-depth confirms the stoichiometry of the films. C- V measurements show a counter-clockwise dielectric hysteresis, indicating that the ferroelectric property sufficiently controls the silicon potential with a memory width of 2 V. The leakage current density of the films is measured to be 2×10 -7 A/cm 2 from I- V characteristics at an applied voltage of 1 V.

  8. Microstructure, morphology, adhesion and tribological behavior of sputtered niobium carbide and bismuth films on tool steel

    Directory of Open Access Journals (Sweden)

    Laura Angélica Ardila Rodríguez

    2014-11-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE AR-SA Normal 0 21 false false false ES-CO X-NONE AR-SA NbC, Bi and Bi/NbC coatings were deposited on AISI M2 steel substrates using unbalanced magnetron sputtering at room temperature with zero bias voltage. Were studied the phase structure, the morphology, the adhesion and the tribological behavior of the three coatings. The niobium carbide film crystallized in the NbC cubic structure, and the bismuth layers had a rhombohedral phase with random orientation. The NbC coating had a smooth surface with low roughness, while the Bi layers on steel and on NbC coating had higher roughness and a morphology composed of large particles. By using a ductile Nb interlayer good adhesion between the NbC coating and the steel substrate was achieved. The Bi coating had better adhesion with the NbC layer than with the steel substrate. The tribological performance of the Bi coating on steel was not satisfactory, but according to the preliminary results, the produced NbC and Bi/NbC coatings have the potential to improve the tribological performance of the steel.

  9. Film stresses and electrode buckling in organic solar cells

    KAUST Repository

    Brand, Vitali

    2012-08-01

    We investigate the film stresses that develop in the polymer films and metal electrodes of poly(3-hexyl thiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic solar cells. A compressive biaxial stress of ∼-36 MPa was measured in PEDOT:PSS while a tensile stress of ∼6 MPa was measured in the BHJ layer. We then analyze the effect of electrode deposition rate on the film stresses in the Al electrode. Compressive stresses of ∼-100 to -145 MPa in the Al electrode lead to a buckling instability resulting in undulating electrode surface topography. The BHJ layer was found to have the lowest cohesion (∼1.5-1.8 J/m 2) among the layers of the solar cell and dependent on the Al electrode deposition rate. The cohesive failure path in the BHJ layer exhibited the same periodicity and orientation of the Al electrode buckling topography. We discuss the implications of the film stresses on damage processes during device fabrication and operation. © 2012 Elsevier B.V. All rights reserved.

  10. HIGHLY SENSITIVE CATALASE ELECTRODE BASED ON POLYPYRROLE FILMS WITH MICROCONTAINERS

    Institute of Scientific and Technical Information of China (English)

    Yu-ying Gao; Gao-quan Shi

    2006-01-01

    Highly sensitive catalase electrodes for sensing hydrogen peroxide have been fabricated based on polypyrrole films with microcontainers. The microcontainers have a cup-like morphology and are arranged in a density of 4000 units cm-2.Catalase was immobilized into the polypyrrole films with microcontainers (Ppy-mc), which were coated on a Pt substrate electrode. The catalase/Ppy-mc/Pt electrode showed linear response to hydrogen peroxide in the range of 0-18 mmol/L at a potential of -0.3 V (versus SCE). Its sensitivity was measured to be approximately 3.64 μA (mmol/L)-1 cm-2, which is about two times that of the electrode fabricated from a flat Ppy film (catalase/Ppy-flat/Pt electrode). The electrode is highly selective for hydrogen peroxide and its sensitivity is interfered by potential interferents such as ascorbic acid, urea and fructose. Furthermore, such catalase electrodes showed long-term storage stability of 15 days under dry conditions at 4℃.

  11. Synthesis and materials chemistry of bismuth tris-(di-i-propylcarbamate): deposition of photoactive Bi2O3 thin films.

    Science.gov (United States)

    Cosham, Samuel D; Hill, Michael S; Horley, Graeme A; Johnson, Andrew L; Jordan, Laura; Molloy, Kieran C; Stanton, David C

    2014-01-01

    The bismuth carbamate Bi(O2CNPr(i)2)3, a tetramer in the solid-state, has been synthesized and used to deposit mixtures of bismuth oxides by aerosol-assisted chemical vapor deposition (AACVD). The nature of the deposited oxide is a function of both temperature and run-time. Initially, δ-Bi2O3 is deposited, over which grows a thick layer of β-Bi2O3 nanowires, the latter having an increasing degree of preferred orientation at higher deposition temperatures. The photocatalytic activity of a thin film of δ-Bi2O3 for the degradation of methylene blue dye was found to be similar to that of a commercial TiO2 film on glass, while the film overcoated with β-Bi2O3 nanowires was less active. Exposure of Bi(O2CNPr(i)2)3 to controlled amounts of moist air affords the novel oxo-cluster Bi8(O)6(O2CNPr(i)2)12, whose structure has also been determined. PMID:24387747

  12. Efficient Water-Splitting Device Based on a Bismuth Vanadate Photoanode and Thin-Film Silicon Solar Cells

    OpenAIRE

    Han, Lihao; Abdi, Fatwa F.; Van De Krol, Roel; Liu, Rui; Huang, Zhuangqun; Lewerenz, Hans-Joachim; Dam, Bernard; Zeman, Miro; Arno H. M. Smets

    2014-01-01

    A hybrid photovoltaic/photoelectrochemical (PV/PEC) water-splitting device with a benchmark solar-to-hydrogen conversion efficiency of 5.2 % under simulated air mass (AM) 1.5 illumination is reported. This cell consists of a gradient-doped tungsten–bismuth vanadate (W:BiVO_4) photoanode and a thin-film silicon solar cell. The improvement with respect to an earlier cell that also used gradient-doped W:BiVO4 has been achieved by simultaneously introducing a textured substrate to enhance light t...

  13. Method for producing thin film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, Manoj; Ma, Beihai; Balachandran, Uthamalingam; Dorris, Stephen

    2016-06-07

    The invention provides for A method for producing pure phase strontium ruthenium oxide films, the method comprising solubilizing ruthenium-containing and strontium-containing compounds to create a mixture; subjecting the mixture to a first temperature above that necessary for forming RuO.sub.2 while simultaneously preventing formation of RuO.sub.2; maintaining the first temperature for a time to remove organic compounds from the mixture, thereby forming a substantially dry film; and subjecting the film to a second temperature for time sufficient to crystallize the film. Also provided is pure phase material comprising strontium ruthenium oxide wherein the material contains no RuO.sub.2.

  14. Mercury film electrodes: developments, trends and potentialities for electroanalysis.

    Science.gov (United States)

    Economou, A; Fielden, P R

    2003-03-01

    In this article, the field of mercury film electrodes (MFE's) as electroanalytical devices is reviewed. Special emphasis is placed on the area of new materials as substrates for the mercury coating and the mercury plating process as well as on the developments related to the electrode modification used to achieve an increase in either the selectivity and/or the sensitivity of the analysis. Other topics discussed are microelectrodes, disposable electrodes and some novel, innovative or less well explored applications of electroanalytical methods using MFE's. The future prospects, potential uses and alternatives for MFE's in electroanalysis are finally discussed.

  15. Comprehensive dielectric performance of bismuth acceptor doped BaTiO3 based nanocrystal thin film capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, SY; Zhang, HN; Sviridov, L; Huang, LM; Liu, XH; Samson, J; Akins, D; Li, J; O' Brien, S

    2012-11-07

    We present a novel approach to preparing bismuth acceptor doped barium titanate nanocrystal formulations that can be deposited in conjunction with polymers in order to prepare a thin film nanocomposite dielectric that exhibits desirable capacitor characteristics. Exploring the limits of dielectric function in nanocomposites is an important avenue of materials research, while paying strict attention to the overall device quality, namely permittivity, loss and equivalent series resistance (ESR). Pushing capacitor function to higher frequencies, a desirable goal from an electrical engineering point of view, presents a new set of challenges in terms of minimizing interfacial, space charge and polarization effects within the dielectric. We show the ability to synthesize BaTi0.96Bi0.04O3 or BaTi0.97Bi0.03O3 depending on nominal molar concentrations of bismuth at the onset. The low temperature solvothermal route allows for substitution at the titanium site (strongly supported by Rietveld and Raman analysis). Characterization is performed by XRD with Rietveld refinement, Raman Spectroscopy, SEM and HRTEM. A mechanism is proposed for bismuth acceptor substitution, based on the chemical reaction of the alkoxy-metal precursors involving nucleophilic addition. Dielectric analysis of the nanocrystal thin films is performed by preparing nanocrystal/PVP 2-2 nanocomposites (no annealing) and comparing BaTi0.96Bi0.04O3 and BaTi0.97Bi0.03O3 with undoped BaTiO3. Improvements of up to 25% in capacitance (permittivity) are observed, with lower loss and dramatically improved ESR, all to very high frequency ranges (>10 MHz).

  16. Tungsten oxide in polymer electrolyte fuel cell electrodes-A thin-film model electrode study

    Energy Technology Data Exchange (ETDEWEB)

    Wickman, Bjoern, E-mail: bjorn.wickman@chalmers.s [Competence Centre for Catalysis, Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Wesselmark, Maria; Lagergren, Carina; Lindbergh, Goeran [Applied Electrochemistry, School of Chemical Science and Engineering, KTH, SE-100 44 Stockholm (Sweden)

    2011-10-30

    Highlights: > Platinum and tungsten oxide thin-film electrocatalysts. > Single cell fuel cell evaluation. > Hydrogen-tungsten bronze formation. > CO oxidation on platinum on tungsten oxide. - Abstract: Thin films of WO{sub x} and Pt on WO{sub x} were evaporated onto the microporous layer of a gas diffusion layer (GDL) and served as model electrodes in the polymer electrolyte fuel cell (PEFC) as well as in liquid electrolyte measurements. In order to study the effects of introducing WO{sub x} in PEFC electrodes, precise amounts of WO{sub x} (films ranging from 0 to 40 nm) with or without a top layer of Pt (3 nm) were prepared. The structure of the thin-film model electrodes was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy prior to the electrochemical investigations. The electrodes were analyzed by cyclic voltammetry and the electrocatalytic activity for hydrogen oxidation reaction (HOR) and CO oxidation was examined. The impact of Nafion in the electrode structure was examined by comparing samples with and without Nafion solution sprayed onto the electrode. Fuel cell measurements showed an increased amount of hydrogen tungsten bronzes formed for increasing WO{sub x} thicknesses and that Pt affected the intercalation/deintercalation process, but not the total amount of bronzes. The oxidation of pre-adsorbed CO was shifted to lower potentials for WO{sub x} containing electrodes, suggesting that Pt-WO{sub x} is a more CO-tolerant catalyst than Pt. For the HOR, Pt on thicker films of WO{sub x} showed an increased limiting current, most likely originating from the increased electrochemically active surface area due to proton conductivity and hydrogen permeability in the WO{sub x} film. From measurements in liquid electrolyte it was seen that the system behaved very differently compared to the fuel cell measurements. This exemplifies the large differences between the liquid electrolyte and fuel cell systems. The thin-film model

  17. Electrochemical co-detection of As(III), Hg(II) and Pb(II) on a bismuth modified exfoliated graphite electrode.

    Science.gov (United States)

    Mafa, Potlako J; Idris, Azeez O; Mabuba, Nonhlangabezo; Arotiba, Omotayo A

    2016-06-01

    The applicability of a bismuth modified exfoliated graphite (EG) electrode for the co-detection of heavy metal ions -As(III), Hg(II) and Pb(II)-in water samples using square wave anodic stripping voltammetry (SWASV) is reported. Bismuth nanoparticles were deposited on an EG electrode potentiostatically at -1000mV for 300s to form EG-Bi electrode. The Bi modified EG electrode was characterised in 5mM ferrocene and used to as an electrochemical sensor for Pb(II) and Hg(II) individually in 0.1M acetate buffer solution (pH 5) with detection limits (LODs) of 0.83μgL(-1)., 0.46μgL(-1) and limit of quantification of 2.8μgL(-1) and 1.5μgL(-1) respectively. Simultaneous detection of Pb(II), As(III) and Hg(II) was also performed with LODs of 0.053μgL(-1), 0.014μgL(-1), 0.081μgL(-1) and LOQs of 0.18μgL(-1), 0.047μgL(-1) and 0.27μgL(-1) for Pb(II), As(III) and Hg(II) respectively. All the detections were performed under optimised experimental conditions. The stability of the EG-Bi sensor was tested and the electrode was applied to environmental samples. The results found with this method were comparable with those obtained with inductively coupled plasma - optical emission spectrometric technique.

  18. Electrochemical co-detection of As(III), Hg(II) and Pb(II) on a bismuth modified exfoliated graphite electrode.

    Science.gov (United States)

    Mafa, Potlako J; Idris, Azeez O; Mabuba, Nonhlangabezo; Arotiba, Omotayo A

    2016-06-01

    The applicability of a bismuth modified exfoliated graphite (EG) electrode for the co-detection of heavy metal ions -As(III), Hg(II) and Pb(II)-in water samples using square wave anodic stripping voltammetry (SWASV) is reported. Bismuth nanoparticles were deposited on an EG electrode potentiostatically at -1000mV for 300s to form EG-Bi electrode. The Bi modified EG electrode was characterised in 5mM ferrocene and used to as an electrochemical sensor for Pb(II) and Hg(II) individually in 0.1M acetate buffer solution (pH 5) with detection limits (LODs) of 0.83μgL(-1)., 0.46μgL(-1) and limit of quantification of 2.8μgL(-1) and 1.5μgL(-1) respectively. Simultaneous detection of Pb(II), As(III) and Hg(II) was also performed with LODs of 0.053μgL(-1), 0.014μgL(-1), 0.081μgL(-1) and LOQs of 0.18μgL(-1), 0.047μgL(-1) and 0.27μgL(-1) for Pb(II), As(III) and Hg(II) respectively. All the detections were performed under optimised experimental conditions. The stability of the EG-Bi sensor was tested and the electrode was applied to environmental samples. The results found with this method were comparable with those obtained with inductively coupled plasma - optical emission spectrometric technique. PMID:27130095

  19. Spray deposited titanium oxide thin films as passive counter electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, P.S.; Mujawar, S.H.; Inamdar, A.I.; Patil, P.S. [Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur-416004 (India); Deshmukh, H.P. [Bharati Vidyapeeth Deemed University, Yashwantrao Mohite College, Pune-411038 (India)

    2007-02-15

    Titanium dioxide (TiO{sub 2}) thin films were deposited from methanolic solution onto fluorine doped tin oxide coated conducting glass substrates by spray pyrolysis technique. The electrochemical properties of TiO{sub 2} thin films were investigated using cyclic voltammetry, chronoamperometry, chronocoulometry and iono-optical studies, in 0.1N H{sub 2}SO{sub 4} electrolyte. Performance of the films deposited at three different substrate temperatures, viz. 350, 400 and 450 C is discussed in view of their utilization in electrochromic devices, as counter electrode. The magnitude of charge storage capacity, Q/t (4.75-6.13 x 10{sup -3} mC/(cm{sup 2} nm)) and colouration efficiency (3.2-4.3 cm{sup 2}/mC) of TiO{sub 2} rank these films among the promising counter electrodes in electrochromic devices. (author)

  20. Growth and characterization of bismuth selenide thin films by chemical vapor deposition

    Science.gov (United States)

    Brom, Joseph E.

    Topological insulators are a recently discovered class of materials that have garnered much interest due to their unique surface states. With its relatively high band gap (0.3eV) and nearly ideal band structure, Bi2Se 3 has been a primary material of interest in the study of topological insulating behavior. However, several factors have made this study difficult. Bi2Se3 typically has a high native selenium vacancy concentration, and selenium vacancies act as donors in the material, leading to a high bulk electron concentration. The surface of Bi2Se 3 has also been shown to be susceptible to environmental doping when exposed to ambient air. Combining these two factors means that Bi2Se 3 is usually highly n-type doped, making it difficult to study the surface conducting states by transport measurements. This study investigated the use of two different chemical vapor deposition (CVD) techniques for the growth of Bi2Se3 thin films on sapphire (001): hybrid physicalchemical vapor deposition (HPCVD) and metal-organic chemical vapor deposition (MOCVD). HPCVD is a process which combines the evaporation of elemental selenium with the thermal decomposition of trimethylbismuth (TMBi). The use of elemental selenium immediately around the substrate provides a high overpressure of selenium, allowing for reduction of the selenium vacancy concentration. Bi2Se3 films grown on sapphire were epitaxial and highly oriented parallel to the substrate giving rise to narrow X-ray rocking curves (full-width-at-half-maximum=160 arcsecs for (006) reflection) and 6-fold rotational symmetry as determined by phi scans. The structural properties were consistent with deposition via a van der Waals epitaxy process. The selenium to bismuth ratio (VI/V) ratio proved important for achieving a reduced electron concentration of TMBi) dimethylselenide (DMSe) as precursors. Epitaxial Bi 2Se3 films were also produced by MOCVD on sapphire, however, the electron concentrations were generally higher (1- 3x

  1. Nanocalorimetry of bismuth nanoparticles

    Science.gov (United States)

    Olson, Eric Ashley

    The properties of nanosized bismuth particles are investigated using a nanocalorimetric technique. A brief description of the experimental method and data analysis procedures is reported. Bismuth nanoparticles are found to melt at a temperature below that of bulk material, but higher than expected using the standard model. Also included is the results of a finite element analysis and simulated melting of bismuth films on various kinds of sensors. Temperature distributions are found to be nonuniform for calorimetric sensors with Al metallizations, but much more uniform for Pt metallized sensors. The consequences of this nonuniformity on caloric data are discussed.

  2. Sputtering and surface topography modification of bismuth thin films under swift {sup 84}Kr{sup 15+} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mammeri, S. [Centre de Recherche Nucleaire d' Alger, CRNA, B.P. 399, 02 Bd. Frantz Fanon, Alger-Gare, Algiers (Algeria); Ouichaoui, S., E-mail: souchaoui@gmail.com [Universite des Sciences et de la Technologie H. Boumediene (USTHB), Faculte de Physique, Laboratoire SNIRM, B.P. 32, El-Alia, 16111 Bab Ezzouar, Algiers (Algeria); Ammi, H. [Centre de Recherche Nucleaire d' Alger, CRNA, B.P. 399, 02 Bd. Frantz Fanon, Alger-Gare, Algiers (Algeria); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, P.O. Box 1906, Bellville 7535 (South Africa); Dib, A. [Centre de Recherche Nucleaire d' Alger, CRNA, B.P. 399, 02 Bd. Frantz Fanon, Alger-Gare, Algiers (Algeria); Msimanga, M. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa)

    2012-12-01

    The sputtering and surface topography modification of bismuth thin films deposited onto Si substrates and irradiated by 27.5 MeV {sup 84}Kr{sup 15+} ions over the fluence range 10{sup 12}-10{sup 14} cm{sup -2} have been studied using three complementary techniques: Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM) and X-ray diffraction (XRD). The RBS analysis reveals a linear reduction of the initial thickness of the irradiated bismuth samples by {approx}4% up to 7% with increasing ion fluence corresponding to a mean sputtering yield of {approx}2.9 Multiplication-Sign 10{sup 2} at/ion. Besides, significant sample surface topography changes occur upon ion irradiation consisting in grain growth and surface roughening clearly pointed out by performed AFM and XRD analyses. Moreover, a close correlation is observed between the variations versus ion fluence of the measured sputtering yield and the determined Bi surface grain size and compressive strain. These moderate Bi surface effects are similar to those pointed out previously for thin films irradiated by MeV heavy ions. They can be mainly caused by inelastic electronic collision mechanisms taking place within the Bi material electronic stopping power regime below the threshold for latent track formation.

  3. Growth morphology and structure of bismuth thin films on GaSb(110)

    DEFF Research Database (Denmark)

    Gemmeren, T. van; Lottermoser, L.; Falkenberg, G.;

    1998-01-01

    Photoelectron spectroscopy, low-energy electron diffraction, scanning tunneling microscopy and surface X-ray diffraction were used to investigate the growth of thin layers of bismuth on GaSb(110). At submonolayer coverages, growth of two-dimensional islands occurs. A uniform (1 x I)-reconstructio...... that the (1 x 1)-phases formed by antimony and bismuth adsorbates on (110) surfaces of other III-V compound semiconductors are also described by the epitaxial continued layer model. (C) 1998 Elsevier Science B.V. All rights reserved....

  4. Voltammetry at the Thin-Film Mercury Electrode (TFME).

    Science.gov (United States)

    Pomeroy, R. S.; And Others

    1989-01-01

    Reviewed is the use of the Thin-Film Mercury Electrode for anodic stripping voltammetry, simple voltammetry of solution cations and cathodic stripping voltammetry for the determination of an environmentally important molecule, thiourea. The construction of a simple potentiostat and applications for student laboratory courses are included. (CW)

  5. Polyaniline-graphite composite film glucose oxidase electrode

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hai-hui; CHEN Hong; CHEN Jin-hua; KUANG Ya-fei

    2006-01-01

    A novel polyaniline-graphite composite film glucose oxidase (PGCF GOD) electrode was developed. The PGCF was synthesized by cyclic voltammetry method in 0.5 mol/L H2SO4 solution containing 1 g/L graphite powder and 0.2 mol/L aniline. The PGCF GOD electrode was prepared by doping GOD into the composite film. The morphology of the PGCF and the response property of the PGCF GOD electrode were investigated by scanning electron microscopy and electrochemical measurement,respectively. The results show that the PGCF has a porous and netty structure and the PGCF GOD electrode has excellent response property such as high sensitivity and short response time. Influences of pH value, temperature, glucose concentration and potential on the response current of the electrode were also discussed. The sensor has a maximum steady-state current density of 357.17 tA/cm2and an apparent Michaelis-Menten constant of 16.57 mmol/L. The maximum current response of the enzyme electrode occurs under the condition of pH 5.5, 0.8 V and 65 ℃.

  6. Growth of bismuth telluride thin film on Pt by electrochemical atomic layer epitaxy

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Jun-you; GAO Xian-hui; HOU Jie; ZHANG Tong-jun; CUI Kun

    2005-01-01

    An automated thin-layer flow cell electrodeposition system was developed for growing Bi2 Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt,this reductive Te underpotential deposition (UPD)/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4: 3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO2+ reduction excludes the possibility of Bi2 Te3 formation. X-ray photoelectron spectroscopy (XPS) analysis also reveals that the incomplete charge transfer in HTeO2+ occurs in Te direct deposition. The effective way of depositing Bi2 Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). A polycrystalline characteristic was confirmed by XRD. The 2 : 3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about 0.3 - 0.4 μm in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.

  7. Metal/Diamond Composite Thin-Film Electrodes: New Carbon Supported Catalytic Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Greg M. Swain, PI

    2009-03-10

    The DOE-funded research conducted by the Swain group was focused on (i) understanding structure-function relationships at boron-doped diamond thin-film electrodes, (ii) understanding metal phase formation on diamond thin films and developing electrochemical approaches for producing highly dispersed electrocatalyst particles (e.g., Pt) of small nominal particle size, (iii) studying the electrochemical activity of the electrocatalytic electrodes for hydrogen oxidation and oxygen reduction and (iv) conducting the initial synthesis of high surface area diamond powders and evaluating their electrical and electrochemical properties when mixed with a Teflon binder. (Note: All potentials are reported versus Ag/AgCl (sat'd KCl) and cm{sup 2} refers to the electrode geometric area, unless otherwise stated).

  8. High-relative-dielectric-constant bismuth-niobium-oxide films prepared using Nb-rich precursor solution

    Science.gov (United States)

    Ariga, Tomoki; Inoue, Satoshi; Matsumoto, Shin; Onoue, Masatoshi; Miyasako, Takaaki; Tokumitsu, Eisuke; Shimoda, Tatsuya

    2015-09-01

    Various ceramic materials have been developed for electronic devices. Bismuth-niobium-oxide (BNO) films prepared by a chemical solution deposition (CSD) method have the cubic pyrochlore phase, high relative dielectric constant, and low tangent loss (tan δ). We found that a BNO cubic pyrochlore crystal was Nb-rich, even though its pyrochlore formula is A2B2O7. The crystallization temperature of BNO increased with increasing Nb ratio. The relative dielectric constants of BNO films were related to the Nb ratio in the precursor solution. The dielectric constant of the BNO films was 250 when the Bi and Nb ratios in BNO precursor solutions were 4 and 6, respectively, and the sintering temperature was 600 °C. In addition, the tan δ was less than 0.01 at 1 kHz, which is higher than the reported values of BNO systems despite using the CSD method. These results show that the properties of BNO films prepared by the CSD method were associated with the Nb ratio in the precursor solution. Furthermore, the dielectric characteristics indicated that the Nb-rich BNO films have potential applications in electronic devices.

  9. Super-resolution readout property of bismuth-doped antimony-based thin film as a functional mask for read-only memory

    Science.gov (United States)

    Lu, Xinmiao; Wu, Yiqun; Wang, Yang; Wei, Jingsong

    2012-09-01

    Bismuth-doped antimony-based (Sb100- x Bi x , x=2.46) thin films were presented as a functional mask for super-resolution readout of read-only memory (ROM). The pit size of the ROM was 390 nm, and super-resolution readout was realized on a dynamic tester with laser wavelength of 780 nm and the numerical aperture of the focusing objective lens of 0.45. The carrier-to-noise ratio (CNR) of 22 dB, readout threshold power of 0.8 mW and super-resolution readout cycles of 2×104 was achieved. The influence of film thickness and readout power on CNR was investigated. The reflectivity and transmittance of the film with different temperature at wavelength of 780 nm were detected, and the super-resolution mechanism of the bismuth-doped antimony-based thin films as the functional mask layer was discussed.

  10. Electrochemical immunosensor based on bismuth nanocomposite film and cadmium ions functionalized titanium phosphates for the detection of anthrax protective antigen toxin.

    Science.gov (United States)

    Sharma, Mukesh K; Narayanan, J; Upadhyay, Sanjay; Goel, Ajay K

    2015-12-15

    Bacillus anthracis is a bioterrorism agent classified by the Centers for Disease Control and Prevention (CDC). Herein, a novel electrochemical immunosensor for the sensitive, specific and easy detection of anthrax protective antigen (PA) toxin in picogram concentration was developed. The immunosensor consists of (i) a Nafion-multiwall carbon nanotubes-bismuth nanocomposite film modified glassy carbon electrodes (BiNPs/Nafion-MWCNTs/GCE) as a sensing platform and (ii) titanium phosphate nanoparticles-cadmium ion-mouse anti-PA antibodies (TiP-Cd(2+)-MαPA antibodies) as signal amplification tags. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), thermogravimmetric analysis (TGA), Fourier transform-infra red spectroscopy (FT-IR), zeta-potential analysis, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to characterize the synthesized TiP nanoparticles and modified electrode surfaces. The immunosensing performance of BiNPs/Nafion-MWCNTs/GCE was evaluated based on sandwich immunoassay protocol. A square wave voltammetry (SWV) scan from -1.2 to -0.3 V in HAc-NaAc buffer solution (pH 4.6) without stripping process was performed to record the electrochemical responses at -0.75 V corresponding to high content of Cd(2+) ions loaded in TiP nanoparticles for the measurement of PA toxin. Under optimal conditions, the currents increased with increasing PA toxin concentrations in spiked human serum samples and showed a linear range from 0.1 ng/ml to 100 ng/ml. The limit of detection of developed immunosensor was found to be 50 pg/ml at S/N=3. The total time of analysis was 35 min. PMID:26148674

  11. Prebreakdown characteristics of thin film-coated molybdenum electrodes

    Energy Technology Data Exchange (ETDEWEB)

    He, P.; Sinha, M.K. (Department of Physics, North Dakota State University, Fargo, North Dakota 58105 (US))

    1989-12-15

    The effect of thin molybdenum films on molybdenum cathodes on the prebreakdown current between molybdenum electrodes in high vacuum has been studied. Films of four thicknesses: 10, 30, 100, and 300 A were used and the Fowler--Nordheim plots were made to determine the field enhancement factor {beta} and the electron emission area {ital a}. Maximum reduction of the prebreakdown current by a factor of 3000 was observed. The reduction in the current is a result of a decrease of both the field enhancement factor and the electron emission area of the cathode.

  12. CZTS thin films on transparent conducting electrodes by electrochemical technique

    International Nuclear Information System (INIS)

    We have fabricated single phase Cu2ZnSnS4 (CZTS) films using a specially designed 3-stage electrochemical system. Sequential electrodepositon of constituent metallic layers was carried out on SnO2/F coated glass substrates using a platinum counter electrode and a saturated calomel reference electrode. Unique bath compositions were formulated for each of these constituents. Sequentially deposited tri-layer stacks were annealed in sulfur environment to get CZTS phase. Detailed structural, morphological and optical characterization experiments were performed using several techniques including x-ray diffraction, Raman and UV–visible spectroscopy, scanning electron microscopy and atomic force microscopy. All characterization experiments indicated that the films are single phase with a measured direct band gap of 1.5 eV.

  13. Development of Bismuth-based Lead-free Piezoelectric Materials: Thin Film Piezoelectric Materials via PVD and CSD Routes

    Science.gov (United States)

    Jeon, Yu Hong

    Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems. Bismuth-based perovskite piezoelectric materials such as (Bi0.5,Na0.5)TiO3 - (Bi0.5K 0.5)TiO3 (BNT - BKT), (Bi0.5,Na0.5 )TiO3 - (Bi0.5K0.5)TiO3 - BaTiO3(BNT - BKT - BT), (Bi0.5K 0.5)TiO3 - Bi(Zn0.5,Ti0.5)O 3 (BKT - BZT), and (Bi0.5,Na0.5)TiO 3 - (Bi0.5K0.5)TiO3 - Bi(Mg 0.5,Ti0.5)O3 (BNT - BKT - BMgT) have been explored as potential alternatives to PZT. These materials systems have been extensively studied in bulk ceramic form, however many of the ultimate applications will be in thin film embodiments (i.e., microelectromechanical systems). For this reason, in this thesis these lead-free piezoelectrics are synthesized in thin film form to understand the structure-property-processing relationships and their impact on the ultimate device response. Fabrication of high quality of 0.95BKT - 0.05BZT thin films on platinized silicon substrates was attempted by pulsed laser deposition. Due to cation volatility, deposition parameters such as substrate temperature, deposition pressure, and target-substrate distance, as well as target overdoping were explored to achieve phase pure materials. This route led to high dielectric loss, indicative of poor ferroelectric behavior. This was likely a result of the poor thin film morphology observed in films deposited via this method. Subsequently, 0.8BNT - 0.2BKT, 85BNT - 10BKT - 5BT, and 72.5BNT - 22.5BKT - 5BMgT (near morphotropic phase boundary composition) were synthesized via chemical solution deposition. To compensate the loss of A-site cations, overdoped precursor solutions were prepared. Crystallization after each spin cast layer were required to

  14. Transferred metal electrode films for large-area electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jin-Guo [Department of Physics, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Medical Drive, Singapore S117456 (Singapore); Kam, Fong-Yu [Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); Chua, Lay-Lay [Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); Department of Physics, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore)

    2014-11-10

    The evaporation of metal-film gate electrodes for top-gate organic field-effect transistors (OFETs) limits the minimum thickness of the polymer gate dielectric to typically more than 300 nm due to deep hot metal atom penetration and damage of the dielectric. We show here that the self-release layer transfer method recently developed for high-quality graphene transfer is also capable of giving high-quality metal thin-film transfers to produce high-performance capacitors and OFETs with superior dielectric breakdown strength even for ultrathin polymer dielectric films. Dielectric breakdown strengths up to 5–6 MV cm{sup −1} have been obtained for 50-nm thin films of polystyrene and a cyclic olefin copolymer TOPAS{sup ®} (Zeon). High-quality OFETs with sub-10 V operational voltages have been obtained this way using conventional polymer dielectrics and a high-mobility polymer semiconductor poly[2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene-2,5-diyl]. The transferred metal films can make reliable contacts without damaging ultrathin polymer films, self-assembled monolayers and graphene, which is not otherwise possible from evaporated or sputtered metal films.

  15. Anthocyanin-sensitized solar cells using carbon nanotube films as counter electrodes

    Science.gov (United States)

    Zhu, Hongwei; Zeng, Haifeng; Subramanian, Venkatachalam; Masarapu, Charan; Hung, Kai-Hsuan; Wei, Bingqing

    2008-11-01

    Carbon nanotube (CNT) films have been used as counter electrodes in natural dye-sensitized (anthocyanin-sensitized) solar cells to improve the cell performance. Compared with conventional cells using natural dye electrolytes and platinum as the counter electrodes, cells with a single-walled nanotube (SWNT) film counter electrode show comparable conversion efficiency, which is attributed to the increase in short circuit current density due to the high conductivity of the SWNT film.

  16. Voltage-Induced Buckling of Dielectric Films using Fluid Electrodes

    CERN Document Server

    Tavakol, Behrouz

    2016-01-01

    Accurate and integrable control of different flows within microfluidic channels is crucial to further development of lab-on-a-chip and fully integrated adaptable structures. Here we introduce a flexible microactuator that buckles at a high deformation rate and alters the downstream fluid flow. The microactuator consists of a confined, thin, dielectric film that buckles into the microfluidic channel when exposed to voltage supplied through conductive fluid electrodes. We estimate the critical buckling voltage, and characterize the buckled shape of the actuator. Finally, we investigate the effects of frequency, flow rate, and the pressure differences on the behavior of the buckling structure and the resulting fluid flow. These results demonstrate that the voltage--induced buckling of embedded microstructures using fluid electrodes provides a means for high speed attenuation of microfluidic flow.

  17. Synthesis and Electrochemical Sensing Toward Heavy Metals of Bunch-like Bismuth Nanostructures

    Directory of Open Access Journals (Sweden)

    Zhang Zhi

    2009-01-01

    Full Text Available Abstract Large-scale bunch-like bismuth (Bi nanostructures were the first time to be synthesized via two-step electrochemical deposition. The growth mechanism of the nanostructures was discussed. Such a designed bunch-like Bi electrode has high sensitivity to detect the heavy metal ions due to its unique three-dimensional structures and strong ability of adsorbing the heavy metal ions. The bunch-like Bi electrode’s detection of heavy metals was statically performed using anodic stripping voltammetry (ASV. The detection in the Pb(II concentration range of 2.5–50 μg/l was also performed. Based on the experimental results, this bunch-like Bi electrode can be considered as an interesting alternative to common mercury electrodes and bismuth film electrodes for possible use in electrochemical studies and electroanalytical applications.

  18. Synthesis and Electrochemical Sensing Toward Heavy Metals of Bunch-like Bismuth Nanostructures

    Science.gov (United States)

    Zhang, Zhi; Yu, Ke; Bai, Dan; Zhu, Ziqiang

    2010-02-01

    Large-scale bunch-like bismuth (Bi) nanostructures were the first time to be synthesized via two-step electrochemical deposition. The growth mechanism of the nanostructures was discussed. Such a designed bunch-like Bi electrode has high sensitivity to detect the heavy metal ions due to its unique three-dimensional structures and strong ability of adsorbing the heavy metal ions. The bunch-like Bi electrode’s detection of heavy metals was statically performed using anodic stripping voltammetry (ASV). The detection in the Pb(II) concentration range of 2.5-50 μg/l was also performed. Based on the experimental results, this bunch-like Bi electrode can be considered as an interesting alternative to common mercury electrodes and bismuth film electrodes for possible use in electrochemical studies and electroanalytical applications.

  19. Cu(In,GaSe2 Thin Films Codoped with Sodium and Bismuth Ions for the Use in the Solar Cells

    Directory of Open Access Journals (Sweden)

    Fu-Shan Chen

    2015-01-01

    Full Text Available The codoping effects of sodium and bismuth ions on the characteristics of Cu(In,GaSe2 films prepared via the solution process were investigated in this study. When sodium and bismuth ions were incorporated into Cu(In,GaSe2, the ratio of the intensity of (112 diffraction peak to that of (220/204 diffraction peak was greatly increased. The codoping process not only enlarged the sizes of the grains in the films but also resulted in densification of the films. The carrier concentration of Cu(In,GaSe2 was found to be effectively increased to cause a reduction in the resistivity of the films. The above phenomena were attributed to the densified microstructures of the films and a decrease in the amount of the donor-type defects. The leakage current of the solar cells was found to be also decreased via the codoping process. Owing to the improved electrical properties of Cu(In,GaSe2 films, the conversion efficiency of the fabricated solar cells was significantly enhanced.

  20. BaPbO3 perovskite electrode for lead zirconate titanate ferroelectric thin films

    Science.gov (United States)

    Luo, Yih-Rong; Wu, Jenn-Ming

    2001-11-01

    BaPbO3 (BPO) films were prepared by rf-magnetron sputtering at temperatures as low as 350 °C. These films possessed low electrical resistivity of 1.4×10-3 Ω cm, which is appropriate for electrodes. The BPO electrode has an advantage over a Pt electrode in that it lowers the crystallization temperature of Pb(Zr0.53Ti0.47)O3 (PZT) films from 600 to 550 °C. The coercive fields of the PZT films deposited on a BPO/Pt electrode are significantly lower than those deposited on the Pt electrode, but the remanent polarization remained essentially unchanged. The BPO electrode also improved the fatigue resistance and decreased the leakage current of the PZT films deposited.

  1. Pr and Gd co-doped bismuth ferrite thin films with enhanced multiferroic properties

    Indian Academy of Sciences (India)

    Chang Chun Chen; Zi Xuan Liu; Gui Wang; Yi Lin Yan

    2014-12-01

    Pr and Gd co-modified Bi0.95−PrGd0.05FeO3 ( = 0.00, 0.05, 0.10) (BPGFO) thin films on Pt(111)/Ti/SiO2/Si(100) substrates were prepared by a sol-gel together with spin coating technique. A detailed study of electrical and magnetic properties of these thin films is reported. X-ray diffraction analysis shows that, with an increase in Pr content, the crystal structures of BPGFO thin films retain rhombohedral (R3c) symmetry accompanied by structure distortion. Polarization-electric field hysteresis loops of these thin films demonstrate that the incorporation of Pr and Gd into the Bi site of BiFeO3 thin film could enhance the ferroelectric performance. Compared to other thin films, the optimal ferroelectric behaviours in Bi0.85Pr0.1Gd0.05FeO3 thin film are ascribed to its large dielectric constant, low dissipation factor and low leakage current density. Room temperature magnetization-magnetic field curves of these thin films indicate that all the samples are of paramagnetic behaviours and the enhanced saturation magnetic properties can be found.

  2. A glassy carbon electrode modified with bismuth nanotubes in a silsesquioxane framework for sensing of trace lead and cadmium by stripping voltammetry

    International Nuclear Information System (INIS)

    Single-walled bismuth nanotubes (sw-BiNTs) were self-assembled with octa(3-aminopropyl) silsesquioxane as a framework and to govern morphology. Deposited on a glassy carbon electrode (GCE), the sw-BiNTs were used for the simultaneous analysis of Pb(II) and Cd(II) by square wave stripping voltammetry. The sw-BiNTs were prepared by (a) coordination interaction between the amino groups of the silsesquioxane and the Bi(III) ions, and by (b) reduction with sodium borohydride. Transmission electron microscopy images revealed single-walled tubular structures with diameters of ∼4–6 nm, and with lengths of several hundreds nanometers. GCEs modified with such sw-BiNTs perform much better than bare GCEs in stripping analysis of Pb(II) and Cd(II). The effects of adsorption quantity of sw-BiNTs, solution pH, pulse amplitude, and pulse width were optimized. The modified electrode was then used for the analysis of Pb(II) and Cd(II) in a linear response range from 0.4 to 6 μM with a sensitivity of 4.692 μA μM−1 and 3.835 μA μM−1, and detection limits of 1 nM and 5 nM, respectively. The method was successfully applied to the analysis of Pb(II) and Cd(II) in toy leachates, and the results were in good agreement with those obtained with atomic absorption spectrometry. Sensitivity and detection limits were compared with other voltammetric methods, and the sw-BiNTs are deemed to be an attractive alternative for practical applications. Other features of the electrode include low costs, a well reproducible nanostructure, and ease of scale-up of the fabrication process. (author)

  3. ELECTROANALYTICAL APPLICATIONS OF CARBOXYL-MODIFIED CARBON NANOTUBE FILM ELECTRODES

    Institute of Scientific and Technical Information of China (English)

    C.G. Hu; W.L. Wang; K.J. Liao; W. Zhu

    2003-01-01

    The electrochemical behavior of a carboxyl-modified carbon nanotube films was investigated to explore its possibility in electroanalytical applicaton. Cyclic voltammetry of quinone was conducted in 1mol/L Na2SO4, which showed a stable, quasi-reversible voltammetric response for quinone / hydroquinone, and the anodic and the cathodic peak potentials were 0.657V and -0.029V (vs. SCE) at a scan rate of 0.1V.s-1, respectively. Both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.01-0. 5 V.s-1, which suggested that the process of the electrode reactions was diffusion-controlled. Carboxyl-modified carbon nanotube electrodes made it possible to determine low level of dopamine selectively in the presence of a large excess of ascorbic acid in acidic media using derivative voltammetry.The results obtained were discussed in details. This work demonstrates the potential of carboxyl-modified carbon nanotube electrodes for electroanalytical applications.

  4. Electrochemical protection of thin film electrodes in solid state nanopores

    International Nuclear Information System (INIS)

    Solid state nanopores are a core element of next-generation single molecule tools in the field of nano-biotechnology. Thin film electrodes integrated into a pore can interact with charges and fields within the pore. In order to keep the nanopore open and thus functional electrochemically induced surface alteration of electrode surfaces and bubble formation inside the pore have to be eliminated. This paper provides electrochemical analyses of nanopores drilled into TiN membranes which in turn were employed as thin film electrodes. We studied physical pore integrity and the occurrence of water decomposition yielding bubble formation inside pores by applying voltages between - 4.5 and + 4.5 V to membranes in various protection stages continuously for up to 24 h. During potential application pores were exposed to selected electrolyte-solvent systems. We have investigated and successfully eliminated electrochemical pore oxidation and reduction as well as water decomposition inside nanopores of various diameters ranging from 3.5 to 25 nm in 50 nm thick TiN membranes by passivating the nanopores with a plasma-oxidized layer and using a 90% solution of glycerol in water as KCl solvent. Nanopore ionic conductances were measured before and after voltage application in order to test for changes in pore diameter due to electrochemical oxidation or reduction. TEM imaging was used to confirm these observations. While non-passivated pores were electrochemically oxidized, neither electrochemical oxidation nor reduction was observed for passivated pores. Bubble formation through water decomposition could be detected in non-passivated pores in KCl/water solutions but was not observed in 90% glycerol solutions. The use of a protective self-assembled monolayer of hexadecylphosphonic acid (HDPA) was also investigated.

  5. Nanoscale magnetism and novel electronic properties of a bilayer bismuth(111) film with vacancies and chemical doping.

    Science.gov (United States)

    Sahoo, M P K; Zhang, Yajun; Wang, Jie

    2016-07-27

    Magnetically doped topological insulators (TIs) exhibit several exotic phenomena including the magnetoelectric effect and quantum anomalous Hall effect. However, from an experimental perspective, incorporation of spin moment into 3D TIs is still challenging. Thus, instead of 3D TIs, the 2D form of TIs may open up new opportunities to induce magnetism. Based on first principles calculations, we demonstrate a novel strategy to realize robust magnetism and exotic electronic properties in a 2D TI [bilayer Bi(111) film: abbreviated as Bi(111)]. We examine the magnetic and electronic properties of Bi(111) with defects such as bismuth monovacancies (MVs) and divacancies (DVs), and these defects decorated with 3d transition metals (TMs). It has been observed that the MV in Bi(111) can induce novel half metallicity with a net magnetic moment of 1 μB. The origin of half metallicity and magnetism in MV/Bi(111) is further explained by the passivation of the σ-dangling bonds near the defect site. Furthermore, in spite of the nonmagnetic nature of DVs, the TMs (V, Cr, Mn, and Fe) trapped at the 5/8/5 defect structure of DVs can not only yield a much higher spin moment than those trapped at the MVs but also display intriguing electronic properties such as metallic, semiconducting and spin gapless semiconducting properties. The predicted magnetic and electronic properties of TM/DV/Bi(111) systems are explained through density of states, spin density distribution and Bader charge analysis. PMID:27406933

  6. Nanoscale magnetism and novel electronic properties of a bilayer bismuth(111) film with vacancies and chemical doping.

    Science.gov (United States)

    Sahoo, M P K; Zhang, Yajun; Wang, Jie

    2016-07-27

    Magnetically doped topological insulators (TIs) exhibit several exotic phenomena including the magnetoelectric effect and quantum anomalous Hall effect. However, from an experimental perspective, incorporation of spin moment into 3D TIs is still challenging. Thus, instead of 3D TIs, the 2D form of TIs may open up new opportunities to induce magnetism. Based on first principles calculations, we demonstrate a novel strategy to realize robust magnetism and exotic electronic properties in a 2D TI [bilayer Bi(111) film: abbreviated as Bi(111)]. We examine the magnetic and electronic properties of Bi(111) with defects such as bismuth monovacancies (MVs) and divacancies (DVs), and these defects decorated with 3d transition metals (TMs). It has been observed that the MV in Bi(111) can induce novel half metallicity with a net magnetic moment of 1 μB. The origin of half metallicity and magnetism in MV/Bi(111) is further explained by the passivation of the σ-dangling bonds near the defect site. Furthermore, in spite of the nonmagnetic nature of DVs, the TMs (V, Cr, Mn, and Fe) trapped at the 5/8/5 defect structure of DVs can not only yield a much higher spin moment than those trapped at the MVs but also display intriguing electronic properties such as metallic, semiconducting and spin gapless semiconducting properties. The predicted magnetic and electronic properties of TM/DV/Bi(111) systems are explained through density of states, spin density distribution and Bader charge analysis.

  7. Efficient water-splitting device based on a bismuth vanadate photoanode and thin-film silicon solar cells.

    Science.gov (United States)

    Han, Lihao; Abdi, Fatwa F; van de Krol, Roel; Liu, Rui; Huang, Zhuangqun; Lewerenz, Hans-Joachim; Dam, Bernard; Zeman, Miro; Smets, Arno H M

    2014-10-01

    A hybrid photovoltaic/photoelectrochemical (PV/PEC) water-splitting device with a benchmark solar-to-hydrogen conversion efficiency of 5.2% under simulated air mass (AM) 1.5 illumination is reported. This cell consists of a gradient-doped tungsten-bismuth vanadate (W:BiVO4 ) photoanode and a thin-film silicon solar cell. The improvement with respect to an earlier cell that also used gradient-doped W:BiVO4 has been achieved by simultaneously introducing a textured substrate to enhance light trapping in the BiVO4 photoanode and further optimization of the W gradient doping profile in the photoanode. Various PV cells have been studied in combination with this BiVO4 photoanode, such as an amorphous silicon (a-Si:H) single junction, an a-Si:H/a-Si:H double junction, and an a-Si:H/nanocrystalline silicon (nc-Si:H) micromorph junction. The highest conversion efficiency, which is also the record efficiency for metal oxide based water-splitting devices, is reached for a tandem system consisting of the optimized W:BiVO4 photoanode and the micromorph (a-Si:H/nc-Si:H) cell. This record efficiency is attributed to the increased performance of the BiVO4 photoanode, which is the limiting factor in this hybrid PEC/PV device, as well as better spectral matching between BiVO4 and the nc-Si:H cell. PMID:25138735

  8. Optical and structural properties of indium doped bismuth selenide thin films

    Science.gov (United States)

    Pavagadhi, Himanshu; Vyas, S. M.; Patel, Piyush; Patel, Vimal; Patel, Jaydev; Jani, M. P.

    2015-08-01

    In: Bi2Se3 crystals were grown by Bridgman method at a growth velocity of 0.5cm/h with temperature gradient of 650 C/cm in our laboratory. The thin films of In:Bi2se3 were grown on amorphous substrate (glass) at a room temperature under a pressure of 10-4Pa by thermal evaporation technique. Thin film were deposited at various thicknesses and optical absorption spectrum of such thin films, obtain in wave no. range 300 to 2600 cm-1. The optical energy gap calculated from this data were found to be inverse function of square of thickness, particularly for thickness about 1800 Å or less. This dependence is explained in terms of quantum size effect. For thicker films, the bandgap is found to be independent of film thickness. For the surface stud of the as grown thin film by using AFM, which shows continuous film with some step height and surface roughness found in terms of few nm and particle size varies with respect to thickness.

  9. Resistivity and Seebeck coefficient measurements of a bismuth microwire array

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Y. [Graduate School of Science and Engineering, Saitama University, 338-8570 (Japan)]. E-mail: ishikawa@kan.env.gse.saitama-u.ac.jp; Hasegawa, Y. [Graduate School of Science and Engineering, Saitama University, 338-8570 (Japan); Morita, H. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Kurokouchi, A. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Wada, K. [Saitama Industrial Technology Center, Saitama Prefecture, 333-0844 (Japan); Komine, T. [Department of Media and Telecommunications Engineering, Ibaraki University, 316-8511 (Japan); Nakamura, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5252 (Japan)

    2005-11-01

    The resistivity and Seebeck coefficient of a bismuth microwire array (wire diameter: 25 {mu}m) were successfully measured from 25 to 300 K. To eliminate the influence of the contact resistance between the wire edges of the microwire array and copper electrodes, the titanium (100 nm)/copper (500 nm) film layers were deposited as interlayer on the wire edge by ion plating method. Copper electrodes were glued by using Pb-Sn solder. The resistivity and the Seebeck coefficient at 300 K were approximately 1.8x10{sup -6} {omega}m and -54x10{sup -6} V/K, respectively. The value of the resistivity and the Seebeck coefficient were in good agreement with those of bulk polycrystalline bismuth reported previously. Thus, the effects of the contact resistance for the microwire array were almost resolved, and the chemical reaction of the Pb-Sn solder and bismuth was prevented by using the thin-film layer. The technique is expected to be applicable to nanowire arrays as well.

  10. Nonlinear optical properties of zinc oxide doped bismuth thin films using Z-scan technique

    Science.gov (United States)

    Abed, S.; Bouchouit, K.; Aida, M. S.; Taboukhat, S.; Sofiani, Z.; Kulyk, B.; Figa, V.

    2016-06-01

    ZnO doped Bi thin films were grown on glass substrates by spray ultrasonic technique. This paper presents the effect of Bi doping concentration on structural and nonlinear optical properties of zinc oxide thin films. These thin films were characterized by X-ray diffractometer technique. XRD analysis revealed that the ZnO:Bi thin films indicated good preferential orientation along c-axis perpendicular to the substrate. The nonlinear optical properties such as nonlinear absorption coefficient (β) and third order nonlinear susceptibility (Imχ(3)) are investigated. The calculations have been performed with a Z scan technique using Nd:YAG laser emitting 532 nm. The reverse saturable absorption (RSA) mechanism was responsible for the optical limiting effect. The results suggest that this material considered as a promising candidate for future optical device applications.

  11. Critical film thickness for fracture in thin-film electrodes on substrates in the presence of interfacial sliding

    International Nuclear Information System (INIS)

    It is well known that thin-film electrodes on substrates could fracture during lithium insertion/extraction above a critical film thickness. Recent studies have revealed that lithium could facilitate sliding at the interface between lithiated Si and the underlying substrate. In this paper, we investigate fracture in thin-film electrodes and derive the critical film thickness for fracture as a function of both the fracture toughness of the film and the sliding resistance of the interface. The analysis indicates that a slippery interface due to lithiation could significantly decrease the critical thickness for fracture. (paper)

  12. Charge transport in films of Geobacter sulfurreducens on graphite electrodes as a function of film thickness

    KAUST Repository

    Jana, Partha Sarathi

    2014-01-01

    Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis. This journal is © the Partner Organisations 2014.

  13. A glucose biosensor using methyl viologen redox mediator on carbon film electrodes

    OpenAIRE

    Ghica, Mariana Emilia; Christopher M. A. Brett

    2005-01-01

    A new methyl viologen-mediated amperometric enzyme electrode sensitive to glucose has been developed using carbon film electrode substrates. Carbon film electrodes from resistors fabricated by pyrolytic deposition of carbon were modified by immobilization of glucose oxidase through cross-linking with glutaraldehyde in the presence of bovine serum albumin. The mediator, methyl viologen, was directly immobilised with the enzyme together with Nafion cation-exchange polymer. The electrochemistry ...

  14. An experimental analysis of thick-film solid-state reference electrodes

    OpenAIRE

    Sophocleous, Marios; Glanc-Gostkiewicz, Monika; Atkinson, John Karl; Garcia-Breijo, Eduardo

    2012-01-01

    Thick-Film planar solid-state Silver/Silver Chloride (Ag/AgCl) reference electrodes were developed and tested for ion susceptibility and long term drift in approximately 0.04 M potassium chloride (KCl) solution. Various types of electrodes were tested exhibiting stabilities down to 2 millivolts per decade change of chloride concentration. It is demonstrated that Thick-Film reference electrodes are suitable for use in underground soil measurements due to their ruggedness and robustness.

  15. Comparison of lanthanum substituted bismuth titanate (BLT) thin films deposited by sputtering and pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Besland, M.P. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France)]. E-mail: Marie-Paule.Besland@cnrs-imn.fr; Djani-ait Aissa, H. [Division milieux Ionises et lasers, Centre de Developpement des Technologies Avancees CDTA, Baba Hassen Alger, Algerie (Algeria); Barroy, P.R.J. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France); Lafane, S. [Division milieux Ionises et lasers, Centre de Developpement des Technologies Avancees CDTA, Baba Hassen Alger, Algerie (Algeria); Tessier, P.Y. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France); Angleraud, B. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France); Richard-Plouet, M. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France); Brohan, L. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France); Djouadi, M.A. [Institut des Materiaux Jean Rouxel, Universite de Nantes, UMR CNRS 6502, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes cedex 3 (France)

    2006-01-20

    Bi{sub 4-x}La {sub x}Ti{sub 3}O{sub 12} (BLT {sub x}) (x = 0 to 1) thin films were grown on silicon (100) and platinized substrates Pt/TiO{sub 2}/SiO{sub 2}/Si using RF diode sputtering, magnetron sputtering and pulsed laser deposition (PLD). Stoichiometric home-synthesized targets were used. Reactive sputtering was investigated in argon/oxygen gas mixture, with a pressure ranging from 0.33 to 10 Pa without heating the substrate. PLD was investigated in pure oxygen, at a chamber pressure of 20 Pa for a substrate temperature of 400-440 deg. C. Comparative structural, chemical, optical and morphological characterizations of BLT thin films have been performed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Photoelectron Spectroscopy (XPS), Spectro-ellipsometric measurements (SE) and Atomic Force Microscopy (AFM). Both sputtering techniques allow to obtain uniform films with thickness ranging from 200 to 1000 nm and chemical composition varying from (Bi,La){sub 2} Ti{sub 3} O{sub 12} to (Bi,La){sub 4.5}Ti{sub 3}O{sub 12}, depending on deposition pressure and RF power. In addition, BLT films deposited by magnetron sputtering, at a pressure deposition ranging from 1.1 to 5 Pa, were well-crystallized after a post-deposition annealing at 650 deg. C in oxygen. They exhibit a refractive index and optical band gap of 2.7 and 3.15 eV, respectively. Regarding PLD, single phase and well-crystallized, 100-200 nm thick BLT films with a stoichiometric (Bi,La){sub 4}Ti{sub 3}O{sub 12} chemical composition were obtained, exhibiting in addition a preferential orientation along (200). It is worth noting that BLT films deposited by magnetron sputtering are as well-crystallized than PLD ones.

  16. Comparison of lanthanum substituted bismuth titanate (BLT) thin films deposited by sputtering and pulsed laser deposition

    International Nuclear Information System (INIS)

    Bi4-xLa xTi3O12 (BLT x) (x = 0 to 1) thin films were grown on silicon (100) and platinized substrates Pt/TiO2/SiO2/Si using RF diode sputtering, magnetron sputtering and pulsed laser deposition (PLD). Stoichiometric home-synthesized targets were used. Reactive sputtering was investigated in argon/oxygen gas mixture, with a pressure ranging from 0.33 to 10 Pa without heating the substrate. PLD was investigated in pure oxygen, at a chamber pressure of 20 Pa for a substrate temperature of 400-440 deg. C. Comparative structural, chemical, optical and morphological characterizations of BLT thin films have been performed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Photoelectron Spectroscopy (XPS), Spectro-ellipsometric measurements (SE) and Atomic Force Microscopy (AFM). Both sputtering techniques allow to obtain uniform films with thickness ranging from 200 to 1000 nm and chemical composition varying from (Bi,La)2 Ti3 O12 to (Bi,La)4.5Ti3O12, depending on deposition pressure and RF power. In addition, BLT films deposited by magnetron sputtering, at a pressure deposition ranging from 1.1 to 5 Pa, were well-crystallized after a post-deposition annealing at 650 deg. C in oxygen. They exhibit a refractive index and optical band gap of 2.7 and 3.15 eV, respectively. Regarding PLD, single phase and well-crystallized, 100-200 nm thick BLT films with a stoichiometric (Bi,La)4Ti3O12 chemical composition were obtained, exhibiting in addition a preferential orientation along (200). It is worth noting that BLT films deposited by magnetron sputtering are as well-crystallized than PLD ones

  17. Distributed Phase Shifter with PyrochloreBismuth Zinc Niobate Thin Films

    OpenAIRE

    Park, Jaehoon; Lu, Jiwei; Boesch, Damien; Stemmer, Susanne; York, Robert A.

    2006-01-01

    A monolithic Ku-band phase shifter employing voltage tunable Bi1 5Zn1 0Nb1 5O7 (BZN) thin film parallel plate capacitors is reported. BZN films were deposited by radio frequency magnetron sputtering on single-crystal sapphire substrates. A nine-section distributed coplanar waveguide loaded-line phase-shifter structure was designed. A differential phase shift of 175 was achieved with a maximum insertion loss of 3.5 dB at 15 GHz, giving a figure of merit 50 dB. To the best of our knowledge, thi...

  18. Digital simulation of anodic stripping voltammetry from thin film electrodes

    International Nuclear Information System (INIS)

    The anodic stripping voltammetry (ASV) is routinely applied to control of Cu(II) in heavy water in the primary cooling loop of the Nuclear Power Reactor. The anodic stripping voltammetry (ASV) is a very well-known technique in electroanalytical chemistry. However, due to the complexity of the phenomena, it is practised with the fundamentals of empiric considerations. A geometric model for the anodic stripping voltammetry (ASV) from thin film electrodes which can be calculated by explicit digital simulation method is proposed as a possibility of solving the electrochemically reversible, cuasi-reversible and irreversible reactions under linear potential scan and multiple potential scans. (Until now the analytical mathematical method was applied to reversible reactions). All the results are compared with analytical solutions and experimental results and it permits to conclude that the anodic stripping voltammetry (ASV) can be studied with the simplicity and potentialities of explicit digital simulation methods. (M.E.L.)

  19. Low-Power Super-resolution Readout with Antimony Bismuth Alloy Film as Mask layer

    Institute of Scientific and Technical Information of China (English)

    JIANG Lai-Xin; WU Yi-Qun; WANG Yang; WEI Jing-Song; GAN Fu-Xi

    2009-01-01

    Sb-Bi alloy films are proposed as a new kind of super-resolution mask layer with low readout threshold power. Using the Sb-Bi alloy film as a mask layer and SiN as a protective layer in a read-only memory disc, the super-resolution pits with diameters of 38Onm are read out by a dynamic setup, the laser wavelength is 78Onto and the numerical aperture of pickup lens is 0.45. The effects of the Sb-Bi thin film thickness, laser readout power and disc rotating velocity on the readout signal are investigated. The results show that the threshold laser power of super-resolution readout of the Sb-Bi mask layer is about 0.5roW, and the corresponding carrier-to-noise ratio is about 20dB at the film thickness of 5Ohm. The super-resolution mechanism of the Sb-Bi alloy mask layer is discussed based on its temperature dependence of reflection.

  20. On the doping problem of CdTe films: The bismuth case

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Brown, M. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Ruiz, C.M. [Depto. Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Vidal-Borbolla, M.A. [Instituto de Investigacion en Comunicacion Optica, Av. Karakorum 1470, Lomas 4a. Secc., 78210 San Luis Potosi, SLP (Mexico); Ramirez-Bon, R. [CINVESTAV-IPN, U. Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Santiago de Queretaro, Qro. (Mexico); Sanchez-Meza, E. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Tufino-Velazquez, M. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)], E-mail: mtufinovel@yahoo.com.mx; Calixto, M. Estela [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Compaan, A.D. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Contreras-Puente, G. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)

    2008-08-30

    The controlled increase of hole concentration is an important issue and still an unsolved problem for polycrystalline CdTe-based solar cells. The typical hole concentration of as-grown CdTe thin-films goes up to 10{sup 13} cm{sup -3}, depending on the specific growth technique. The highest electron concentration obtained for CdS, the suitable window partner material of CdTe, is around 10{sup 15} cm{sup -3}. Thus, the PV-performance of a CdS/CdTe device can be optimized if the hole concentration in CdTe is increased. We have faced up this problem by studying the electrical properties of two types of CdTe films: CdTe films grown by Close Space Vapor Transport using a CdTe:Bi powder as the starting material and CdTe sputtered films doped by implantation with different Bi-doses. Temperature-dependent resistivity and Hall effect measurements and a discussion on the efficiency of both doping processes are presented.

  1. On the doping problem of CdTe films: The bismuth case

    International Nuclear Information System (INIS)

    The controlled increase of hole concentration is an important issue and still an unsolved problem for polycrystalline CdTe-based solar cells. The typical hole concentration of as-grown CdTe thin-films goes up to 1013 cm-3, depending on the specific growth technique. The highest electron concentration obtained for CdS, the suitable window partner material of CdTe, is around 1015 cm-3. Thus, the PV-performance of a CdS/CdTe device can be optimized if the hole concentration in CdTe is increased. We have faced up this problem by studying the electrical properties of two types of CdTe films: CdTe films grown by Close Space Vapor Transport using a CdTe:Bi powder as the starting material and CdTe sputtered films doped by implantation with different Bi-doses. Temperature-dependent resistivity and Hall effect measurements and a discussion on the efficiency of both doping processes are presented

  2. Applications of Silver Nanowires on Transparent Conducting Film and Electrode of Electrochemical Capacitor

    Directory of Open Access Journals (Sweden)

    Yuan-Jun Song

    2014-01-01

    Full Text Available Silver nanowire has potential applications on transparent conducting film and electrode of electrochemical capacitor due to its excellent conductivity. Transparent conducting film (G-film was prepared by coating silver nanowires on glass substrate using Meyer rod method, which exhibited better performance than carbon nanotube and graphene. The conductivity of G-film can be improved by increasing sintering temperature. Electrode of electrochemical capacitor (I-film was fabricated through the same method with G-film on indium tin oxide (ITO. CV curves of I-film under different scanning rates had obvious redox peaks, which indicated that I-film exhibited excellent electrochemical pseudocapacitance performance and good reversibility during charge/discharge process. In addition, the specific capacitance of I-film was measured by galvanostatic charge/discharge experiments, indicating that I-film exhibits high special capacitance and excellent electrochemical stability.

  3. Novel p-Type Conductive Semiconductor Nanocrystalline Film as the Back Electrode for High-Performance Thin Film Solar Cells.

    Science.gov (United States)

    Zhang, Ming-Jian; Lin, Qinxian; Yang, Xiaoyang; Mei, Zongwei; Liang, Jun; Lin, Yuan; Pan, Feng

    2016-02-10

    Thin film solar cells, due to the low cost, high efficiency, long-term stability, and consumer applications, have been widely applied for harvesting green energy. All of these thin film solar cells generally adopt various metal thin films as the back electrode, like Mo, Au, Ni, Ag, Al, graphite, and so forth. When they contact with p-type layer, it always produces a Schottky contact with a high contact potential barrier, which greatly affects the cell performance. In this work, we report for the first time to find an appropriate p-type conductive semiconductor film, digenite Cu9S5 nanocrystalline film, as the back electrode for CdTe solar cells as the model device. Its low sheet resistance (16.6 Ω/sq) could compare to that of the commercial TCO films (6-30 Ω/sq), like FTO, ITO, and AZO. Different from the traditonal metal back electrode, it produces a successive gradient-doping region by the controllable Cu diffusion, which greatly reduces the contact potential barrier. Remarkably, it achieved a comparable power conversion efficiency (PCE, 11.3%) with the traditional metal back electrode (Cu/Au thin films, 11.4%) in CdTe cells and a higher PCE (13.8%) with the help of the Au assistant film. We believe it could also act as the back electrode for other thin film solar cells (α-Si, CuInS2, CIGSe, CZTS, etc.), for their performance improvement. PMID:26736028

  4. Novel p-Type Conductive Semiconductor Nanocrystalline Film as the Back Electrode for High-Performance Thin Film Solar Cells.

    Science.gov (United States)

    Zhang, Ming-Jian; Lin, Qinxian; Yang, Xiaoyang; Mei, Zongwei; Liang, Jun; Lin, Yuan; Pan, Feng

    2016-02-10

    Thin film solar cells, due to the low cost, high efficiency, long-term stability, and consumer applications, have been widely applied for harvesting green energy. All of these thin film solar cells generally adopt various metal thin films as the back electrode, like Mo, Au, Ni, Ag, Al, graphite, and so forth. When they contact with p-type layer, it always produces a Schottky contact with a high contact potential barrier, which greatly affects the cell performance. In this work, we report for the first time to find an appropriate p-type conductive semiconductor film, digenite Cu9S5 nanocrystalline film, as the back electrode for CdTe solar cells as the model device. Its low sheet resistance (16.6 Ω/sq) could compare to that of the commercial TCO films (6-30 Ω/sq), like FTO, ITO, and AZO. Different from the traditonal metal back electrode, it produces a successive gradient-doping region by the controllable Cu diffusion, which greatly reduces the contact potential barrier. Remarkably, it achieved a comparable power conversion efficiency (PCE, 11.3%) with the traditional metal back electrode (Cu/Au thin films, 11.4%) in CdTe cells and a higher PCE (13.8%) with the help of the Au assistant film. We believe it could also act as the back electrode for other thin film solar cells (α-Si, CuInS2, CIGSe, CZTS, etc.), for their performance improvement.

  5. Magnetic, ferroelectric and leakage current properties of gadolinium doped bismuth ferrite thin films by sol–gel method

    International Nuclear Information System (INIS)

    Bi0.9Gd0.1FeO3 (BGFO) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by using the sol–gel technology. The effects of annealing temperature (400–700 °C) on microstructure and multiferroic properties of thin films were investigated. The X-ray diffraction analysis showed that the BGFO thin films had an orthorhombic structure. The thin films showed ferroelectric and ferromagnetic properties with remanent polarization (2Pr) of 10 μC/cm2, remnant magnetization (2Mr) of 2.4 emu/g and saturation magnetization (Ms) of 5.3 emu/g. A small leakage current density (J) was 4.64×10−8 A/cm2 under applied field 100 kV/cm. It was found that more than one conduction mechanism is involved in the electric field range used in these experiments. The leakage current mechanisms were controlled by Poole–Frenkel emission in the low electric field region and by Schottky emission from the Pt electrode in the high field region. - Highlights: • Bi3.96Pr0.04Ti2.95Nb0.05O12 thin films were prepared by sol–gel technology. • Thin films showed 2Pr of 10 μC/cm2, 2Mr of 2.4 emu/g and Ms of 5.3 emu/g. • Leakage current mechanisms were controlled by Poole–Frenkel and Schottky emission

  6. Photo-Corrosion of CdSe Film Electrode by Electrochemical Modulation Reflectance Spectrum

    Institute of Scientific and Technical Information of China (English)

    单忠强; 田建华; 刘义平; 田文娟

    2004-01-01

    The photo-corrosion of electrodeposited polycrystalline CdSe electrode was inhibited effectively by coating a thin layer of the conductive polyaniline (PAN) film. The relation between the performance and internal band structure of such film-covered PAN/CdSe electrode was studied by the electrochemical modulation reflectance spectrum (EMRS). EMRS of both CdSe and PAN/CdSe electrodes in K4Fe(CN)6/K3Fe(CN)6 solution exhibited typical France-Keidysh oscillations, by which the values of the energy gap and flat band potential were determined. The EMRS results indicated that the energy band structure of CdSe electrode was not changed after coated with PAN film, so that the photoelectrochemical characteristic of PAN/CdSe electrode was rather similar to that of CdSe electrode.

  7. Fabrication and electrochemical properties of free-standing single-walled carbon nanotube film electrodes

    Institute of Scientific and Technical Information of China (English)

    Niu Zhi-Qiang; Ma Wen-Jun; Dong Hai-Bo; Li Jin-Zhu; Zhou Wei-Ya

    2011-01-01

    An easily manipulative approach was presented to fabricate electrodes using free-standing single-walled carbon nanotube (SWCNT) films grown directly by chemical vapor deposition. Electrochemical properties of the electrodes were investigated. In comparison with the post-deposited SWCNT papers, the directly grown SWCNT film electrodes manifested enhanced electrochemical properties and sensitivity of sensors as well as excellent electrocatalytic activities. A transition from macroelectrode to nanoelectrode behaviours was observed with the increase of scan rate. The heat treatment of the SWCNT film electrodes increased the current signals of electrochemical analyser and background current, because the heat-treatment of the SWCNTs in air could create more oxide defects on the walls of the SWCNTs and make the surfaces of SWCNTs more hydrophilic. The excellent electrochemical properties of the directly grown and heat-treated free-standing SWCNT film electrodes show the potentials in biological and electrocatalytic applications.

  8. Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

    KAUST Repository

    Aktakka, Ethem Erkan

    2013-10-01

    This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm2-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μ W from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi2Te3 and Sb2Te3 thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers. © 2013 IEEE.

  9. Structural and electrical properties of samarium-substituted bismuth titanate ferroelectric thin films on Pt/TiO x/SiO2/Si substrates

    International Nuclear Information System (INIS)

    Polycrystalline samarium-substituted ferroelectric bismuth titanate films (Bi3.45Sm0.55Ti3O12) were prepared on Pt/TiO x/SiO2/Si substrates by chemical solution deposition (CSD) and were annealed at various temperatures. For comparison, films with similar composition were grown by pulsed laser deposition (PLD) and annealed at 700 deg. C. X-ray diffraction and Raman spectroscopy results showed similar crystallographic orientations and structures for the films fabricated using these different deposition methods. It was found that film crystallinity, structural, dielectric, ferroelectric and leakage current properties were strongly dependent upon the annealing temperature for CSD-derived films. Atomic force microscopy showed that film surface roughness values are comparable for both deposition methods following annealing at the same temperature, although PLD-grown films had a more uniform grain size. Cross-sectional images obtained by scanning electron microscopy revealed distinct grain shapes and structures: dense, columnar grains for PLD-grown films, spherical grains and a more porous structure for CSD-derived films. The remanent polarization of CSD-derived films increased with increasing annealing temperature. The PLD-grown films annealed at 700 deg. C showed higher remanent polarization (2P r = 41.8 μC/cm2) and lower coercive field (E c = 91 kV/cm), than CSD-derived films annealed at the same temperature (27.4 μC/cm2 and 121 kV/cm). The former also had a lower leakage current density (6.7 x 10-7 A/cm2) than the latter (4.6 x 10-6 A/cm2) at a dc electric field of 100 kV/cm (∼10 V), and both film types demonstrated fatigue-free behaviour up to 109 read/write switching cycles with 1 MHz bipolar pulses

  10. Fabrication of Thermoelectric Sensor and Cooling Devices Based on Elaborated Bismuth-Telluride Alloy Thin Films

    Directory of Open Access Journals (Sweden)

    Abdellah Boulouz

    2014-01-01

    Full Text Available The principal motivation of this work is the development and realization of smart cooling and sensors devices based on the elaborated and characterized semiconducting thermoelectric thin film materials. For the first time, the details design of our sensor and the principal results are published. Fabrication and characterization of Bi/Sb/Te (BST semiconducting thin films have been successfully investigated. The best values of Seebeck coefficient (α(T at room temperature for Bi2Te3, and (Bi1−xSbx2Te3 with x = 0.77 are found to be −220 µV/K and +240 µV/K, respectively. Fabrication and evaluation of performance devices are reported. 2.60°C of cooling of only one Peltier module device for an optimal current of Iopt=2.50 mA is obtained. The values of temperature measured by infrared camera, by simulation, and those measured by the integrated and external thermocouple are reported. A sensitivity of the sensors of 5 mV Torr−1 mW−1 for the pressure sensor has been found with a response time of about 600 ms.

  11. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode

    Institute of Scientific and Technical Information of China (English)

    Bin Zhou; Jiuhui Qu; Xu Zhao; Huijuan Liu

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating.After annealation at 400, 500, and 600℃, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry.The BiVO4 particles on the ITO glass surface had a monoclinic structure.The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV.In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichiorophenol and Bisphenol A degradation under visible light irradiation (λ.> 420 nm).Over 90% of the two organic pollutants were removed in 5 hr.A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  12. Electrochromic properties of WO3 thin film onto gold nanoparticles modified indium tin oxide electrodes

    International Nuclear Information System (INIS)

    Gold nanoparticles (GNPs) thin films, electrochemically deposited from hydrogen tetrachloroaurate onto transparent indium tin oxide (ITO) thin film coated glass, have different color prepared by variation of the deposition condition. The color of GNP film can vary from pale red to blue due to different particle size and their interaction. The characteristic of GNPs modified ITO electrodes was studied by UV-vis spectroscopy, scanning electron microscope (SEM) images and cyclic voltammetry. WO3 thin films were fabricated by sol-gel method onto the surface of GNPs modified electrode to form the WO3/GNPs composite films. The electrochromic properties of WO3/GNPs composite modified ITO electrode were investigated by UV-vis spectroscopy and cyclic voltammetry. It was found that the electrochromic performance of WO3/GNPs composite films was improved in comparison with a single component system of WO3.

  13. Optical and electrical properties of thin films of bismuth ferric oxide; Propiedades opticas y electricas de peliculas delgadas de oxido de bismuto ferrico

    Energy Technology Data Exchange (ETDEWEB)

    Cardona R, D.

    2014-07-01

    The bismuth ferric oxide (BFO) has caused great attention in recent years because of their multi ferric properties, making it very attractive for different technological applications. In this paper simultaneous ablation of two white (Bi and Fe{sub 2}O{sub 3}) was used in a reactive atmosphere (containing oxygen) to deposit thin films of BFO. The composition of the films is changed by controlling the plasma parameters such as the average kinetic energy of the ions (E p) and the plasma density (Np). The effects caused by excess of Bi and Fe in atomic structure and the optical and electrical properties of the films BiFeO{sub 3} in terms of plasma parameters were studied. The X-ray diffraction patterns of BFO samples with excess of bismuth above 2% at. They exhibited small changes in structure leading to improved levels of leakage currents compared to levels of the film with a stoichiometry close to BiFeO{sub 3} composition. These samples showed a secondary phase (Bi{sub 2}5FeO{sub 4}0 selenite type) that led to the increase in the values of band gap and resistivity as well as the improvement of the piezoelectric properties. On the other hand, the films with iron excess showed as secondary phase compounds of iron oxide (α - γ-Fe{sub 2}O{sub 3}) that caused increments in the conductivity and decrease in the values of band gap. The results are discussed in terms of the excesses of Bi and Fe which were correlated with the plasma parameters. (Author)

  14. Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials.

    Science.gov (United States)

    Stefik, Morgan

    2016-07-01

    The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO4 . A selective etching process was used with vanadium-rich depositions to enable the synthesis of phase-pure BiVO4 after spinodal decomposition. BiVO4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode using a hole-scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting. PMID:27246652

  15. Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials.

    Science.gov (United States)

    Stefik, Morgan

    2016-07-01

    The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO4 . A selective etching process was used with vanadium-rich depositions to enable the synthesis of phase-pure BiVO4 after spinodal decomposition. BiVO4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode using a hole-scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting.

  16. Measurement of secondary ionization coefficient of CaO film electrode

    Science.gov (United States)

    Suzuki, Susumu; Kashiwagi, Yasuhide; Itoh, Haruo

    2013-02-01

    The secondary ionization coefficient γ of a CaO film electrode is investigated taking into account the difference in breakdown voltage obtained by repeated voltage applications. Such measurement is performed under a sinusoidal voltage of 0.5 Hz. If the CaO film electrode acts as the cathode, breakdown voltage gradually decreases and converges to an almost constant value after several breakdowns. From the obtained results, the γ of the CaO film electrode is determined for each breakdown using Townsend's criterion. The γ in the first breakdown is lower than those in subsequent breakdowns, particularly in the steady state. The difference in γ is considered to originate from accumulated charges on the CaO film electrode. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  17. Thin film lithium-based batteries and electrochromic devices fabricated with nanocomposite electrode materials

    Science.gov (United States)

    Gillaspie, Dane T; Lee, Se-Hee; Tracy, C. Edwin; Pitts, John Roland

    2014-02-04

    Thin-film lithium-based batteries and electrochromic devices (10) are fabricated with positive electrodes (12) comprising a nanocomposite material composed of lithiated metal oxide nanoparticles (40) dispersed in a matrix composed of lithium tungsten oxide.

  18. Stable ultrathin partially oxidized copper film electrode for highly efficient flexible solar cells

    OpenAIRE

    ZHAO Guoqing; Wang, Wei; Bae, Tae-Sung; Lee, Sang-Geul; Mun, ChaeWon; Lee, Sunghun; Yu, Huashun; Lee, Gun-Hwan; Song, Myungkwan; Yun, Jungheum

    2015-01-01

    Advances in flexible optoelectronic devices have led to an increasing need for developing highly efficient, low-cost, flexible transparent conducting electrodes. Copper-based electrodes have been unattainable due to the relatively low optical transmission and poor oxidation resistance of copper. Here, we report the synthesis of a completely continuous, smooth copper ultra-thin film via limited copper oxidation with a trace amount of oxygen. The weakly oxidized copper thin film sandwiched betw...

  19. Systematic experimental study of pure shear type dielectric elastomer membranes with different electrode and film thicknesses

    Science.gov (United States)

    Hodgins, M.; Seelecke, S.

    2016-09-01

    An approach to reduce the voltage required for dielectric elastomer actuators is to reduce film thickness. However, if the electrode thickness is not similarly reduced, the electrode’s mechanical behavior can increasingly and negatively impact the overall actuator behavior. This effect is yet to be studied and quantified for pure shear type specimens; a type recommended in a recent DE standardization journal publication. Therefore, in this work, using pure shear specimens, a comparative study of membrane actuators of different film thickness (20, 50 and 100 μm) is performed. Electrodes of different thicknesses are screen printed and tested in a uniaxial test device. The stiffening effect due to the solid-state electrodes is demonstrated by performing force-elongation tests for specimens with and without electrodes. Additionally the importance of thin electrodes (relative to film thickness) was demonstrated through a number of electromechanical tests. Isotonic tests revealed a lower electro-mechanical sensitivity for the 20 μm film when compared with the 50 and 100 μm films. This was attributed to the relatively thick electrodes. Best actuation results were achieved when the total electrode thickness was at least 15x thinner than the dielectric membrane thickness.

  20. Micromachined dense palladium electrodes for thin-film solid acid fuel cells

    NARCIS (Netherlands)

    Unnikrishnan, Sandeep

    2009-01-01

    This thesis paves the way towards the microfabrication of a solid acid electrolyte based fuel cell (µSAFC), which has a membrane electrode assembly (MEA) consisting of a thin-film of water soluble electrolyte encapsulated between two dense palladium electrode membranes. This project work investigate

  1. Current distribution effects in AC impedance spectroscopy of electroceramic point contact and thin film model electrodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jacobsen, Torben

    2010-01-01

    The Finite-Element-Method (FEM) was used for the simulations of the effect of a changing current distribution during AC impedance spectrum recording on electroceramic point contact and thin film model electrodes. For pure electronic conducting point contact electrodes the transition from the prim...

  2. Process optimization for the sputter deposition of molybdenum thin films as electrode for AlN thin films

    International Nuclear Information System (INIS)

    Molybdenum thin films have been deposited on Ti/(100) Si substrates by dc sputtering. For process optimization, a design of experiments method was used with three input factors (target power, substrate temperature, and process gas flow). Deposition rate, resistivity, roughness, diffraction angle, and rocking curve width were analyzed as output responses using statistical analysis method. Subsequently, a process allowing the deposition of highly crystalline, smooth, and low resistivity Mo film was selected and tested against film thickness. The as-optimized sputtered molybdenum thin film was used as seeding electrode for the growth of highly c-axis textured AlN film by dc pulsed reactive sputtering

  3. Mg-Ni THIN FILM-A POTENTIAL NEGATIVE ELECTRODE FOR NIKEL-METAL HYDRIDE BATTERY

    Institute of Scientific and Technical Information of China (English)

    L.Z. Ouyang; C.Y. Chung; M.Q. Zeng; H. Wang; M. Zhu

    2003-01-01

    Mg-Ni thin films for nickel-metal hydride (Ni-MH) battery negative electrode were prepared on three different substrates by using magnetron sputtering with compacted Ni and Mg mixture powder. The microstructure of Mg-Ni thin films deposited on the glass and the Ni foil substrate respectively was studied by X-ray diffraction (XRD)and scanning electron microscopy (SEM). The results show that the Mg-Ni thin films were in amorphous structure and the composition of the thin film was homogeneous.Electrochemical measurement show the discharge capacity of the thin film negative electrode deposited on the foam Ni substrate was 234.8mAh/g in 6M alkaline electrolyte and the internal resistance was much lower than that of the electrode prepared by the ball-milled powder during the charge-discharge cycle.

  4. Multianalyte Biosensors for the Simultaneous Determination of Glucose and Galactose Based on Thin Film Electrodes

    Institute of Scientific and Technical Information of China (English)

    Neng Qin JIA; Zong Rang ZHANG; Jiang Zhong ZHU; Guo Xiong ZHANG

    2004-01-01

    A multianalyte biosensor for the simultaneous determination of glucose and galactose was developed by immobilizing glucose oxidase (GOD) and galactose oxidase (GAO) on Nafion-modified thin film platinum disk electrodes. The dual Pt working electrodes with disk shape and the surrounding ring shaped counter electrode were fabricated by thin film technology, which were integrated onto the same microchip. The response of the designed biosensor for glucose and galactose were linear up to 6.0 mmol/L and 3.5 mmol/L with sensitivities of 0.3 (A/mmol/L and 0.12 μA/mmol/L, respectively. No cross-talking effect was observed.

  5. Effect of Some Metal Ion Dopants on Electrochemical Properties of Ni(OH)2 Film Electrode

    Institute of Scientific and Technical Information of China (English)

    ZHANG Heng-bin; LIU Han-san; CAO Xue-jing; SUN Chia-chung

    2003-01-01

    The Ni(OH)2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition. The electrode reaction reversibility, the difficult extent of oxygen evolution, the proton diffusion coefficient, the discharge potential of middle value and the active material utilization of the Ni(OH)2 film electrode were compared with those of the ones doped with the metal ions by means of cyclic voltammetry, potential step and constant current charge-discharge experiments. It was found that Ca2+, Co2+, Cd2+, Al3+ etc. have obviously positive effect.

  6. Transparent nanoscale floating gate memory using self-assembled bismuth nanocrystals in Bi(2) Mg(2/3) Nb(4/3) O(7) (BMN) pyrochlore thin films grown at room temperature.

    Science.gov (United States)

    Jung, Hyun-June; Yoon, Soon-Gil; Hong, Soon-Ku; Lee, Jeong-Yong

    2012-07-01

    Bismuth nanocrystals for a nanoscale floating gate memory device are self-assembled in Bi(2) Mg(2/3) Nb(4/3) O(7) (BMN) dielectric films grown at room temperature by radio-frequency sputtering. The TEM cross-sectional image shows the "real" structure grown on a Si (001) substrate. The image magnified from the dotted box (red color) in the the cross-sectional image clearly shows bismuth nanoparticles at the interface between the Al(2) O(3) and HfO(2) layer (right image). Nanoparticles approximately 3 nm in size are regularly distributed at the interface.

  7. Studying the Performance of Conductive Polymer Films as Textile Electrodes for Electrical Bioimpedance Measurements

    International Nuclear Information System (INIS)

    With the goal of finding novel biocompatible materials suitable to replace silver in the manufacturing of textile electrodes for medical applications of electrical bioimpedance spectroscopy, three different polymeric materials have been investigated. Films have been prepared from different polymeric materials and custom bracelets have been confectioned with them. Tetrapolar total right side electrical bioimpedance spectroscopy (EBIS) measurements have been performed with polymer and with standard gel electrodes. The performance of the polymer films was compared against the performance of the gel electrodes. The results indicated that only the polypropylene 1380 could produce EBIS measurements but remarkably tainted with high frequency artefacts. The influence of the electrode mismatch, stray capacitances and large electrode polarization impedance are unclear and they need to be clarified with further studies. If sensorized garments could be made with such biocompatible polymeric materials the burden of considering textrodes class III devices could be avoided.

  8. Studying the Performance of Conductive Polymer Films as Textile Electrodes for Electrical Bioimpedance Measurements

    Science.gov (United States)

    Cunico, F. J.; Marquez, J. C.; Hilke, H.; Skrifvars, M.; Seoane, F.

    2013-04-01

    With the goal of finding novel biocompatible materials suitable to replace silver in the manufacturing of textile electrodes for medical applications of electrical bioimpedance spectroscopy, three different polymeric materials have been investigated. Films have been prepared from different polymeric materials and custom bracelets have been confectioned with them. Tetrapolar total right side electrical bioimpedance spectroscopy (EBIS) measurements have been performed with polymer and with standard gel electrodes. The performance of the polymer films was compared against the performance of the gel electrodes. The results indicated that only the polypropylene 1380 could produce EBIS measurements but remarkably tainted with high frequency artefacts. The influence of the electrode mismatch, stray capacitances and large electrode polarization impedance are unclear and they need to be clarified with further studies. If sensorized garments could be made with such biocompatible polymeric materials the burden of considering textrodes class III devices could be avoided.

  9. Diffusional transport to and through thin-layer nanoparticle film modified electrodes: capped CdSe nanoparticle modified electrodes.

    Science.gov (United States)

    Hepburn, William G; Batchelor-McAuley, Christopher; Tschulik, Kristina; Barnes, Edward O; Kachoosangi, Roohollah Torabi; Compton, Richard G

    2014-09-01

    We present a simple and general theoretical model which accounts fully for the influence of an electrode modifying non-electroactive layer on the voltammetric response of a diffusional redox probe. The layer is solely considered to alter the solubilities and diffusion coefficients of the electroactive species within the thin layer on the electrode surface. On this basis it is demonstrated how, first, the apparent electrochemical rate constant can deviate significantly from that measured at an unmodified electrode. Second, depending on the conditions within the layer the modification of the electrode may lead to either apparent 'negative' or 'positive' electrocatalytic effects without the true standard electrochemical rate constant for the electron transfer at the electrode surface being altered. Having presented the theoretical model three experimental cases are investigated, specifically, the reductions of ruthenium(III) hexaamine, oxygen and boric acid on a gold macro electrode with and without a multi-layer organic capped nanoparticle film. In the latter case of the reduction of boric acid the voltammetric reduction is found to be enhanced by the presence of the organic layer. This result is interpreted as being due to an increase in the solubility of the analyte within the non-electroactive layer and not due to an alteration of the standard electrochemical rate constant. PMID:25050481

  10. Investigation of Top/bottom Electrode and Diffusion Barrier Layer for PZT thick film MEMS Sensors

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Hindrichsen, Christian Carstensen; Lou-Møller, R.;

    2007-01-01

    In this work screen printed piezoelectric Ferroperm PZ26 lead zirconate titanate (PZT) thick film is used for two MEMS devices. A test structure is used to investigate several aspects regarding bottom and top electrodes. 450 nm ZrO2 thin film is found to be an insufficient diffusion barrier layer...... for thick film PZT sintered at 850degC. E-beam evaporated Al and Pt is patterned on PZT with a lift-off process with a line width down to 3 mum. The roughness of the PZT is found to have a strong influence on the conductance of the top electrode....

  11. Nanopatterned Metallic Films for Use As Transparent Conductive Electrodes in Optoelectronic Devices

    KAUST Repository

    Catrysse, Peter B.

    2010-08-11

    We investigate the use of nanopatterned metallic films as transparent conductive electrodes in optoelectronic devices. We find that the physics of nanopatterned electrodes, which are often optically thin metallic films, differs from that of optically thick metallic films. We analyze the optical properties when performing a geometrical transformation that maintains the electrical properties. For one-dimensional patterns of metallic wires, the analysis favors tall and narrow wires. Our design principles remain valid for oblique incidence and readily carry over to two-dimensional patterns. © 2010 American Chemical Society.

  12. Paper-supported nanostructured ultrathin gold film electrodes – Characterization and functionalization

    International Nuclear Information System (INIS)

    Highlights: • Mechanically stable ultrathin gold films can be prepared on a latex coated paper. • Thickness of ultrathin gold film determines its electrical and optical properties. • Surface properties of ultrathin gold films can be changed by thin film coatings. • Ultrathin gold film electrodes can be used in electrochemical experiments. - Abstract: Ultrathin gold films (UTGFs) were fabricated on a nanostructured latex-coated paper substrate by physical vapour deposition (PVD) with the aim to provide low-cost and flexible conductive electrodes in paper-based electronics. Morphological, electric and optical properties of UTGFs were dependent on the deposited film thickness. In addition, UTGFs were functionalized with insulating and hydrophobic 1-octadecanethiol self-assembled monolayer and inkjet-printed conductive and hydrophilic poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT–PSS) layer and their electrochemical properties were examined. Results showed that sufficient mechanical stability and adhesion of UTGFs deposited on latex-coated paper was achieved without the need on any additional adhesive layers, enabling a more robust fabrication process of the electrodes. UTGF electrodes tolerated extensive bending without adverse effects and conductivity comparable to the bulk gold was obtained already with the film thickness of 6 nm. Although not been fabricated with the high-throughput method like printing, a very low material consumption (∼12 μg/cm2) together with a high conductivity (resistivity < 3 × 10−6 Ω cm) makes the UTGFs electrodes potential candidates low-cost components in flexible electronics. In addition, the excellent stability of the UTGF electrodes in electrochemical experiments enables their application in the development of paper-based electrochemical platforms, e.g. for biosensing purposes

  13. Paper-supported nanostructured ultrathin gold film electrodes – Characterization and functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Ihalainen, Petri, E-mail: petri.ihalainen@abo.fi [Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku (Finland); Määttänen, Anni [Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku (Finland); Pesonen, Markus [Physics, Department of Natural Sciences, Åbo Akademi University, Turku (Finland); Sjöberg, Pia; Sarfraz, Jawad [Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku (Finland); Österbacka, Ronald [Physics, Department of Natural Sciences, Åbo Akademi University, Turku (Finland); Peltonen, Jouko [Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku (Finland)

    2015-02-28

    Highlights: • Mechanically stable ultrathin gold films can be prepared on a latex coated paper. • Thickness of ultrathin gold film determines its electrical and optical properties. • Surface properties of ultrathin gold films can be changed by thin film coatings. • Ultrathin gold film electrodes can be used in electrochemical experiments. - Abstract: Ultrathin gold films (UTGFs) were fabricated on a nanostructured latex-coated paper substrate by physical vapour deposition (PVD) with the aim to provide low-cost and flexible conductive electrodes in paper-based electronics. Morphological, electric and optical properties of UTGFs were dependent on the deposited film thickness. In addition, UTGFs were functionalized with insulating and hydrophobic 1-octadecanethiol self-assembled monolayer and inkjet-printed conductive and hydrophilic poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT–PSS) layer and their electrochemical properties were examined. Results showed that sufficient mechanical stability and adhesion of UTGFs deposited on latex-coated paper was achieved without the need on any additional adhesive layers, enabling a more robust fabrication process of the electrodes. UTGF electrodes tolerated extensive bending without adverse effects and conductivity comparable to the bulk gold was obtained already with the film thickness of 6 nm. Although not been fabricated with the high-throughput method like printing, a very low material consumption (∼12 μg/cm{sup 2}) together with a high conductivity (resistivity < 3 × 10{sup −6} Ω cm) makes the UTGFs electrodes potential candidates low-cost components in flexible electronics. In addition, the excellent stability of the UTGF electrodes in electrochemical experiments enables their application in the development of paper-based electrochemical platforms, e.g. for biosensing purposes.

  14. Influence of bismuth on properties and microstructures of Sr0.5Ba0.5–Bi TiO3 thin films

    Indian Academy of Sciences (India)

    Tao Wenhong; Wang Yin; Fu Xinghua; Wei Qihong

    2006-10-01

    The influence of bismuth (Bi) on the dielectric and ferroelectric properties of Sr0.5Ba0.5–Bi TiO3 (BST, 0 < < 0.030 mol) thin films was studied. The results showed that the dielectric constant (r) and dielectric loss (tan ) decreased, and temperature, m, for maximum and r (Curie temperature), moved to lower temperature with increasing Bi content. The r, s and c were 0.22 C/cm2, 0.32 C/cm2 and 60 kV/cm, respectively for Sr0.5Ba0.485Bi0.015TiO3 thin films measured at 100 Hz, 20 V. The microstructure of BST thin films was studied by XRD and TEM. Tetragonal perovskite grains existed in BST thin films, but the grain size decreased with increasing doping ratio in BST. The characteristic absorption band for octahedron [TiO2] (471.65 cm-1) was shifted to lower wave number.

  15. Electrode loading effect and high temperature performance of ZnO thin film ultrasonic transducers

    Science.gov (United States)

    Zhou, X. S.; Zhang, J.; Hou, R.; Zhao, C.; Kirk, K. J.; Hutson, D.; Hu, P. A.; Peng, S. M.; Zu, X. T.; Fu, Y. Q.

    2014-10-01

    Nanocrystalline ZnO films of 5.8 μm thick were sputter-deposited on ferritic carbon steel plates (25 × 25 × 3 mm3) and characterized for use as ultrasonic transducers at both room temperature and high temperatures. Electrode loading effects have been studied using two types of electrodes, i.e., sputtered Cr/Au (5/50 nm) and silver paste, with electrode diameters 0.7-2.5 mm. Longitudinal and transverse waves were obtained in pulse-echo tests using both types of electrodes. With a silver paste top electrode, a dominant longitudinal mode was obtained, but with a thin Cr/Au film as the top electrode, shear waves were more dominant. Pulse-echo tests of the ZnO transducers were also performed at elevated temperatures up to 450 °C using a carbon paste electrodes. The sputtered ZnO films maintained a stable crystalline structure and orientation at the elevated temperatures, and ZnO devices on ferritic carbon steel could be used successfully up to 400 °C. However, when the temperature was increased further, rapid surface oxidation of the ferritic carbon steel caused the failure of the transducer.

  16. Preparation of Bismuth Titanate Piezoelectric Ceramic Thick Film%钛酸铋压电陶瓷厚膜的制备

    Institute of Scientific and Technical Information of China (English)

    赵欣欣; 张帆

    2013-01-01

    Bismuth titanate (BIT) powders were prepared from bismuth nitrate, titanium tetrabutoxide and oxalic acid by the chemical coprecipitation method. Then BIT ceramic thick film was prepared by screen-printing method, and its crystal structure was characterized by XRD and SEM analysis, effect of calcination temperature on the orientation degree was also studied. The results show that BIT powders with single phase can be obtained by calcination at 650 oC for 2 h, nanoparticles whose particle size is smaller than1 µm can be obtained by ball milling;the grain orientation (00k) of BIT thick film prepared by sintering at 1 200 oC for 2 h with the heating rate of 10 oC/min is high, can reach to 95.5%.%  以五水硝酸铋草酸和钛酸四丁酯为原料,采用化学共沉淀法,制得钛酸铋(BIT)粉体。然后﹑采用多层晶粒生长法,通过丝网印刷制得BIT压电陶瓷厚膜。借助XRD和SEM对产物晶体结构进行表征,并研究烧结温度对取向度的影响。结果表明,650 oC煅烧2 h可获得单一晶相的BIT粉体,经球磨后得到粒径小于1μm纳米粉体。1200 oC,升温速率10 oC/min,保温2 h时烧结的BIT厚膜在(00k)方向上取向度最高,达到95.50%。

  17. 微波消解-铋膜/Nation修饰电极溶出伏安法测定鳗鱼中的镉含量%Determination of Cadmium in Eel by Microwave Digestion Followed by Stripping Voltammetry on Bismuth/Nation Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    李静; 李红波; 范大和; 王伟

    2011-01-01

    A stripping voltammetric method based on microwave digestion was developed for determining cadmium in eel on a bismuth/nafion modified electrode. Oxidation yield a well-defined square wave peak for Cd^2+ at about - 0.85 V. Nation concentration, bismuth film thickness, buffer solution pH, deposition potential accumulation time and other potential interference factors were investigated. A linear relationship was found between peak area and cadmium concentration over the range of 4.0 to 14.0 μg/L with a correlation coefficient of 0.9964. The limit of detection of the method was 0.2 μg/L. The sensor was highly sensitive and effective to detect cadmium even in the presence of several excess potential interference ions.%运用铋膜/Nation修饰电极耦合微波消解技术测定鳗鱼中的Cd^2+。Cd^2+在-0.85V处出现清晰的方波氧化峰。Nafion、铋膜的厚度、缓冲液的pH值、富集电位、富集时间及可能干扰物质的影响因素进行考察。Cd^2+在4.0~14.0μg/L质量浓度范围内线性关系,线性相关性系数为0.9964,检出限为0.2ug/L。结果表明,该传感器在过量的干扰离子存在条件下,表现出超灵敏性和有效性。

  18. Flexible electrochromic films based on CVD-graphene electrodes

    International Nuclear Information System (INIS)

    Graphene synthesized via chemical vapor deposition is a notable candidate for flexible large-area transparent electrodes due to its great physical properties and its 2D activated surface area. Electrochromic devices in optical displays, smart windows, etc are suitable applications for graphene when used as a transparent conductive electrode. In this study, various-layer graphene was synthesized via chemical vapor deposition, and inorganic WOx was deposited on the layers, which have advantageous columnar structures and W6+ and W4+ oxidation states. The characteristics of graphene and WOx were verified using optical transmittance, Raman spectroscopy, x-ray photoelectron spectroscopy and scanning electron microscopy. The optimum transparent conductive electrode condition for controlling graphene layers was investigated based on the optical density and cyclic voltammetry. Electrochromic devices were fabricated using a three-layer graphene electrode, which had the best optical density. The graphene in the flexible electrochromic device demonstrated a potential for replacing ITO in flexible electronics. (paper)

  19. Flexible electrochromic films based on CVD-graphene electrodes

    Science.gov (United States)

    Choi, Dong Soo; Han, Seung Ho; Kim, Hyeongkeun; Kang, So Hee; Kim, Yena; Yang, Cheol-Min; Kim, Tae Young; Yoon, Dae Ho; Yang, Woo Seok

    2014-09-01

    Graphene synthesized via chemical vapor deposition is a notable candidate for flexible large-area transparent electrodes due to its great physical properties and its 2D activated surface area. Electrochromic devices in optical displays, smart windows, etc are suitable applications for graphene when used as a transparent conductive electrode. In this study, various-layer graphene was synthesized via chemical vapor deposition, and inorganic WOx was deposited on the layers, which have advantageous columnar structures and W6+ and W4+ oxidation states. The characteristics of graphene and WOx were verified using optical transmittance, Raman spectroscopy, x-ray photoelectron spectroscopy and scanning electron microscopy. The optimum transparent conductive electrode condition for controlling graphene layers was investigated based on the optical density and cyclic voltammetry. Electrochromic devices were fabricated using a three-layer graphene electrode, which had the best optical density. The graphene in the flexible electrochromic device demonstrated a potential for replacing ITO in flexible electronics.

  20. Electrochemical Deposition and Properties of Nanometerstructure Ce-doped Lead Dioxide Film Electrode

    Institute of Scientific and Technical Information of China (English)

    艾仁云; 李嘉庆; 李洛平; 彭惠琦; 杨娅; 金利通

    2005-01-01

    The effect of Ce(Ⅲ) on the morphology and structure of deposited film of lead dioxide was studied by cyclic voltammetry (CV), X-ray diffractometry (XRD) and scanning tunneling microscopy (STM). The results indicated that the Ce-doped PbO2 film consisted of a mixture of α- and β-phase of PbO2. Ce doping changed the size of PbO2 crystal grains and made the crystallite size on the electrode surface in the nanometer range. Owing to the formation of nanometer-structured grains, the specific surface areas and activity sites of the electrode surface were increased, hence the catalytic activity of Ce-doped PbO2 electrode was evidently higher than that of undoped PbO2 electrode.

  1. Lanthanide doped ceria thin films as possible counter electrode materials in electrochromic devices

    CERN Document Server

    Hartridge, A

    2000-01-01

    suitability of these thin films as counter electrodes in electrochromic devices. The final chapter then turns to the electrochemical insertion of lithium into these materials using cyclic voltammetry. All films studied enabled the reversible insertion of lithium with varying potentials and charge capacities without the loss of transmission of light common to other potential counter electrode materials. Certain compositions however, comprising ceria doped with Dy, Y, Nd and Pr, allowed enough lithium insertion (charge capacity) to fulfil the requirements of counter electrode materials in electrochromic devices. These materials are therefore worthy of further study. Crystalline solid solutions of lanthanide doped ceria have long been known for their high ionic conductivity and as such have found applications as oxygen sensors and in solid oxide fuel cells. With advances in preparative techniques over the years, thin films of ceria doped with zirconia and titania have been studied and found to possess the necess...

  2. Polymer Photovoltaic Cell Using TiO2/G-PEDOT Nanocomplex Film as Electrode

    Directory of Open Access Journals (Sweden)

    F. X. Xie

    2008-01-01

    Full Text Available Using TiO2/G-PEDOT (PEDOT/PSS doped with glycerol nanocomplex film as a substitute for metal electrode in organic photovoltaic cell is described. Indium tin oxide (ITO worked as cathode and TiO2/G-PEDOT nanocomplex works as anode. The thickness of TiO2 layer in nanocomplex greatly affects the act of this nonmetallic electrode of the device. To enhance its performance, this inverted organic photovoltaic cell uses another TiO2 layer as electron selective layer contacted to ITO coated glass substrates. All films made by solution processing techniques are coated on the transparent substrate (glass with a conducting film ITO. The efficiency of this solar cell is compared with the conventional device using Al as electrode.

  3. Study on hydrogen evolution performance of the carbon supported PtRu alloy film electrodes

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The carbon supported PtRu alloy film electrodes having Pt about 0.10 mg/cm2 or even less were prepared by ion beam sputtering method (IBSM). It was valued on the hydrogen analyse performance, the temperature influence factor and the stability by electroanalysis hydrogen analyse method. It was found that the carbon supported PtRu alloy film electrodes had higher hydrogen evolution performance and stability, such as the hydrogen evolution exchange current density (j0) was increase as the temperature (T) rised, and it overrun 150 mA/cm2 as the trough voltage in about 0.68V, and it only had about 2.8% decline in 500 h electrolytic process. The results demonstrated that the carbon supported PtRu alloy film electrodes kept highly catalytic activity and stability, and it were successfully used in pilot plant for producing H2 on electrolysis of H2S.

  4. Investigation of top electrode for PZT thick films based MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Kristiansen, Paw T.;

    2010-01-01

    influence on the conductance of the top electrode influencing the optimal top electrode thickness. A 100 nm thick top electrode on the PZT thick film with a surface roughness of 273 nm has a 4.5 times higher resistance compared to a similar wire on a planar SiO2 surface which has a surface roughness of less......In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used...... to investigate the optimal thickness of the top electrode, the degradation of the piezoelectric properties of the PZT film in absence of a diffusion barrier layer and finally how to fabricate electrical interconnects down the edge of the PZT thick film. The roughness of the PZT is found to have a strong...

  5. Effect of top electrode material on radiation-induced degradation of ferroelectric thin film structures

    Science.gov (United States)

    Brewer, Steven J.; Deng, Carmen Z.; Callaway, Connor P.; Paul, McKinley K.; Fisher, Kenzie J.; Guerrier, Jonathon E.; Rudy, Ryan Q.; Polcawich, Ronald G.; Jones, Jacob L.; Glaser, Evan R.; Cress, Cory D.; Bassiri-Gharb, Nazanin

    2016-07-01

    The effects of gamma irradiation on the dielectric and piezoelectric responses of Pb[Zr0.52Ti0.48]O3 (PZT) thin film stacks were investigated for structures with conductive oxide (IrO2) and metallic (Pt) top electrodes. The samples showed, generally, degradation of various key dielectric, ferroelectric, and electromechanical responses when exposed to 2.5 Mrad (Si) 60Co gamma radiation. However, the low-field, relative dielectric permittivity, ɛr, remained largely unaffected by irradiation in samples with both types of electrodes. Samples with Pt top electrodes showed substantial degradation of the remanent polarization and overall piezoelectric response, as well as pinching of the polarization hysteresis curves and creation of multiple peaks in the permittivity-electric field curves post irradiation. The samples with oxide electrodes, however, were largely impervious to the same radiation dose, with less than 5% change in any of the functional characteristics. The results suggest a radiation-induced change in the defect population or defect energy in PZT with metallic top electrodes, which substantially affects motion of internal interfaces such as domain walls. Additionally, the differences observed for stacks with different electrode materials implicate the ferroelectric-electrode interface as either the predominant source of radiation-induced effects (Pt electrodes) or the site of healing for radiation-induced defects (IrO2 electrodes).

  6. Investigation of Top/Bottom electrode and Diffusion Barrier Layer for PZT Thick Film MEMS Sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Thomsen, Erik Vilain

    2008-01-01

    Top and bottom electrodes for screen printed piezoelectric lead zirconate titanate, Pb(ZrxTi1 - x)O3 (PZT) thick film are investigated with respect to future MEMS devices. Down to 100 nm thick E-beam evaporated Al and Pt films are patterned as top electrodes on the PZT using a lift-off process wi...... with a line width down to 3 μ m. A 700 nm thick ZrO2 layer as insolating diffusion barrier layer is found to be insufficient as barrier layer for PZT on a silicon substrate sintered at 850°C. EDX shows diffusion of Si into the PZT layer....

  7. Cu2Sb thin film electrodes prepared by pulsed laser deposition f or lithium batteries

    OpenAIRE

    Song, Seung-Wan; Reade, Ronald P.; Cairns, Elton J.; Vaughey, Jack T.; Thackeray, Michael M.; Striebel, Kathryn A.

    2003-01-01

    Thin films of Cu2Sb, prepared on stainless steel and copper substrates with a pulsed laser deposition technique at room temperature, have been evaluated as electrodes in lithium cells. The electrodes operate by a lithium insertion/copper extrusion reaction mechanism, the reversibility of which is superior when copper substrates are used, particularly when electrochemical cycling is restricted to the voltage range 0.65-1.4 V vs. Li/Li+. The superior performance of Cu2Sb films on copper is...

  8. Dual electrodes degradation of Amaranth using a thin-film photocatalytic reactor with dual slant-placed electrodes.

    Science.gov (United States)

    Xu, Yun L; Li, Jue X; Zhong, Deng J; Jia, Jin P

    2013-01-01

    A dual slant-placed electrodes thin-film photocatalytic (PC) reactor was proposed and successfully applied to degrade Amaranth. In this PC reactor, both the TiO2/Ti photoanode and the Cu cathode are slant-placed in the reaction chamber, and aqueous thin-film formed on the surface of both electrodes as wastewater flowed over them. The degradation efficiency was significantly improved as a result of additional degradation at the cathode. When the TiO2 photocatalyst was irradiated with UV light, photogenerated electrons were spontaneously transferred from the anode to the cathode, driven by the electric field self-generated between the TiO2/Ti anode and the Cu cathode, based on the principle of establishing a Schottky barrier. On the Cu cathode surface, the transferred photoelectrons either reacted with dissolved oxygen to form H2O2, which then oxidized the dye, resulting in indirect oxidation decolourization, or reacted with the dye, resulting in direct reduction decolourization. The colour removal efficiency of the cathode was about half that of the photoanode. These processes together with direct oxidation of the photogenerated holes on the photoanode gave dual electrode degradation of the dye, and the degradation efficiency was significantly improved.

  9. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Boccard Mathieu

    2014-07-01

    Full Text Available When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration or superstrate (in p-i-n configuration. We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but identical sheet resistance and identical light-scattering properties. In the infrared part of the spectrum, parasitic absorption in the front or back electrode is shown to have a similar effect on the current generation in the cell, which is confirmed by modeling. By combining highly transparent front and back ZnO electrodes and high-quality silicon layers, a micromorph device with a stabilized efficiency of 11.75% is obtained.

  10. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    Science.gov (United States)

    Boccard, Mathieu; Cuony, Peter; Hänni, Simon; Stuckelberger, Michael; Haug, Franz-Josef; Meillaud, Fanny; Despeisse, Matthieu; Ballif, Christophe

    2014-07-01

    When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration) or superstrate (in p-i-n configuration). We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but identical sheet resistance and identical light-scattering properties. In the infrared part of the spectrum, parasitic absorption in the front or back electrode is shown to have a similar effect on the current generation in the cell, which is confirmed by modeling. By combining highly transparent front and back ZnO electrodes and high-quality silicon layers, a micromorph device with a stabilized efficiency of 11.75% is obtained.

  11. The role of front and back electrodes in parasitic absorption in thin-film solar cells

    OpenAIRE

    Boccard Mathieu; Cuony Peter; Hänni Simon; Stuckelberger Michael; Haug Franz-Josef; Meillaud Fanny; Despeisse Matthieu; Ballif Christophe

    2014-01-01

    When it comes to parasitic absorption in thin-film silicon solar cells, most studies focus on one electrode only, most of the time the substrate (in n-i-p configuration) or superstrate (in p-i-n configuration). We investigate here simultaneously the influence of the absorption in both front and back electrodes on the current density of tandem micromorph solar cells in p-i-n configuration. We compare four possible combinations of front and back electrodes with two different doping levels, but ...

  12. Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

    Directory of Open Access Journals (Sweden)

    Olana Bikila Nagasa

    2015-01-01

    Full Text Available In this work the determination of ascorbic acid (AA at glassy carbon electrode (GCE modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III. The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 μM to 45 μM with detection limit of 0.123 μM. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

  13. Development of liquid film thickness measurement technique by high-density multipoint electrodes method

    International Nuclear Information System (INIS)

    High-density multipoint electrode method was developed to measure a liquid film thickness transient on a curved surface. The devised method allows us to measure spatial distribution of liquid film with its conductance between electrodes. The sensor was designed and fabricated as a multilayer print circuit board, where electrode pairs were distributed in reticular pattern with narrow interval. In order to measure a lot of electrode pairs at a high sampling rate, signal-processing method used by the wire mesh sensor measurement system was applied. An electrochemical impedance spectrometry concludes that the sampling rate of 1000 slices/s is feasible without signal distortion by electric double layer. The method was validated with two experimental campaigns: (1) a droplet impingement on a flat film and (2) a jet impingement on a rod-shape sensor surface. In the former experiment, a water droplet having 4 mm in diameter impinged onto the 1 mm thick film layer. A visual observation study with high-speed video camera shows after the liquid impingement, the water layer thinning process was clearly demonstrated with the sensor. For the latter experiment, the flexible circuit board was bended to form a cylindrical shape to measure water film on a simulated fuel rod in bundle geometry. A water jet having 3 mm in diameter impinged onto the rod-shape sensor surface. The process of wetting area enlargement on the rod surface was demonstrated in the same manner that the video-frames showed. (author)

  14. Investigation on the dielectric properties of (Ba, Sr)TiO3 thin films on hybrid electrodes

    International Nuclear Information System (INIS)

    Ba0.65Sr0.35TiO3 (BST) thin films were deposited on Pt/Ti/SiO2/Si, RuO2/SiO2/Si and RuO2/Pt/Ti/SiO2/Si substrates by radio frequency magnetron sputtering technique. The effects of these bottom electrodes on the microstructure and dielectric properties of the BST thin films were investigated by using X-ray diffraction (XRD), atomic force microscope (AFM), transmission electron microscopy (TEM) and electrical measurements. The BST thin films on RuO2/Pt hybrid bottom electrodes exhibit good crystalline and interfacial structure with a thinner transition layer. Dielectric measurement reveals that the films on RuO2/Pt hybrid electrodes have comparable dielectric constant and loss tangent with the films on Pt electrode, and the dielectric tunability of BST films on RuO2/Pt reaches 38.2%, which is higher than that of BST films on a single Pt or RuO2 electrode. The BST thin films on RuO2/Pt exhibit lower leakage current density by nearly two orders' of magnitude than that on RuO2 electrode. The higher tunability and lower leakage current of the films on RuO2/Pt hybrid bottom electrodes are mainly attributed to the RuO2 layer, which facilitates the nucleation and growth of BST films, and inhibits the interfacial diffusion between the BST films and bottom electrodes. The results show a potential for RuO2/Pt hybrid electrodes replacing Pt electrode in microelectronic device applications.

  15. PEDOT as a Flexible Organic Electrode for a Thin Film Acoustic Energy Harvester.

    Science.gov (United States)

    Kim, Younghoon; Na, Jongbeom; Park, Chihyun; Shin, Haijin; Kim, Eunkyoung

    2015-08-01

    An efficient thin film acoustic energy harvester was explored using flexible poly(3,4-ethylene dioxythiophene) (PEDOT) films as electrodes in an all-organic triboelectric generator (AO-TEG). A thin film AO-TEG structured as PEDOT/Kapton//PET/PEDOT was prepared by the solution casting polymerization(SCP) on the dielectric polymer films. As-prepared AO-TEG showed high flexibility and durability due to the strong adhesion between the electrodes and the dielectric polymer. The short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power density (Pw) reached 50 mA/m(2), 700 V, and 12.9 W/m(2) respectively. The output current density decreased with the increase in the electrode resistance (Re), but the energy loss in the organic electrodes was negligible. The AO-TEG could light up 180 LEDs instantaneously upon touching of the AO-TEG with a palm (∼120 N). With the flexible structure, the AO-TEG was worn as clothes and generated electricity to light LEDs upon regular human movement. Furthermore, the AO-TEG was applicable as a thin film acoustic energy harvester, which used music to generate electricity enough for powering of 5 LEDs. An AO-TEG with a PEDOT electrode (Re = 200 Ω) showed instantaneous peak-to-peak voltage generation of 11 V under a sound pressure level (SPL) of 90-100 dB. The harvested acoustic energy through the AO-TEG was 350 μJ from the 4 min playing of the same single song. This is the first demonstration of a flexible triboelectric generator (TEG) using an organic electrode for harvesting acoustic energy from ambient environment.

  16. PEDOT as a Flexible Organic Electrode for a Thin Film Acoustic Energy Harvester.

    Science.gov (United States)

    Kim, Younghoon; Na, Jongbeom; Park, Chihyun; Shin, Haijin; Kim, Eunkyoung

    2015-08-01

    An efficient thin film acoustic energy harvester was explored using flexible poly(3,4-ethylene dioxythiophene) (PEDOT) films as electrodes in an all-organic triboelectric generator (AO-TEG). A thin film AO-TEG structured as PEDOT/Kapton//PET/PEDOT was prepared by the solution casting polymerization(SCP) on the dielectric polymer films. As-prepared AO-TEG showed high flexibility and durability due to the strong adhesion between the electrodes and the dielectric polymer. The short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power density (Pw) reached 50 mA/m(2), 700 V, and 12.9 W/m(2) respectively. The output current density decreased with the increase in the electrode resistance (Re), but the energy loss in the organic electrodes was negligible. The AO-TEG could light up 180 LEDs instantaneously upon touching of the AO-TEG with a palm (∼120 N). With the flexible structure, the AO-TEG was worn as clothes and generated electricity to light LEDs upon regular human movement. Furthermore, the AO-TEG was applicable as a thin film acoustic energy harvester, which used music to generate electricity enough for powering of 5 LEDs. An AO-TEG with a PEDOT electrode (Re = 200 Ω) showed instantaneous peak-to-peak voltage generation of 11 V under a sound pressure level (SPL) of 90-100 dB. The harvested acoustic energy through the AO-TEG was 350 μJ from the 4 min playing of the same single song. This is the first demonstration of a flexible triboelectric generator (TEG) using an organic electrode for harvesting acoustic energy from ambient environment. PMID:26153798

  17. Flexible electrochromic films based on CVD-graphene electrodes.

    Science.gov (United States)

    Soo Choi, Dong; Ho Han, Seung; Kim, Hyeongkeun; Hee Kang, So; Kim, Yena; Yang, Cheol-Min; Kim, Tae Young; Ho Yoon, Dae; Seok Yang, Woo

    2014-10-01

    Graphene synthesized via chemical vapor deposition is a notable candidate for flexible large-area transparent electrodes due to its great physical properties and its 2D activated surface area. Electrochromic devices in optical displays, smart windows, etc are suitable applications for graphene when used as a transparent conductive electrode. In this study, various-layer graphene was synthesized via chemical vapor deposition, and inorganic WO(x) was deposited on the layers, which have advantageous columnar structures and W(6+) and W(4+) oxidation states. The characteristics of graphene and WO(x) were verified using optical transmittance, Raman spectroscopy, x-ray photoelectron spectroscopy and scanning electron microscopy. The optimum transparent conductive electrode condition for controlling graphene layers was investigated based on the optical density and cyclic voltammetry. Electrochromic devices were fabricated using a three-layer graphene electrode, which had the best optical density. The graphene in the flexible electrochromic device demonstrated a potential for replacing ITO in flexible electronics. PMID:25201016

  18. Reversible potentiometric oxygen sensors based on polymeric and metallic film electrodes.

    Science.gov (United States)

    Yim, H S; Meyerhoff, M E

    1992-09-01

    Various materials and sensor configurations that exhibit reversible potentiometric responses to the partial pressure of oxygen at room temperature in neutral pH solution are examined. In one arrangement, platinum electrodes are coated with plasticized poly(vinyl chloride) films doped with a cobalt(II) tetraethylene pentamine complex. For such sensors, potentiometric oxygen response is attributed to a mixed potential originating from the underlying platinum electrode surface as well as a change in redox potential of the Co(II)-tetren-doped film as the complex binds oxygen reversibly. The response due to the platinum surface is prolonged by the presence of the Co(II)-tetren/PVC film. Alternately, thin films of metallic copper, electrochemically deposited on platinum and/or sputtered or vapor deposited on a single crystal silicon substrate, may be used for reversible oxygen sensing. The long-term reversibility and potentiometric stability of such copper film-based sensors is enhanced (up to 1 month) by preventing the formation of cuprous oxide on the surfaces via the application of an external nonpolarizing cathodic current through the working electrode or by specifically using sputtered copper films that have [100] preferred crystal structures as determined by X-ray diffraction. The implications of these findings in relation to fabricating analytically useful potentiometric oxygen sensors are discussed. PMID:1416035

  19. Composition dependence of the ferroelectric properties of lanthanum-modified bismuth titanate thin films grown by using pulsed-laser deposition

    CERN Document Server

    Bu, S D; Park, B H; Noh, T W

    2000-01-01

    Lanthanum-modified bismuth titanate, Bi sub 4 sub - sub x La sub x Ti sub 3 O sub 1 sub 2 (BLT), thin films with a La concentration of 0.25<=x<=1.00 were grown on Pt/Ti/SiO sub 2 /Si substrates by using pulsed-laser deposition. The BLT films showed well-saturated polarization-electric field curves whose remnant polarizations were 16.1 mu C/cm sup 2 , 27.8 mu C/cm sup 2 , 19.6 mu C/cm sup 2 , and 2.7 mu C/cm sup 2 , respectively, for x=0.25, 0.05, 0.75, and 1.00. The fatigue characteristics became better with increasing x up to 0.75. The Au/BLT/Pt capacitor with a La concentration of 0.50 showed an interesting dependence of the remanent polarization on the number of repetitive read/write cycles. On the other hand, the capacitor with a La concentration of 0.75 showed fatigue-free characteristics.

  20. Increased bismuth concentration in MBE GaAs{sub 1−x}Bi{sub x} films by oscillating III/V flux ratio during growth

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Adam W., E-mail: awood4@wisc.edu; Babcock, Susan E. [Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States); Li, Jincheng; Brown, April S. [Electrical and Computer Engineering, Duke University, Durham, North Carolina 27707 (United States)

    2015-05-15

    The authors have examined bismuth concentration profiles in GaAs{sub 1−x}Bi{sub x} films grown by molecular beam epitaxy using high angle annular dark field imaging (Z-contrast imaging) in an aberration-corrected scanning transmission electron microscope in conjunction with x-ray diffraction. Samples were grown with a gradient in each of the component fluxes, and therefore, the III/V ratio across the substrate. Rotating the sample during growth exposed the growth surface to an oscillating III/V flux ratio. Sinusoidal [Bi] profiles resulted in the growth direction, the wavelength and number of which were consistent with the growth rate and the rate of substrate rotation. However, the magnitude of [Bi] in the observed fluctuations was greater than the maximum [Bi] achieved using the same Bi flux and Ga/As flux ratios in steady-state conditions on a stationary substrate, suggesting that varying the III/V flux ratio during growth promotes the incorporation of Bi in GaAs{sub 1−x}Bi{sub x} films. A proposed qualitative model for how this enhancement might occur hypothesizes a critical role for alternating growth and shrinkage of Ga-Bi predroplet clusters on the surface as the growing material is rotated through Ga-rich and As-rich flux compositions.

  1. Electrochemical Deposition of CdTe Semiconductor Thin Films for Solar Cell Application Using Two-Electrode and Three-Electrode Configurations: A Comparative Study

    Directory of Open Access Journals (Sweden)

    O. K. Echendu

    2016-01-01

    Full Text Available Thin films of CdTe semiconductor were electrochemically deposited using two-electrode and three-electrode configurations in potentiostatic mode for comparison. Cadmium sulphate and tellurium dioxide were used as cadmium and tellurium sources, respectively. The layers obtained using both configurations exhibit similar structural, optical, and electrical properties with no specific dependence on any particular electrode configuration used. These results indicate that electrochemical deposition (electrodeposition of CdTe and semiconductors in general can equally be carried out using two-electrode system as well as the conventional three-electrode system without compromising the essential qualities of the materials produced. The results also highlight the advantages of the two-electrode configuration in process simplification, cost reduction, and removal of a possible impurity source in the growth system, especially as the reference electrode ages.

  2. Conductive plastic film electrodes for Pulsed Electric Field (PEF) treatment : A proof of principle

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Boxtel, L.B.J. van; Hatt, V.; Wouters, P.C.; Coronel, P.; Ferreira, J.A.

    2010-01-01

    Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so th

  3. Impermeable flexible liquid barrier film for encapsulation of DSSC metal electrodes

    Science.gov (United States)

    Yang, Junghee; Min, Misook; Yoon, Yeoheung; Kim, Won Jung; Kim, Sol; Lee, Hyoyoung

    2016-06-01

    Encapsulation of electronic devices such as dye-sensitized solar cells (DSSCs) is prone to degradation under normal atmospheric conditions, even with hermetic barriers on the metal electrodes. Overcoming this problem is crucial to increasing DSSC lifetimes and making them commercially viable. Herein, we report a new impermeable flexible liquid barrier film using polyvinyl alcohol (PVA) and partially reduced graphene oxide (PrGO), which dramatically enhances the lifetime of Ag metal electrodes (typically used in DSSCs) immersed in a highly acidic iodolyte solution. The Ag metal electrode encapsulated by the PVA/PrGO film survived for over 500 hrs, superior to existing barriers of glass frits, epoxy resins and polymers. The PVA/PrGO film strongly adheres to the Ag metal surface, and the resulting PVA/PrGO/Ag electrode is stable even on a curved substrate, with a sheet resistance nearly independent of curvature. These results give new insight for the design of high-performance and solution-processable flexible liquid barrier films for a wide range of applications, in particular for the encapsulation of electronic devices with liquid electrolytes.

  4. Characterisation of hydrophobic carbon nanofiber-silica composite film electrodes for redox liquid immobilisation

    International Nuclear Information System (INIS)

    Carbon (50-150 nm diameter) nanofibers were embedded into easy to prepare thin films of a hydrophobic sol-gel material and cast onto tin-doped indium oxide substrate electrodes. They promote electron transport and allow efficient electrochemical reactions at solid|liquid and at liquid|liquid interfaces. In order to prevent aggregation of carbon nanofibers silica nanoparticles of 7 nm diameter were added into the sol-gel mixture as a 'surfactant' and homogeneous high surface area films were obtained. Scanning electron microscopy reveals the presence of carbon nanofibers at the electrode surface. The results of voltammetric experiments performed in redox probe-ferrocenedimethanol solution in aqueous electrolyte solution indicate that in the absence of organic phase, incomplete wetting within the hydrophobic film of carbon nanofibers can cause hemispherical diffusion regime typical for ultramicroelectrode like behaviour. The hydrophobic film electrode was modified with two types of redox liquids: pure tert-butylferrocene or dissolved in 2-nitrophenyloctylether as a water-insoluble solvent and immersed in aqueous electrolyte solution. With a nanomole deposit of pure redox liquid, stable voltammetric responses are obtained. The presence of carbon nanofibers embedded in the mesoporous matrix substantially increases the efficiency of the electrode process and stability under voltammetric conditions. Also well-defined response for diluted redox liquids is obtained. From measurements in a range of different aqueous electrolyte media a gradual transition from anion transfer dominated to cation transfer dominated processes is inferred depending on the hydrophilicity of the transferring anion or cation

  5. Scanning electrochemical microscope characterization of thin film combinatorial libraries for fuel cell electrode applications

    Science.gov (United States)

    Black, M.; Cooper, J.; McGinn, P.

    2005-01-01

    Pt-Ru combinatorial libraries of potential fuel cell anode catalysts are formed by sequential sputter deposition through masks onto Si wafers. Scanning electrochemical microscopy (SECM) is employed for characterization of electrocatalytic activity. Aspects of using a scanning electrochemical microscope for characterization of an array of thin film fuel cell electrode materials are discussed. It is shown that in applying SECM to library characterization, careful attention must be paid to thin film annealing, specimen topography and tip degradation in order to realize meaningful results. Results from a Pt-Ru thin film library reveal the most active members near the 50 Pt/50 Ru composition.

  6. The effect of different electrode structures on the dielectric properties of lanthanum-doped lead titanate ferroelectric thin films

    Institute of Scientific and Technical Information of China (English)

    LIU Hong; PU Zhaohui; ZHU Xiaohong; XIAO Dingquan; ZHU Jianguo

    2007-01-01

    Lanthanum-doped lead titanate[(Pb0.9,La0.1)TiO3,PLT10]ferroelectric thin films were grown on Si(100)and Pt/Ti/SiO2/Si(100)substrates by radio frequency(RF)magnetron sputtering.The crystalline properties of PLT10 films were studied by X-ray diffractometry(XRD).Photolithographic technique was applied to fabricate the interdigital electrodes on PLT10 thin films on Si(100)substrates.The dielectric properties of PLT10 thin films with different electrodes were measured.At room temperature and 1 kHz testing frequency,the dielectric constant of the PLT10 min film with interdigital electrodes is 386.ThC dielectric constant of the PLT10 thin film fabricated under the same technological conditions with parallel plate electrodes structure is 365,while the dielectric constant and loss of the PLT10 thin film with interdigital electrodes are decreased faster than those of the film with parallel plate electrodes with increasing frequency.This is because more influences of interface state are introduced due to the interdigital electrode configuration.

  7. Semicylindrical acoustic transducer from a dielectric elastomer film with compliant electrodes.

    Science.gov (United States)

    Sugimoto, Takehiro; Ono, Kazuho; Ando, Akio; Morita, Yuichi; Hosoda, Kosuke; Ishii, Daisaku

    2011-08-01

    A semicylindrical acoustic transducer was constructed using a dielectric elastomer film with compliant electrodes that is an electroactive polymer composed of a polyurethane elastomer base and polyethylene dioxythiophene/polystyrene sulfonate electrodes. The use of this dielectric elastomer is advantageous because polyurethane is a common material that keeps its shape without any rigid frame. Because the dielectric elastomer films are essentially incompressible, electric-field-induced thickness changes are usually translated into much larger changes of the film area and side length. Here it is proposed that this change in side length can be utilized for sound generation when the film is bent into a semicylindrical shape. Accordingly, a semicylindrical acoustic transducer was fabricated using a film of thickness of 300 μm and its acoustic characteristics were investigated. The transducer can be operated at low applied voltages by reducing the film thickness, as long as the film is thick enough to generate sufficient force to overcome sound radiation impedance. The second harmonic distortion of the transducer was also investigated as a function of the ratio of the direct current bias voltage to the alternating current audio signal amplitude. PMID:21877790

  8. Miniaturized, Planar Ion-selective Electrodes Fabricated by Means of Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Robert Koncki

    2006-04-01

    Full Text Available Various planar technologies are employed for developing solid-state sensorshaving low cost, small size and high reproducibility; thin- and thick-film technologies aremost suitable for such productions. Screen-printing is especially suitable due to itssimplicity, low-cost, high reproducibility and efficiency in large-scale production. Thistechnology enables the deposition of a thick layer and allows precise pattern control.Moreover, this is a highly economic technology, saving large amounts of the used inks. Inthe course of repetitions of the film-deposition procedure there is no waste of material dueto additivity of this thick-film technology. Finally, the thick films can be easily and quicklydeposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodesbased on ionophores as well as crystalline ion-selective materials dedicated forpotentiometric measurements are demonstrated. Analytical parameters of these sensors arecomparable with those reported for conventional potentiometric electrodes. All mentionedthick-film strip electrodes have been totally fabricated in only one, fully automated thick-film technology, without any additional manual, chemical or electrochemical steps. In allcases simple, inexpensive, commercially available materials, i.e. flexible, plastic substratesand easily cured polymer-based pastes were used.

  9. Electrocatalytic Oxidation of Dopamine by Ferrocene in Lipid Film Cast on a Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    WANG,Jian-Guo(王建国); WU,Zheng-Yan(吴正岩); TANG,Ji-Lin(唐纪琳); TENG,Ren-Rui(滕人瑞); WANG,Er-Kang(汪尔康)

    2002-01-01

    The ferrocene-lipid film electrode was successfully prepared by means of casting the solution of ferrocene and lipid in chloroform onto a glassy carbon (GC) electrode surface. Ferrocene saved in the biological membrane gave a couple of quasi-reversble peaks of cyclic voltammmogram. The electrode displays a preferential electrocatalytic oxidation of dopamine (DA).The effect of electrocatalytic oxidation of DA depends on the solution pH and the negative charge lipid is in favor of catalytic oxidation of DA. The charistic was employed for separating the electrochemical responses of DA and ascorbic acid (AA). The electrode was assessed for the voltammtric differentiation of DA and AA. The measurement of DA can be achieved with differential pulse voltammetry in the presence of high conentration of AA. The catalytic peak current was proportional to the concentration of DA in the range of 1 ×10- 4-3 × 10-3 mol/L.

  10. Microscopically crumpled indium-tin-oxide thin films as compliant electrodes with tunable transmittance

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Hui-Yng [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); School of Engineering, Nanyang Polytechnic, Singapore 569830 (Singapore); Shrestha, Milan; Lau, Gih-Keong, E-mail: mgklau@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-09-28

    Indium-tin-oxide (ITO) thin films are perceived to be stiff and brittle. This letter reports that crumpled ITO thin films on adhesive poly-acrylate dielectric elastomer can make compliant electrodes, sustaining compression of up to 25% × 25% equi-biaxial strain and unfolding. Its optical transmittance reduces with crumpling, but restored with unfolding. A dielectric elastomer actuator (DEA) using the 14.2% × 14.2% initially crumpled ITO thin-film electrodes is electrically activated to produce a 37% areal strain. Such electric unfolding turns the translucent DEA to be transparent, with transmittance increased from 39.14% to 52.08%. This transmittance tunability promises to make a low-cost smart privacy window.

  11. Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes

    Science.gov (United States)

    Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I.; Maruyama, Shigeo; Matsuo, Yutaka

    2016-08-01

    Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via ‘sandwich transfer’, and MoOx thermal doping via ‘bridge transfer’. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%).

  12. Electron beam induced modifications of bismuth sulphide (Bi2S3) thin films: Structural and optical properties

    International Nuclear Information System (INIS)

    Thin films of Bi2S3 prepared by electrodeposition method are subjected to electron beam irradiation for different doses from 0 to 100 kGy in steps of 20 kGy in air at room temperature. The changes in structural, surface morphological and optical properties that occurred before and after irradiation in Bi2S3 thin films are studied using X-ray diffraction, scanning electron microscopy and UV-vis spectroscopy. It is shown that electron irradiation can be used as a tool to decrease the crystallite size of the irradiated films from 418 to 285 A as the dose varies from 20 to 100 kGy. The decrease in crystallinity of the films leading to the band gap energy of the films get blue shifted from unirradiated films. These results are explained in the light of thermal spike model.

  13. Bismuth, Metronidazole, and Tetracycline

    Science.gov (United States)

    Helidac® (as a kit containing Bismuth Subsalicylate, Metronidazole, Tetracycline) ... Bismuth, metronidazole, and tetracycline is used along with other ulcer medications to treat duodenal ulcers. It is in a class of medications called ...

  14. Semiconducting properties of oxide films formed onto an Nb electrode in NaOH solutions

    Directory of Open Access Journals (Sweden)

    VLADIMIR D. JOVIC

    2008-03-01

    Full Text Available In this paper, the results of the potentiostatic formation of homogeneous and heterogeneous, nano-crystalline passive films of Nb2O5 onto an Nb electrode in NaOH solutions of different concentrations at potentials lower than 3.0 V vs. SCE are presented. The semiconducting properties of such films were investigated by EIS measurements. After fitting the EIS results by appropriate equivalent circuits, the space charge capacitance (Csc and space charge resistance (Rsc of these films were determined. The donor density (Nsc, flat band potential (Efb and thickness of the space charge layer (dsc for such oxide films were determined from the corresponding Mott–Schottky (M–S plots. It is shown that all oxide films were n-type semiconductors in a certain potential range.

  15. Surface modification of polytetrafluoroethylene film using single liquid electrode atmosphericpressure glow discharge

    Institute of Scientific and Technical Information of China (English)

    Zhou Lan; Lü Guo-Hua; Chen Wei; Pang Hua; Zhang Gu-Ling; Yang Si-Ze

    2011-01-01

    Polytetrafluoroethylene films are treated by room temperature helium atmospheric pressure plasma plumes, which are generated with a home-made single liquid electrode plasma device. After plasma treatment, the water contact angle of polytetrafluoroethylene film drops from 114° to 46° and the surface free energy increases from 22.0 mJ/m2 to 59.1 mJ/m2. The optical emission spectrum indicates that there are reactive species such as O2+, O and He in the plasma plume. After plasma treatment, a highly crosslinking structure is formed on the film surface and the oxygen element is incorporated into the film surface in the forms of -C-O-C-, -C=O, and -O-C=O groups. Over a period of 10 days, the contact angle of the treated film is recovered by only about 10°, which indicates that the plasma surface modification is stable with time.

  16. Nanoporous MnO{sub x} thin-film electrodes synthesized by electrochemical lithiation/delithiation for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Hui; Lai, Man On; Lu, Li [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore)

    2011-02-15

    Nanoporous MnO{sub x} thin-film electrodes are synthesized using a combination of pulsed laser deposition (PLD) and electrochemical lithiation/delithiation methods. A dense Mn{sub 3}O{sub 4} thin-film deposited by PLD can transform into a nanoporous MnO{sub x} thin-film after electrochemical lithiation/delithiation. A nanoporous MnO{sub x} thin-film electrode exhibits significantly improved supercapacitive performance compared with an as-deposited Mn{sub 3}O{sub 4} thin-film electrode. A MnO{sub x} thin-film finally transforms into a MnO{sub 2} thin-film through an electrochemical oxidation process during continuous cyclic voltammetry scanning. (author)

  17. Electroanalysis of tetracycline using nickel-implanted boron-doped diamond thin film electrode applied to flow injection system.

    Science.gov (United States)

    Treetepvijit, Surudee; Chuanuwatanakul, Suchada; Einaga, Yasuaki; Sato, Rika; Chailapakult, Orawon

    2005-05-01

    The electrochemical analysis of tetracycline was investigated using nickel-implanted boron-doped diamond thin film electrode by cyclic voltammetry and amperometry with a flow injection system. Cyclic voltammetry was used to study the electrochemical oxidation of tetracycline. Comparison experiments were carried out using as-deposited boron-doped diamond thin film electrode (BDD). Nickel-implanted boron-doped diamond thin film electrode (Ni-DIA) provided well-resolved oxidation irreversible cyclic voltammograms. The current signals were higher than those obtained using the as-deposited BDD electrode. Results using nickel-implanted boron-doped diamond thin film electrode in flow injection system coupled with amperometric detection are presented. The optimum potential for tetracycline was 1.55 V versus Ag/AgCl. The linear range of 1.0 to 100 microM and the detection limit of 10 nM were obtained. In addition, the application for drug formulation was also investigated.

  18. Two layer flow of thin leaky dielectric films between electrodes

    Science.gov (United States)

    Dubrovina, Elizaveta; Craster, Richard; Papageorgiou, Demetrios

    2014-11-01

    The flow of two viscous conducting fluids between two electrodes is investigated. The fluids are assumed to be leaky dielectrics and two nonlinear coupled evolution equations are derived for the moving interface and the interfacial charge. These are solved numerically for three different cases in which the magnitude of the ratios of electric conductivities and permittivities is varied. A linear stability analysis indicates that electrical forces destabilize the system. These predictions are confirmed by numerical results which show that increasing the ratios of conductivities and permittivities leads to traveling waves that grow in amplitude.

  19. Novel Bismuth Nanotubes

    Institute of Scientific and Technical Information of China (English)

    苏长荣; 李家明

    2002-01-01

    Theoretical investigations show that bismuth nanotubes are semiconductors for all diameters. For smalldiameter bismuth nanotubes, the band structures and bandgaps vary strongly with the strong hybridization effect. When the diameters are larger than 18 A, the bandgaps ofBi (n, n) and (n, 0) nanotubes approach 0.63 e V, corresponding to the bandgap of bismuth sheet at the Γ point. Thus, bismuth nanotubes are expected to be a potential semiconductor nanomaterial in future nanoelectronics.

  20. Effect of fractal silver electrodes on charge collection and light distribution in semiconducting organic polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Chamousis, RL; Chang, LL; Watterson, WJ; Montgomery, RD; Taylor, RP; Moule, AJ; Shaheen, SE; Ilan, B; van de Lagemaat, J; Osterloh, FE

    2014-08-21

    Living organisms use fractal structures to optimize material and energy transport across regions of differing size scales. Here we test the effect of fractal silver electrodes on light distribution and charge collection in organic semiconducting polymer films made of P3HT and PCBM. The semiconducting polymers were deposited onto electrochemically grown fractal silver structures (5000 nm x 500 nm; fractal dimension of 1.71) with PEDOT:PSS as hole-selective interlayer. The fractal silver electrodes appear black due to increased horizontal light scattering, which is shown to improve light absorption in the polymer. According to surface photovoltage spectroscopy, fractal silver electrodes outperform the flat electrodes when the BHJ film thickness is large (>400 nm, 0.4 V photovoltage). Photocurrents of up to 200 microamperes cm(-2) are generated from the bulk heterojunction (BHJ) photoelectrodes under 435 nm LED (10-20 mW cm(-2)) illumination in acetonitrile solution containing 0.005 M ferrocenium hexafluorophosphate as the electron acceptor. The low IPCE values (0.3-0.7%) are due to slow electron transfer to ferrocenium ion and due to shunting along the large metal-polymer interface. Overall, this work provides an initial assessment of the potential of fractal electrodes for organic photovoltaic cells.

  1. Nanocarbon-copper thin film as transparent electrode

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, R. A.; Zhu, H.; Preston, Colin; LeMieux, M.; Jaim, H. M. Iftekhar; Hu, L., E-mail: binghu@umd.edu; Salamanca-Riba, L. G., E-mail: riba@umd.edu [Materials Science and Engineering Department, University of Maryland, College Park, Maryland 20742 (United States); Mansour, A. [Carderock Division, Naval Surface Warfare Center, West Bethesda, Maryland 20817 (United States); Zavalij, P. Y. [Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States); Rabin, O. [Materials Science and Engineering Department, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2015-05-11

    Researchers seeking to enhance the properties of metals have long pursued incorporating carbon in the metallic host lattice in order to combine the strongly bonded electrons in the metal lattice that yield high ampacity and the free electrons available in carbon nanostructures that give rise to high conductivity. The incorporation of carbon nanostructures into the copper lattice has the potential to improve the current density of copper to meet the ever-increasing demands of nanoelectronic devices. We report on the structure and properties of carbon incorporated in concentrations up to 5 wt. % (∼22 at. %) into the crystal structure of copper. Carbon nanoparticles of 5 nm–200 nm in diameter in an interconnecting carbon matrix are formed within the bulk Cu samples. The carbon does not phase separate after subsequent melting and re-solidification despite the absence of a predicted solid solution at such concentrations in the C-Cu binary phase diagram. This material, so-called, Cu covetic, makes deposition of Cu films containing carbon with similar microstructure to the metal possible. Copper covetic films exhibit greater transparency, higher conductivity, and resistance to oxidation than pure copper films of the same thickness, making them a suitable choice for transparent conductors.

  2. Preparation and Characterization of BPO Film as Electrode for Using of FeRAM

    Institute of Scientific and Technical Information of China (English)

    WEN Xin-Yi; YU Jun; WANG Yun-Bo; ZHOU Wen-Li; GAO Jun-Xiong; CHU Xiao-Hui

    2008-01-01

    Conductive perovskite BaPb03 (BPO) films as a potential electrode material of PZT capacitors used in ferroelectric random access memory are prepared by rf magnetron sputtering. An x-ray diffractometer and standard four probe method are employed to investigate the dependence of growth conditions on crystal structure and conductivity of BPO films. It is found that BPO films with perovskite phase can be obtained at substrate temperatures above 425℃, and the sample with the lowest resistivity is obtained at 450℃ under pure argon atmosphere. Using this BPO film as electrode, ferroelectric properties of BPO/PZT/BPO and Pt/PZT/BPO sandwiched structures are evaluated. Their remanent polarization and coercive field are 36.6μC/cm2 (81.3kV/cm) and 36.9μC/cm2 (89.1kV/cm), respectively. The coercive field of the former structure is lower than that of the latter, but remanent polarizations are almost the same. In addition, the results imply that BPO electrode is helpful to improve the fatigue resistance of PZT. The reasons are discussed.Supported by the National Natural Science Foundation of China under Grant Nos 90407023 and 60571009.

  3. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres.

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-04-21

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m(-1). During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □(-1) with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H₂O₂ electrode with a sensitivity of 0.56 mA mM(-1) cm(-2), a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM(-1) cm(-2) and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices. PMID:24615460

  4. Direct electrochemistry of hemoglobin entrapped in dextran film on carbon ionic liquid electrode

    Indian Academy of Sciences (India)

    Xiaoqing Li; Yan Wang; Xiaoying Sun; Tianrong Zhan; Wei Sun

    2010-03-01

    Direct electrochemistry of hemoglobin (Hb) entrapped in the dextran (De) film on the surface of a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) modified carbon paste electrode (CILE) has been investigated. UV-Vis and FT-IR spectroscopy showed that Hb retained its native structure in the De film. Scanning electron microscopy (SEM) indicated an uniform film was formed on the electrode surface. Cyclic voltammetric experiments indicated that the electron transfer efficiency between Hb and the electrode was greatly improved due to the presence of the De film and ionic liquid, which provided a biocompatible and higher conductive interface. A pair of well-defined and quasi-reversible redox peak was obtained with the anodic and cathodic peaks located at -0.195 V and -0.355 V in pH 7.0 phosphate buffer solution, respectively. The electrochemical parameters were calculated by investigating the relationship of the peak potential with the scan rate. The fabricated De/Hb/CILE showed good electrocatalytic ability to the reduction of H2O2 with the linear concentration range from 4.0 × 10-6 to 1.5 × 10-5 mol/L and the apparent Michaelis-Menten constant ($K_{M}^{\\text{app}}$) for the electrocatalytic reaction was calculated as 0.17 M.

  5. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres.

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-04-21

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m(-1). During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □(-1) with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H₂O₂ electrode with a sensitivity of 0.56 mA mM(-1) cm(-2), a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM(-1) cm(-2) and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.

  6. Unlinking absorption and haze in thin film silicon solar cells front electrodes

    OpenAIRE

    Boccard, Mathieu; Cuony, Peter; Battaglia, Corsin; Despeisse, Matthieu; Ballif, Christophe

    2010-01-01

    We study the respective influence of haze and free carrier absorption (FCA) of transparent front electrodes on the photogenerated current of micromorph thin film silicon solar cells. To decouple the haze and FCA we develop bi-layer front electrodes: a flat indium tin oxide layer assures conduction and allows us to tune FCA while the haze is adjusted by varying the thickness of a highly transparent rough ZnO layer. We show how a minimum amount of FCA leads only to a few percents absorption for...

  7. Development of New Electrode System for High Field Dielectric Properties Measurement Using Evaporated Polypropylene Thin Guard Film

    Science.gov (United States)

    Fujii, Masayuki; Tohyama, Kazuyuki; Tokoro, Tetsuro; Mizuno, Yukio; Nagao, Masayuki; Kosaki, Masamitsu

    Non-polar polymers such as polyethylene (PE) and polypropylene (PP) are widely used as very important electrical insulating and dielectric materials. They are used in the increasingly high AC electric field strength region approaching to the limit of electrical breakdown strength of the materials. Therefore the study of high-field dielectric property is very important in terms of understanding the AC breakdown mechanism of materials. A three-terminals electrode system with a guard film (new type electrode system) was developed in our laboratory for the precise measurement of high-field tanδ, where the guard film was used to reduce the disturbance of electric field around the edge of a main electrode. However, minute air sometimes steals between a sample film and the guard film. The air sometimes generates partial discharge in the high electric field region. Therefore, when the sample had minute air, the new type electrode system was limited under 100kVrms/mm application that didn't reach to an intrinsic breakdown strength of the 30μm-thick sample. We tried to improve the new electrode system without minute air between a sample film and the guard film. We also tried to make very thin guard film to reduce the field disturbance at the edge of main electrode. In this paper a PP-guard film on a biaxially oriented polypropylene (BOPP) film was made by evaporation. This improvement of the electrode system using the evaporated PP-guard film was in success so that high-field dielectric properties of BOPP film could be measured up to near the intrinsic breakdown field of the sample.

  8. Preparation of the nickel foam/Ni-Ce-Co-O film electrode by thermal decomposition for oxygen evolution reaction

    International Nuclear Information System (INIS)

    The Ni-Ce-Co-O film on nickel foam was prepared by thermal decomposition of acetates. The electrochemical activity of the film was affected by the temperature of thermal decomposition. Cerium ions introduced into the oxide film could increase the surface area and improve the oxygen evolution reaction (OER) activity of the electrode. Compared with thermal decomposition of nitrates, the OER activity of the film prepared with acetates was higher. When the nickel foam/Ni-Ce-Co-O film electrode prepared with acetates was used as the anode, in 30% KOH solution (88 ± 2 deg. C) at the current density of 4000 A/m2, the cell voltage was 250 mV lower than that of the nickel foam anode. Furthermore, the film electrode exhibited good stability

  9. Electrochromic properties of WO{sub 3} thin film onto gold nanoparticles modified indium tin oxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Deng Jiajia; Gu Ming [College of Chemistry, Chemical Engineering and Material Science, Soochow University, Suzhou Industrial Park, Suzhou, Jiangsu 215123 (China); Di Junwei, E-mail: djw@suda.edu.cn [College of Chemistry, Chemical Engineering and Material Science, Soochow University, Suzhou Industrial Park, Suzhou, Jiangsu 215123 (China)

    2011-04-15

    Gold nanoparticles (GNPs) thin films, electrochemically deposited from hydrogen tetrachloroaurate onto transparent indium tin oxide (ITO) thin film coated glass, have different color prepared by variation of the deposition condition. The color of GNP film can vary from pale red to blue due to different particle size and their interaction. The characteristic of GNPs modified ITO electrodes was studied by UV-vis spectroscopy, scanning electron microscope (SEM) images and cyclic voltammetry. WO{sub 3} thin films were fabricated by sol-gel method onto the surface of GNPs modified electrode to form the WO{sub 3}/GNPs composite films. The electrochromic properties of WO{sub 3}/GNPs composite modified ITO electrode were investigated by UV-vis spectroscopy and cyclic voltammetry. It was found that the electrochromic performance of WO{sub 3}/GNPs composite films was improved in comparison with a single component system of WO{sub 3}.

  10. Measurements of processes in ruthenium oxide film electrodes with the quartz-crystal microbalance technique

    International Nuclear Information System (INIS)

    The authors describe the first application of the quartz-crystal microbalance (QCM) technique for monitoring electrochemical processes in oxide film electrodes. They have investigated a film of ruthenium oxide, applied by the thermal decomposition of ruthenium chloride onto one side of the quartz-crystal. The quartz-crystal was precoated with gold keyhole patterns on both sides for inducing the 5 MHz resonance, followed by a thin Ti layer to ensure good adherence of the ruthenium oxide. Ruthenium oxide films are being investigated at Los Alamos for potential use in electrochemical capacitors. The material exhibits large charge capacity per geometric area and fast charge-discharge rates. Different possible processes can be responsible for charge compensation in such oxide materials, including those associated with simple double-layer charging, with pseudocapacitance, and with ion insertion into the small grains of the high-surface-area oxide material. The dynamics of such processes are determined, for a given oxide film, by the nature of the electrolyte and the resulting mechanism of charge-compensation. The QCM technique provides interesting information on these processes, as well as on film hydration and film dissolution process. The authors' initial results are presented in this paper. The results demonstrate the QCM as a sensitive tool for following not only ionic insertion processes during potential modulation, but also processes of film swelling and film dissolution

  11. Annealing Effect on the Structural and Optical Properties of Sputter-Grown Bismuth Titanium Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    José E. Alfonso

    2014-04-01

    Full Text Available The aim of this work is to assess the evolution of the structural and optical properties of BixTiyOz films grown by rf magnetron sputtering upon post-deposition annealing treatments in order to obtain good quality films with large grain size, low defect density and high refractive index similar to that of single crystals. Films with thickness in the range of 220–250 nm have been successfully grown. After annealing treatment at 600 °C the films show excellent transparency and full crystallization. It is shown that to achieve larger crystallite sizes, up to 17 nm, it is better to carry the annealing under dry air than under oxygen atmosphere, probably because the nucleation rate is reduced. The refractive index of the films is similar under both atmospheres and it is very high (n =2.5 at 589 nm. However it is still slightly lower than that of the single crystal value due to the polycrystalline morphology of the thin films.

  12. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Traulsen, Marie Lund; Norrman, Kion;

    2015-01-01

    Polarization induced changes in LSM electrode composition were investigated by utilizing in operando Raman spectroscopy and post mortem TOF-SIMS depth profiling. Experiments were conducted on cells with 160 nm thick (La0.85Sr0.15)0.9MnO3±δ thin film electrodes in 10% O2 at 700 °C under various......-surface region. Ex situ TOF-SIMS depth profiles were recorded through the LSM electrodes and revealed distinct compositional changes throughout the electrodes. The electrode elements and impurities separated into well-defined layers that were more stratified for stronger applied polarizations. The mechanism...

  13. In-situ Microscopic FT-IR Spectroelectrochemical Investigation of Polythiophene Film Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A polythiophene film was electrochemically deposited on a Pt micro-plate electrode and investigated by cyclic voltammetry and in-situ reflection microscopic FTIR spectroscopy. The FTIR analysis showed that the electropolymerization of thiophene on the Pt surface was affected by the surface adsorption processes of thiophene molecules. Two adsorption modes were identified. Two structure models of the polythiophene chain were observed simultaneously. It was proposed that the good conductibility of the polythiophene film was originated from a co-vibratory equilibrium of the link part of model Ⅰ and model Ⅱ.

  14. Transparent electrode requirements for thin film solar cell modules

    KAUST Repository

    Rowell, Michael W.

    2011-01-01

    The transparent conductor (TC) layer in thin film solar cell modules has a significant impact on the power conversion efficiency. Reflection, absorption, resistive losses and lost active area either from the scribed interconnect region in monolithically integrated modules or from the shadow losses of a metal grid in standard modules typically reduce the efficiency by 10-25%. Here, we perform calculations to show that a competitive TC must have a transparency of at least 90% at a sheet resistance of less than 10 Ω/sq (conductivity/absorptivity ≥ 1 Ω -1) for monolithically integrated modules. For standard modules, losses are much lower and the performance of alternative lower cost TC materials may already be sufficient to replace conducting oxides in this geometry. © 2011 The Royal Society of Chemistry.

  15. Electrochemical Sensor for Determination of Parathion Based on Electropolymerization Poly(Safranine Film Electrode

    Directory of Open Access Journals (Sweden)

    Xingyuan Liu

    2011-01-01

    Full Text Available Parathion has been determined with voltammetric technique based on a novel sensor fabricated by electropolymerization of safranine on a glassy carbon electrode (GCE. The electrochemical behavior of poly(safranine film electrode and its electrocatalytic activity toward parathion were studied in detail by cyclic voltammetry (CV and linear sweep voltammetry (LSV. All experimental parameters were optimized, and LSV was proposed for its determination. In optimal working conditions, the reduction current of parathion at this poly(safranine-modified electrode exhibited a good linear relationship with parathion concentration in the range of 3.43×10−8 to 3.43×10−5 mol L−1. The detection limit was 1.0×10−8 mol L−1. The high sensitivity and selectivity of the sensor were demonstrated by its practical application for the determination of trace amounts of parathion in fruit samples.

  16. Direct electrochemistry and electrocatalysis of myoglobin in dodecyltrimethylammonium bromide film modified carbon ceramic electrode

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhen Zhou; Hui Wang; She Ying Dong; An Xiang Tian; Zhi Xian He; Bin Chen

    2011-01-01

    Direct electrochemistry and electrocatalysis of myoglobin (Mb) were studied with Mb immobilized on dodecyltrimethylammonium bromide (DTAB) film modified carbon ceramic (CC) electrode. Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb (FeⅡ/FeⅢ) at about -0.3 V vs. SCE (pH = 6.98). The currents of the redox peak were linear to scan rate, and rate constant (Ks) was estimated to be 3.03 s-1. The formal potential (E01) of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of-36.44 mV/pH, implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2).

  17. A selective voltammetric detection for dopamine using poly(gallic acid) film modified electrode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The electrochemistry behavior of dopamine was investigated by cyclic voltammetry and differential pulse voltammetry at a poly (gallic acid) film modified glassy carbon electrode.Two electrons and two protons participated in the diffusion-controlled electrocatalytic oxidation of dopamine with a diffusion coefficient of 2.186×10~(-5) cm~2/s.The interference of ascorbic acid with the determination of dopamine could be efficiently eliminated.This work provided a simple approach to selectively and sensitively...

  18. Electrochemical oxygen transfer reaction on synthetic boron-doped diamond thin film electrode

    OpenAIRE

    Marselli, Béatrice; Comninellis, Christos

    2005-01-01

    Synthetic boron-doped diamond thin film is a new promising anode material. Because of its properties (high anodic stability under drastic conditions and wide potential window), it is widely investigated for numerous possible electrochemical applications such as electrosynthesis, preparation of powerful oxidants and electroincineration. In the first part of this work, simple charge transfer was investigated at boron-doped diamond electrode through the study of an outer sphere system in the pot...

  19. Development and characterization of fluorine tin oxide electrodes modified with high area porous thin films containing gold nanoparticles

    International Nuclear Information System (INIS)

    Different electrode materials are prepared using fluoride doped tin oxide (FTO) electrodes modified with high area porous thin films of metal oxides containing gold nanoparticles. Three different metal oxides (TiO2, MgO and SnO2) have been assayed to this end. The effect of the metal oxide nature and gold loading on the structure and performance of the modified electrodes was examined by Scanning Electron Microscopy, Transmission Electron Microscopy, X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy and electrochemical techniques. XRD measurements reveal that MgO electrodes present the smallest gold nanoparticles after the sintering step however, the electrochemical response of these electrodes shows important problems of mass transport derived from the high porosity of these materials (Brunauer Emmett Teller area of 125 m2/g). The excellent sintering properties of titania nanoparticles result in robust films attached to the FTO electrodes which allow more reliable and reproducible results from an electroanalytical point of view.

  20. Large-scale graphene-based composite films for flexible transparent electrodes fabricated by electrospray deposition

    Science.gov (United States)

    Kim, Woo Sik; Moon, Sook Young; Kim, Hui Jin; Park, Sungjin; Koyanagi, Jun; Huh, Hoon

    2014-12-01

    Large-scale transparent conducting electrodes were fabricated using the electrospray method on a glass wafer and polyethylene terephthalate film using chemically reduced graphene oxide and poly (3,4-ethylenedioxythiophene) (PEDOT). Graphene oxide (GO) is prepared by the modified Hummers method, and reduced GO (RG) is prepared at low temperature. By varying the concentration of RG and PEDOT of the composite material on the substrate, the electrical conductivity and transmittance of the electrode was controlled. The optical transmittance values of the graphene-based electrode at a wavelength of 550 nm were between 81 and 95% and had sheet resistances from 370 to 5400 Ω sq-1. After 1000 cycles of a bending test, the sheet resistances of the graphene-based composite films were unchanged. Different types of graphene and graphene-based electrodes were characterized by field-emission scanning electron microscopy, high-resolution transmission electron microscopy, high-resolution Raman spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, transmittance, and electrical conductivity measurements.

  1. Amperometric sensors based on sawdust film modified electrodes: application to the electroanalysis of paraquat.

    Science.gov (United States)

    Kenne Dedzo, Gustave; Nanseu-Njiki, Charles Péguy; Ngameni, Emmanuel

    2012-09-15

    Natural or sodium hydroxide treated Ayous sawdusts were used to prepare thin film electrodes (denoted respectively as PSTFE and SSTFE). The sensors obtained exhibit good mechanical stability and a wide electrochemical potential range. Their electrochemical characterization revealed that they present a good capacity to accumulate cations, but are not useful for the electroanalysis of anions. In all cases, the signals were more intense and well defined on SSTFE compared to PSTFE. When applied to the electroanalysis of paraquat, a significant improvement of the current intensities was obtained on these electrodes compared to the bare glassy carbon electrode. The diffusion of this compound through the film which is the main process governing the electrochemical reaction at the electrode surface, is 2.2 times more important with SSTFE compared to PSTFE. After the optimization of the detection parameters, calibration curves were obtained in the concentration range 0.1-0.725 μmol L(-1) for PSTFE and 0.05-0.6 μmol L(-1) for SSTFE. The detection limits determined for a signal/noise ratio=3 are 5.49×10(-9) mol L(-1) for PSTFE and 3.02×10(-9) mol L(-1) for SSTFE.

  2. An improved biosensor for acetaldehyde determination using a bienzymatic strategy at poly(neutral red) modified carbon film electrodes

    OpenAIRE

    Ghica, Mariana Emilia; Pauliukaite, Rasa; Marchand, Nicolas; Devic, Eric; Brett, Christopher M. A.

    2007-01-01

    Improved biosensors for acetaldehyde determination have been developed using a bienzymatic strategy, based on a mediator-modified carbon film electrode and co-immobilisation of NADH oxidase and aldehyde dehydrogenase. Modification of the carbon film electrode with poly(neutral red) mediator resulted in a sensitive, low-cost and reliable NADH detector. Immobilisation of the enzymes was performed using encapsulation in a sol-gel matrix or cross-linking with glutaraldehyde. The bienzymatic biose...

  3. Studies on the interfacial charge transfer processes of nanocrystalline CdSe thin film electrodes by intensity modulated photocurrent spectroscopy

    Institute of Scientific and Technical Information of China (English)

    张敬波; 林原; 尹峰; 肖绪瑞

    2000-01-01

    Interfacial charge transfer kinetics of the nanocrystalline CdSe thin film electrodes have been studied in sodium polysulfide solutions by intensity modulated photocurrent spectroscopy (IMPS). The interfacial direct and indirect charge transfer and recombination processes were analyzed in terms of the parameters: normalized steady state photocurrents and surface state lifetimes obtained by measuring the IMPS responses under different applied potentials and different solution concentrations. IMPS responses of polycrystalline CdSe thin film electrodes were also presented for comparison.

  4. Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

    Directory of Open Access Journals (Sweden)

    Shi C

    2010-01-01

    Full Text Available Abstract Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g−1 was observed for the sample with a specific mass of 89 μg cm−2 at a scan rate of 2 mV s−1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES.

  5. Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

    Science.gov (United States)

    Shi, C.; Zhitomirsky, I.

    2010-03-01

    Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0-3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC) in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g-1 was observed for the sample with a specific mass of 89 μg cm-2 at a scan rate of 2 mV s-1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES).

  6. Voltammetric determination of theophylline at a Nafion/multi-wall carbon nanotubes composite film-modified glassy carbon electrode

    Indian Academy of Sciences (India)

    Suling Yang; Ran Yang; Gang Li; Jianjun Li; Lingbo Qu

    2010-11-01

    A Nafion/multi-wall carbon nanotubes (MWNTs) composite film-modified electrode was fabricated and applied to the sensitive and convenient determination of theophylline (TP). Multi-wall carbon nanotubes (MWNTs) were easily dispersed homogeneously into 0.1% Nafion methanol solution by sonication. Appropriate amount of Nafion/MWNTs suspension was coated on a glassy carbon electrode. After evaporating methanol, a Nafion/MWNTs composite film-modified electrode was achieved. TP could effectively accumulate at Nafion/MWNTs composite film-modified electrode and cause a sensitive anodic peak at around 1180 mV (vs SCE) in 0.01 mol/L H2SO4 medium (pH 1.8). In contrast with the bare glassy carbon electrode, Nafion film-modified electrode, Nafion/MWNTs film-modified electrode could remarkably increase the anodic peak current and decreased the overpotential of TP oxidation. Under the optimized conditions, the anodic peak current was proportional to TP concentration in the range of 8.0 × 10-8-6.0 × 10-5 mol/L, with a detection limit of 2.0 × 10-8 mol/L. This newly developed method was used to determine TP in drug samples with good percentage of recoveries.

  7. Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jisheng

    1996-01-08

    This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

  8. Layer-by-Layer Assembly of Silicotungstate Multilayer Films Modified on Glassy Carbon Electrode and Their Electrochemical Behaviors

    International Nuclear Information System (INIS)

    A new electrode was modified by multilayer films composed of heteropolyanion (SiW12) and cationic polymer poly(diallyldimethylammonium chloride) through electrochemical growth. The modified electrode electrochemical behavior, the effect of solution ph and electrocatalytic response to the reduction of BrO3- and NO2- have been investigated. The result shows that the electrochemical process of multilayer films modified electrode including SiW12 is a reversible process by electrochemical step. One-electron process has no proton participation in the first step, and one-electron process is accompanied by one proton participation in the second step and two-electron process is accompanied by two protons participation in the third step. The films grow uniformly, and the peak currents increase with increasing layer numbers. The peak currents increase with scan rate, and the reduced potentials of multilayer films shift negatively with increasing pH. The electrochemical mechanism of multilayer films was suggested

  9. Unlinking absorption and haze in thin film silicon solar cells front electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Boccard, Mathieu; Cuony, Peter; Battaglia, Corsin; Despeisse, Matthieu; Ballif, Christophe [Ecole Polytechnique Federale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin Film Electronics Laboratory, Rue A.-L. Breguet 2, 2000 Neuchatel (Switzerland)

    2010-11-15

    We study the respective influence of haze and free carrier absorption (FCA) of transparent front electrodes on the photogenerated current of micromorph thin film silicon solar cells. To decouple the haze and FCA we develop bi-layer front electrodes: a flat indium tin oxide layer assures conduction and allows us to tune FCA while the haze is adjusted by varying the thickness of a highly transparent rough ZnO layer. We show how a minimum amount of FCA leads only to a few percents absorption for a single light path but to a strong reduction of the cell current in the infrared part of the spectrum. Conversely, a current enhancement is shown with increasing front electrode haze up to a saturation of the current gain. This saturation correlates remarkably well with the haze of the front electrode calculated in silicon. This allows us to clarify the requirements for the front electrodes of micromorph cells. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. A comparative investigation on structure and multiferroic properties of bismuth ferrite thin films by multielement co-doping

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Guohua; Tan, Guoqiang, E-mail: tan3114@163.com; Luo, Yangyang; Liu, Wenlong; Xia, Ao; Ren, Huijun

    2014-12-15

    Highlights: • Multielement (Tb, Cr and Mn) co-doped BiFeO{sub 3} films were fabricated by CSD method. • Multielement co-doping induces a structural transition. • It is found effective to stabilize the valence of Fe ions at +3 by the strategy. • The co-doping at A/B-sites gives rise to the superior multiferroic properties. - Abstract: (Tb, Cr and Mn) multielement co-doped BiFeO{sub 3} (BTFCMO) thin films were prepared by the chemical solution deposition method on fluorine doped tin oxide (FTO) substrates. X-ray diffraction, Rietveld refinement and Raman analyses revealed that a phase transition from rhombohedral to triclinic structure occurs in the multielement co-doped BiFeO{sub 3} films. It is found that the doping is conducive to stabilizing the valence of Fe ions and reducing leakage current. In addition, the highly enhanced ferroelectric properties with a huge remanent polarization (2P{sub r}) of 239.6 μC/cm{sup 2} and a low coercive field (2E{sub c}) of 615.6 kV/cm are ascribed to the well film texture, the structure transition and the reduced leakage current by the co-doping. Moreover, the structure transition is the dominant factor resulting in the significant enhancement observed in magnetization (M{sub s} ∼ 10.5 emu/cm{sup 3}), owing to the collapse of the space-modulated spin structure. In this contribution, these results demonstrate that the multielement co-doping is in favor of the enhanced multiferroic properties of the BFO films for possible multifunctional applications.

  11. Enhanced adhesion and conductivity of Cu electrode on AlN substrate for thin film thermoelectric device

    Science.gov (United States)

    Hu, Shaoxiong; Chen, Xin; Deng, Yuan; Wang, Yao; Gao, Hongli; Zhu, Wei; Cao, Lili; Luo, Bingwei; Zhu, Zhixiang; Ma, Guang; Han, Yu

    2015-02-01

    The Cu thin film electrode grown on aluminum nitride (AlN) substrate is widely used in the thin film thermoelectric devices due to its high electrical conductivity. We have developed a new type of buffer layer by co-sputtering Ti and Cu forming Ti-Cu layer. The Ti-Cu layer was sputtered on the Ti buffered AlN substrate so that the adhesion and electrical conductivity properties of the Cu film electrode on AlN substrate could be improved. The interface between the thin films and the substrate were characterized by the scanning electron microscope (SEM). Nanoscratch tests were conducted on a nanomechanical test system to investigate the adhesion between the Cu film electrodes and AlN substrate. Meanwhile, accelerated ageing test under thermal cycling was conducted to evaluate the reliability of the thin film electrode. The results show that the adhesion and the reliability of Cu film electrode on AlN substrate have been greatly improved by employing Ti-Cu/Ti buffer layers.

  12. Spin coated graphene films as the transparent electrode in organic photovoltaic devices

    International Nuclear Information System (INIS)

    Many research efforts have been devoted to the replacement of the traditional indium–tin-oxide (ITO) electrode in organic photovoltaics. Solution-based graphene has been identified as a potential replacement, since it has less than two percent absorption per layer, relative high carrier mobility, and it offers the possibility of deposition on large area and flexible substrates, compatible with roll to roll manufacturing methods. In this work, soluble reduced graphene films with high electrical conductivity and transparency were fabricated and incorporated in poly(3-hexylthiophene) [6,6]-phenyl-C61-butyric acid methyl ester photovoltaic devices, as the transparent electrode. The graphene films were spin coated on glass from an aqueous dispersion of functionalized graphene, followed by a reduction process combining hydrazine vapor and annealing under argon, in order to reduce the sheet resistance. The photovoltaic devices obtained from the graphene films showed lower performance than the reference devices with ITO, due to the higher sheet resistance (2 kΩ/sq) and the poor hydrophilicity of the spin coated graphene films.

  13. Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

    Science.gov (United States)

    Feng, Xiaojuan; Shi, Yanlong; Jin, Shuping

    2015-10-01

    The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g-1 at 0.3 A g-1 current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g-1), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

  14. Electrodeposition and Characterization of Bismuth Telluride Nanowires

    Science.gov (United States)

    Frantz, C.; Stein, N.; Gravier, L.; Granville, S.; Boulanger, C.

    2010-09-01

    In this work, we report thermoelectric measurements on electroplated bismuth telluride nanowires. Porous polycarbonate membranes, obtained by ion-track irradiation lithography, were chosen as electroplating templates. Bismuth telluride nanowires were achieved in acidic media under potentiostatic conditions at -100 mV versus saturated silver chloride electrode. The filling ratio of the pores was increased to 80% by adding dimethyl sulfoxide to the electrolyte. Whatever the experimental conditions, the nanowires were polycrystalline in the rhombohedral phase of Bi2Te3. Finally, the power output of arrays of bismuth telluride nanowires was analyzed as a function of load resistance. The results were strongly dependent on the internal resistance, which can be significantly reduced by the presence of dimethyl sulfoxide during electroplating.

  15. Control of thickness uniformity and grain size in graphene films for transparent conductive electrodes

    Science.gov (United States)

    Wu, Wei; Yu, Qingkai; Peng, Peng; Liu, Zhihong; Bao, Jiming; Pei, Shin-Shem

    2012-01-01

    Large-scale and transferable graphene films grown on metal substrates by chemical vapor deposition (CVD) still hold great promise for future nanotechnology. To realize the promise, one of the key issues is to further improve the quality of graphene, e.g., uniform thickness, large grain size, and low defects. Here we grow graphene films on Cu foils by CVD at ambient pressure, and study the graphene nucleation and growth processes under different concentrations of carbon precursor. On the basis of the results, we develop a two-step ambient pressure CVD process to synthesize continuous single-layer graphene films with large grain size (up to hundreds of square micrometers). Scanning electron microscopy and Raman spectroscopy characterizations confirm the film thickness and uniformity. The transferred graphene films on cover glass slips show high electrical conductivity and high optical transmittance that make them suitable as transparent conductive electrodes. The growth mechanism of CVD graphene on Cu is also discussed, and a growth model has been proposed. Our results provide important guidance toward the synthesis of high quality uniform graphene films, and could offer a great driving force for graphene based applications.

  16. Control of thickness uniformity and grain size in graphene films for transparent conductive electrodes

    International Nuclear Information System (INIS)

    Large-scale and transferable graphene films grown on metal substrates by chemical vapor deposition (CVD) still hold great promise for future nanotechnology. To realize the promise, one of the key issues is to further improve the quality of graphene, e.g., uniform thickness, large grain size, and low defects. Here we grow graphene films on Cu foils by CVD at ambient pressure, and study the graphene nucleation and growth processes under different concentrations of carbon precursor. On the basis of the results, we develop a two-step ambient pressure CVD process to synthesize continuous single-layer graphene films with large grain size (up to hundreds of square micrometers). Scanning electron microscopy and Raman spectroscopy characterizations confirm the film thickness and uniformity. The transferred graphene films on cover glass slips show high electrical conductivity and high optical transmittance that make them suitable as transparent conductive electrodes. The growth mechanism of CVD graphene on Cu is also discussed, and a growth model has been proposed. Our results provide important guidance toward the synthesis of high quality uniform graphene films, and could offer a great driving force for graphene based applications. (paper)

  17. Clean graphene electrodes on organic thin-film devices via orthogonal fluorinated chemistry.

    Science.gov (United States)

    Beck, Jonathan H; Barton, Robert A; Cox, Marshall P; Alexandrou, Konstantinos; Petrone, Nicholas; Olivieri, Giorgia; Yang, Shyuan; Hone, James; Kymissis, Ioannis

    2015-04-01

    Graphene is a promising flexible, highly transparent, and elementally abundant electrode for organic electronics. Typical methods utilized to transfer large-area films of graphene synthesized by chemical vapor deposition on metal catalysts are not compatible with organic thin-films, limiting the integration of graphene into organic optoelectronic devices. This article describes a graphene transfer process onto chemically sensitive organic semiconductor thin-films. The process incorporates an elastomeric stamp with a fluorinated polymer release layer that can be removed, post-transfer, via a fluorinated solvent; neither fluorinated material adversely affects the organic semiconductor materials. We used Raman spectroscopy, atomic force microscopy, and scanning electron microscopy to show that chemical vapor deposition graphene can be successfully transferred without inducing defects in the graphene film. To demonstrate our transfer method's compatibility with organic semiconductors, we fabricate three classes of organic thin-film devices: graphene field effect transistors without additional cleaning processes, transparent organic light-emitting diodes, and transparent small-molecule organic photovoltaic devices. These experiments demonstrate the potential of hybrid graphene/organic devices in which graphene is deposited directly onto underlying organic thin-film structures.

  18. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres

    Science.gov (United States)

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-03-01

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a sensitivity of 0.56 mA mM-1 cm-2, a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM-1 cm-2 and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a

  19. Anodic Oxidation in Aluminum Electrode by Using Hydrated Amorphous Aluminum Oxide Film as Solid Electrolyte under High Electric Field.

    Science.gov (United States)

    Yao, Manwen; Chen, Jianwen; Su, Zhen; Peng, Yong; Zou, Pei; Yao, Xi

    2016-05-01

    Dense and nonporous amorphous aluminum oxide (AmAO) film was deposited onto platinized silicon substrate by sol-gel and spin coating technology. The evaporated aluminum film was deposited onto the AmAO film as top electrode. The hydrated AmAO film was utilized as a solid electrolyte for anodic oxidation of the aluminum electrode (Al) film under high electric field. The hydrated AmAO film was a high efficiency electrolyte, where a 45 nm thick Al film was anodized completely on a 210 nm thick hydrated AmAO film. The current-voltage (I-V) characteristics and breakdown phenomena of a dry and hydrated 210 nm thick AmAO film with a 150 nm thick Al electrode pad were studied in this work. Breakdown voltage of the dry and hydrated 210 nm thick AmAO film were 85 ± 3 V (405 ± 14 MV m(-1)) and 160 ± 5 V (762 ± 24 MV m(-1)), respectively. The breakdown voltage of the hydrated AmAO film increased about twice, owing to the self-healing behavior (anodic oxidation reaction). As an intuitive phenomenon of the self-healing behavior, priority anodic oxidation phenomena was observed in a 210 nm thick hydrated AmAO film with a 65 nm thick Al electrode pad. The results suggested that self-healing behavior (anodic oxidation reaction) was occurring nearby the defect regions of the films during I-V test. It was an effective electrical self-healing method, which would be able to extend to many other simple and complex oxide dielectrics and various composite structures.

  20. Influence of Diffusion Plane Orientation on Electrochemical Properties of Thin Film LiCoO2 Electrodes

    NARCIS (Netherlands)

    Bouwman, P.J.; Boukamp, B.A.; Bouwmeester, H.J.M.; Notten, P.H.L.

    2002-01-01

    Submicrometer LiCoO2 films have been prepared on silicon substrates with RF sputtering and pulsed laser deposition (PLD). The electrochemical activity of both types of thin film electrodes is compared using scanning cyclic voltammetry, galvanostatic and potentiostatic intermittent titration, and ele

  1. Electrochemical quartz crystal microbalance study on the two-electrode-system cyclic voltammetric behavior of Prussian blue films

    Institute of Scientific and Technical Information of China (English)

    TAN YueMing; XIE QingJi; HUANG JinHua; CHEN DaiWu; CHEN Xin; TU XinMan; LI YunLong; GE Bin; YAO ShouZhuo

    2008-01-01

    A two-channel electrochemical quartz crystal microbalance (EQCM) was used to investigate the cyclic voltammetric behavior of two Prussian blue (PB) film-modified Au electrodes in a two-electrode con-figuration in aqueous solution. The redox peaks observed in the two-electrode cyclic voltammogram (CV) are assigned to the intrinsic redox transitions among the Everitt's salt, PB, and Prussian yellow for the film itself, the redox process of the Au substrate and the redox process of small-quantity ferri-/ferrocyanide impurities entrapped in the PB film, as also supported by ultraviolet-visible (UV-Vis) spectroelectrochemical data. The profile of the two-electrode solid-state CV for the PB powder sand-wiched between two gold-coated indium-tin oxide (ITO) electrodes is similar to that for two PB-modified Au electrodes in aqueous solution, implying similar origins for the corresponding redox peaks. The two-channel EQCM method is expected to become a highly effective technique for the studies of the two-electrode electrochemical behaviors of many other species/materials.Prussian blue (PB), two-electrode liquid#solid-state cyclic voltammetric behavior, two-channel electrochemical quartz crystal

  2. NiO/LaNiO3 film electrode with binder-free for high performance supercapacitor

    Science.gov (United States)

    Liu, Xi; Du, Guo; Zhu, Jiliang; Zeng, Zifan; Zhu, Xiaohong

    2016-10-01

    NiO/LaNiO3 (NiO/LNO) film electrode was prepared by spin-coating technique on Pt/Ti/SiO2/Si(100) substrates. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and cyclic charge-discharge measurements were employed to evaluate the electrochemical performance of the electrode. The effect of LNO layer on the performance of the NiO/LNO electrode was also investigated. The NiO/LNO electrode with appropriate LNO content possesses high specific capacitance (2030 F/g at 0.5 A/g) and good cyclability (specific capacitance retention of 83% after 1000 cycles). The present study suggests that NiO/LNO film is a promising electrode material for supercapacitor.

  3. [Preparation of NiAl-MMO Films Electrode and Its Capacitive Deionization Property].

    Science.gov (United States)

    Wang, Ting; Zhu, Chun-shan; Hu, Cheng-zhi

    2016-02-15

    Hydrotalcites are not only considered as important absorbents in water treatment and but also widely used as super capacitor materials. In this study, NiAl metal oxide (NiAl-MMO) films, which were the calcined products of hydrotalcite-like compounds, were grown on the surface of a foam nickel by an in-situ growth method using a foam nickel substrate as the nickel source. The prepared NiAl-MMO films electrodes materials had stable electrochemical capability, remarkable electrochemical capacitor, and gave a highest specific capacitance of 667 F x g(-1). The desalination performance of material indicated high voltage and weakly alkaline solution were favored for desalination. A highest desalination efficiency was up to 58.17% when the initial concentration of Cl- was 0.003 mol x L(-1), the voltage value was 1.0 V and pH value was 8. The adsorption saturated electrodes could be rapidly regenerated with a desorption rate of 87.96% by electrodes reversion. This study provides a new choice for desalination in wastewater treatment. PMID:27363150

  4. Preparation and characterization of chemically deposited nickel sulphide film and its application as a potential counter electrode

    Science.gov (United States)

    Ray, Jaymin; Patel, Mitesh; Ghediya, Prashant; Chaudhuri, Tapas K.

    2016-07-01

    Nickel sulphide (NiS) film has emerged as a counter electrode in many applications, such as thin film batteries, dye sensitized solar cells, and supercapacitors. In this regard, we report the direct liquid coating of pure hexagonal NiS films on glass using a precursor solution of nickel-thiourea complex. A uniform and void free film is observed using scanning electron microscopy. The room temperature electrical conductivity of ˜5 × 103 S cm-1 and the positive thermoelectric power (+6 μV K-1) specify p-type conduction. The temperature variation conductivity in the range 77-300 K depicts the transition of NiS films from conducting to semi-conducting behaviour at certain transition temperatures. Preliminary results from a cyclic voltammetry study shows the feasibility of NiS films as counter electrodes.

  5. Investigation of polyaniline films doped with Fe3+ as the electrode material for electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Highlights: • The PANI/Fe3+ films were synthesized by CV on stainless steel wire mesh. • The growth rate of PANI/Fe3+ films were greatly increased. • The PANI/Fe3+ films show a larger specific capacitance and lower resistance. • The relationship between electrochemical properties of a serious of transition metal ions doped PANI and the ratio of electronic affinity and ionic radius (Ea/r) has also been researched. - Abstract: H+ and Fe3+ ions co–doped polyaniline were synthesized by cyclic voltammetry onto the stainless steel mesh with various concentration of ferric chloride (FeCl3·6H2O) in electrolyte. The structure and morphology of PANI and PANI/Fe3+ films were characterized by Fourier transform infrared (FT–IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical properties of PANI and PANI/Fe3+ films were investigated by cyclic voltammetry, galvanostatic charge–discharge test and electrochemical impedance spectroscopy (EIS) in 0.5 mol L−1 H2SO4 electrolyte in three–electrode system. The PANI/0.2 M Fe3+ film shows a larger specific capacitance of 602 F g−1 at a current density of 3 mA/cm2 and lower resistance compared with the pure PANI film. The relationship between electrochemical properties of a serious of transition metal ions doped PANI/Mn+ (Mn+ = Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Fe3+) films and the ratio of electronic affinity and ionic radius (Ea/r) has also been researched

  6. Measurement of effective piezoelectric coefficients of PZT thin films for energy harvesting application with interdigitated electrodes.

    Science.gov (United States)

    Chidambaram, Nachiappan; Mazzalai, Andrea; Muralt, Paul

    2012-08-01

    Interdigitated electrode (IDE) systems with lead zirconate titanate (PZT) thin films play an increasingly important role for two reasons: first, such a configuration generates higher voltages than parallel plate capacitor-type electrode (PPE) structures, and second, the application of an electric field leads to a compressive stress component in addition to the overall stress state, unlike a PPE structure, which results in tensile stress component. Because ceramics tend to crack at relatively moderate tensile stresses, this means that IDEs have a lower risk of cracking than PPEs. For these reasons, IDE systems are ideal for energy harvesting of vibration energy, and for actuators. Systematic investigations of PZT films with IDE systems have not yet been undertaken. In this work, we present results on the evaluation of the in-plane piezoelectric coefficients with IDE systems. Additionally, we also propose a simple and measurable figure of merit (FOM) to analyze and evaluate the relevant piezoelectric parameter for harvesting efficiency without the need to fabricate the energy harvesting device. Idealized effective coefficients e(IDE) and h(IDE) are derived, showing its composite nature with about one-third contribution of the transverse effect, and about two-thirds contribution of the longitudinal effect in the case of a PZT film deposited on a (100)-oriented silicon wafer with the in-plane electric field along one of the Si directions. Randomly oriented 1-μm-thick PZT 53/47 film deposited by a sol-gel technique, was evaluated and yielded an effective coefficient e(IDE) of 15 C·m(-2). Our FOM is the product between effective e and h coefficient representing twice the electrical energy density stored in the piezoelectric film per unit strain deformation (both for IDE and PPE systems). Assuming homogeneous fields between the fingers, and neglecting the contribution from below the electrode fingers, the FOM for IDE structures with larger electrode gap is derived to be

  7. Direct Electrochemistry of Hemoglobin in Layer-by-layer {PDDA/Hb}n Films Assembled on Pyrolytic Graphite Electrodes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Layer-by-layer {PDDA/Hb}n films were assembled by means of alternate adsorption of positively charged poly(diallyldimethyl ammonium) (PDDA) and negatively charged hemoglobin (Hb) at pH 9.2 from their aqueous solutions on pyrolytic graphite (PG) electrodes. Film growth during adsorption cycles was demonstrated by cyclic voltammetry and UV-Vis spectroscopy.Direct electrochemistry of Hb in {PDDA/Hb} n films on PG was studied.

  8. [Desulphurization with multi-needle-water film electrodes by corona discharge].

    Science.gov (United States)

    Huang, Xu-ran; Li, Guo-feng; Li, Jie; Wu, Yan

    2008-09-01

    The study of this paper adopted stainless steel multi-needle as a high voltage electrode system, and water film as low voltage electrode. The electrodes were supplied with negative DC high voltage. Polluted gas containing sulfur dioxide (SO2) flowed into the corona discharge field from the center of the high voltage electrode system in an axis direction, then get across the water surface. Under the effect of corona discharge plasma and water absorption, SO2 was removed by converting it into sulfuric acid. The effect of the three factors which were the applied voltage, SO2 inlet concentration and duration of the exposure to the corona discharge on desulphurization efficiency has been studied mostly. Moreover, the concentrations of SO3(2-) and SO4(2-) ions in the water were measured and the mechanism of desulphurization was analyzed. The results showed that there was a synergistic effect on the removal of SO2 when combining corona discharge and water absorption, and both the desulphurization efficiency and the amount of sulfuric acid increased evidently. As the applied voltage and the duration increased, the desulphurization efficiency increased. Also, the SO2 inlet concentration had effect on desulphurization efficiency. When the SO2 inlet concentration was 430 x 10(-6), the voltage was 14.5 kV and the duration was 7.5 s, a desulphurization efficiency of more than 90% could be attained. PMID:19068659

  9. Electrocatalytic Hydrogen Evolution from Molybdenum Sulfide-Polymer Composite Films on Carbon Electrodes.

    Science.gov (United States)

    Lattach, Youssef; Deronzier, Alain; Moutet, Jean-Claude

    2015-07-29

    The design of more efficient catalytic electrodes remains an important objective for the development of water splitting electrolyzers. In this context a structured composite cathode material has been synthesized by electrodeposition of molybdenum sulfide (MoSx) into a poly(pyrrole-alkylammonium) matrix, previously coated onto carbon electrodes by oxidative electropolymerization of a pyrrole-alkylammonium monomer. The composite material showed an efficient electrocatalytic activity toward proton reduction and the hydrogen evolution reaction (HER). Data from Tafel plots have demonstrated that the electron transfer rate in the composite films is fast, in agreement with the high catalytic activity of this cathode material. Bulk electrolysis of acidic water at carbon foam electrodes modified with the composite have shown that the cathodes display a high catalytic activity and a reasonable operational stability, largely exceeding that of regular amorphous MoSx electrodeposited on naked carbon foam. The enhanced catalytic performances of the composite electrode material were attributed to the structuration of the composite, which led to a homogeneous distribution of the catalyst on the carbon foam network, as shown by SEM characterizations. PMID:26147828

  10. Vibration optimization of ZnO thin film bulk acoustic resonator with ring electrodes

    Science.gov (United States)

    Zhao, Zinan; Qian, Zhenghua; Wang, Bin

    2016-04-01

    A rectangular ZnO thin film bulk acoustic resonator with ring electrodes is presented in this paper to demonstrate the existence of a nearly uniform displacement distribution at the central part of this typical resonator. The variational formulation based on two-dimensional scalar differential equations provides a theoretical foundation for the Ritz method adopted in our analysis. The resonant frequencies and vibration distributions for the thickness-extensional modes of this ring electrode resonator are obtained. The structural parameters are optimized to achieve a more uniform displacement distribution and therefore a uniform mass sensitivity, which guarantee the high accuracy and repeatable measurement for sensor detection in an air or a liquid environment. These results provide a fundamental reference for the design and optimization of the high quality sensor.

  11. Layered conductive polymer on nylon membrane templates for high performance, thin-film supercapacitor electrodes

    Science.gov (United States)

    Shi, HaoTian Harvey; Naguib, Hani E.

    2016-04-01

    Flexible Thin-film Electrochemical Capacitors (ECs) are emerging technology that plays an important role as energy supply for various electronics system for both present era and the future. Intrinsically conductive polymers (ICPs) are promising pseudo-capacitive materials as they feature both good electrical conductivity and high specific capacitance. This study focuses on the construction and characterization of ultra-high surface area porous electrodes based on coating of nano-sized conductive polymer materials on nylon membrane templates. Herein, a novel nano-engineered electrode material based on nylon membranes was presented, which allows the creation of super-capacitor devices that is capable of delivering competitive performance, while maintaining desirable mechanical characteristics. With the formation of a highly conductive network with the polyaniline nano-layer, the electrical conductivity was also increased dramatically to facilitate the charge transfer process. Cyclic voltammetry and specific capacitance results showed promising application of this type of composite materials for future smart textile applications.

  12. Roll-to-Roll sputtered ITO/Cu/ITO multilayer electrode for flexible, transparent thin film heaters and electrochromic applications

    Science.gov (United States)

    Park, Sung-Hyun; Lee, Sang-Mok; Ko, Eun-Hye; Kim, Tae-Ho; Nah, Yoon-Chae; Lee, Sang-Jin; Lee, Jae Heung; Kim, Han-Ki

    2016-01-01

    We fabricate high-performance, flexible, transparent electrochromic (EC) films and thin film heaters (TFHs) on an ITO/Cu/ITO (ICI) multilayer electrode prepared by continuous roll-to-roll (RTR) sputtering of ITO and Cu targets. The RTR-sputtered ICI multilayer on a 700 mm wide PET substrate at room temperature exhibits a sheet resistance of 11.8 Ω/square and optical transmittance of 73.9%, which are acceptable for the fabrication of flexible and transparent EC films and TFHs. The effect of the Cu interlayer thickness on the electrical and optical properties of the ICI multilayer was investigated in detail. The bending and cycling fatigue tests demonstrate that the RTR-sputtered ICI multilayer was more flexible than a single ITO film because of high strain failure of the Cu interlayer. The flexible and transparent EC films and TFHs fabricated on the ICI electrode show better performances than reference EC films and TFHs with a single ITO electrode. Therefore, the RTR-sputtered ICI multilayer is the best substitute for the conventional ITO film electrode in order to realize flexible, transparent, cost-effective and large-area EC devices and TFHs that can be used as flexible and smart windows. PMID:27653830

  13. Disposable integrated bismuth citrate-modified screen-printed immunosensor for ultrasensitive quantum dot-based electrochemical assay of C-reactive protein in human serum

    Energy Technology Data Exchange (ETDEWEB)

    Kokkinos, Christos, E-mail: xkokkinos@gmail.com [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Prodromidis, Mamas [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Economou, Anastasios [Laboratory of Analytical Chemistry, Department of Chemistry, University of Athens, 157 71 Athens (Greece); Petrou, Panagiota; Kakabakos, Sotirios [Immunoassay/Immunosensors Lab, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR “Demokritos”, Aghia Paraskevi, 153 10 Athens (Greece)

    2015-07-30

    A novel immunosensor based on graphite screen-printed electrodes (SPEs) modified with bismuth citrate was developed for the voltammetric determination of C-reactive protein (CRP) in human serum using quantum dots (QDs) labels. The sandwich-type immunoassay involved physisorption of CRP capture antibody on the surface of the sensor, sequential immunoreactions with CRP and biotinylated CRP reporter antibody and finally reaction with streptavidin-conjugated PbS QDs. The quantification of the target protein was performed with acidic dissolution of the PbS QDs and anodic stripping voltammetric detection of the Pb(II) released. Detection was performed at bismuth nanodomains formed on the sensor surface during the electrolytic preconcentration step, as bismuth citrate was reduced to metallic bismuth simultaneously with the deposition of Pb on the surface of the immunosensor. Under optimal conditions, the response was linear over the range 0.2–100 ng mL{sup −1} CRP and the limit of detection was 0.05 ng mL{sup −1} CRP. Since the modified SPE serves as both the biorecognition element and the QDs reader, the analytical procedure is simplified, the drawbacks of existing electroplated immunosensors are minimized while the proposed disposable sensing platform provides convenient, low-cost and ultrasensitive detection of proteins and wider scope for mass-production. - Highlights: • A bismuth citrate-modified screen-printed immunosensor was developed. • PbS quantum dots labels were used in the sandwich immunoassay for CRP determination. • A Bi film was formed at the sensor surface during the preconcentration step of Pb. • The immunosensor minimizes the limitations of electroplated metal film electrodes.

  14. Disposable integrated bismuth citrate-modified screen-printed immunosensor for ultrasensitive quantum dot-based electrochemical assay of C-reactive protein in human serum

    International Nuclear Information System (INIS)

    A novel immunosensor based on graphite screen-printed electrodes (SPEs) modified with bismuth citrate was developed for the voltammetric determination of C-reactive protein (CRP) in human serum using quantum dots (QDs) labels. The sandwich-type immunoassay involved physisorption of CRP capture antibody on the surface of the sensor, sequential immunoreactions with CRP and biotinylated CRP reporter antibody and finally reaction with streptavidin-conjugated PbS QDs. The quantification of the target protein was performed with acidic dissolution of the PbS QDs and anodic stripping voltammetric detection of the Pb(II) released. Detection was performed at bismuth nanodomains formed on the sensor surface during the electrolytic preconcentration step, as bismuth citrate was reduced to metallic bismuth simultaneously with the deposition of Pb on the surface of the immunosensor. Under optimal conditions, the response was linear over the range 0.2–100 ng mL−1 CRP and the limit of detection was 0.05 ng mL−1 CRP. Since the modified SPE serves as both the biorecognition element and the QDs reader, the analytical procedure is simplified, the drawbacks of existing electroplated immunosensors are minimized while the proposed disposable sensing platform provides convenient, low-cost and ultrasensitive detection of proteins and wider scope for mass-production. - Highlights: • A bismuth citrate-modified screen-printed immunosensor was developed. • PbS quantum dots labels were used in the sandwich immunoassay for CRP determination. • A Bi film was formed at the sensor surface during the preconcentration step of Pb. • The immunosensor minimizes the limitations of electroplated metal film electrodes

  15. Electrochemical quartz crystal microbalance study on the two-electrode-system cyclic voltammetric behavior of Prussian blue films

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A two-channel electrochemical quartz crystal microbalance (EQCM) was used to investigate the cyclic voltammetric behavior of two Prussian blue (PB) film-modified Au electrodes in a two-electrode con-figuration in aqueous solution. The redox peaks observed in the two-electrode cyclic voltammogram (CV) are assigned to the intrinsic redox transitions among the Everitt’s salt, PB, and Prussian yellow for the film itself, the redox process of the Au substrate and the redox process of small-quantity ferri-/ferrocyanide impurities entrapped in the PB film, as also supported by ultraviolet-visible (UV-Vis) spectroelectrochemical data. The profile of the two-electrode solid-state CV for the PB powder sand-wiched between two gold-coated indium-tin oxide (ITO) electrodes is similar to that for two PB-modified Au electrodes in aqueous solution, implying similar origins for the corresponding redox peaks. The two-channel EQCM method is expected to become a highly effective technique for the studies of the two-electrode electrochemical behaviors of many other species/materials.

  16. Impedance analysis of different cell monolayers grown on gold-film electrodes.

    Science.gov (United States)

    Reiss, Bjoern; Wegener, Joachim

    2015-08-01

    Impedance analysis of mammalian cells grown on planar film electrodes provides a label-free, non-invasive and unbiased observation of cell-based assays addressing the biological response to drugs, toxins or stressors in general. Whereas the time course of the measured impedance at one particular frequency has been used a lot for quantitative monitoring, in-depth analysis of the frequency-dependent impedance spectra is rarely performed. This study summarizes and validates the existing model for spectral analysis by applying it to eight different cell types from different mammalian tissues. Model parameters correctly predict the functional and/or structural properties of the individual cells under study. PMID:26737923

  17. Film of lignocellulosic carbon material for self-supporting electrodes in electric double-layer capacitors

    Directory of Open Access Journals (Sweden)

    Tsubasa Funabashi

    2013-09-01

    Full Text Available A novel thin, wood-based carbon material with heterogeneous pores, film of lignocellulosic carbon material (FLCM, was successfully fabricated by carbonizing softwood samples of Picea jezoensis (Jezo spruce. Simultaneous increase in the specific surface area of FLCM and its affinity for electrolyte solvents in an electric double-layer capacitor (EDLC were achieved by the vacuum ultraviolet/ozone (VUV/O3 treatment. This treatment increased the specific surface area of FLCM by 50% over that of original FLCM. The results obtained in this study confirmed that FLCM is an appropriate self-supporting EDLC electrode material without any warps and cracks.

  18. Development of a Paper Actuator with PEDOT:PSS Thin-Films as An Electrode

    Directory of Open Access Journals (Sweden)

    Yusuke Hara

    2014-12-01

    Full Text Available A paper actuator was fabricated from poly(3,4-ethylenedioxythiophene doped with poly(4-styrenesulfonate (PEDOT:PSS by a wet process without organic solvents. The paper actuator had a capacitor structure, with a cationic polymer as an insulating layer sandwiched between two PEDOT:PSS films as the electrodes. The thickness of the paper actuator was approximately 36 mm. We measured its displacement as a function of applied voltage and frequency; the maximum displacement was 2.2 mm at 1.5 V and 1 Hz.

  19. Preparation of TiO2-based nanotubes/nanoparticles composite thin film electrodes for their electron transport properties

    International Nuclear Information System (INIS)

    The composite thin film electrodes were prepared with one-dimensional (1D) TiO2-B nanotubes (NTs) and zero-dimensional TiO2 nanoparticles (NPs) based on different weight ratios. The electron transport properties of the NTs/NPs composite thin film electrodes applied for dye-sensitized solar cells had been investigated systematically. The results indicated that although the amount of dye adsorption decreased slightly, the devices with the NTs/NPs composite thin film electrodes could obtain higher open-circuit voltage and overall conversion efficiency compared to devices with pure TiO2 NPs electrodes by rational tuning the weight ratio of TiO2-B NTs and TiO2 NPs. When the weight ratio of TiO2-B NTs in the NTs/NPs composite thin film electrodes increased, the density of states and recombination rate decreased. The 1D structure of TiO2-B NTs can provide direct paths for electron transport, resulting in higher electron lifetime, electron diffusion coefficient and electron diffusion length. The composite thin film electrodes possess the merits of the rapid electron transport of TiO2-B NTs and the high surface area of TiO2 NPs, which has great applied potential in the field of photovoltaic devices. - Highlights: • The composite thin film electrodes (CTFEs) were prepared with nanotubes and nanoparticles. • The CTFEs possess the rapid electron transport and high surface area. • The CTFEs exhibit lower recombination rate and longer electron life time. • The CTFEs have great applied potential in the field of photovoltaic devices

  20. MINIMUM SIZE OF 180 DEGREE DOMAINS IN FERROELECTRIC THIN FILMS COVERED BY ELECTRODES

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-qiu; LIU Yu-lan; WANG Biao

    2006-01-01

    Ferroelectric domain switching under low voltage or short pulses is of interest for the development of high-density random access memory (FRAM) devices. Being necessarily very small in size, instability and back switching often occur when the external voltage is removed, which creates serious problems. In this investigation, a general approach to determine the minimum size of ferroelectric domain to avoid back switching was developed, and as an example, a 180° domain in a ferroelectric thin film covered by the upper and lower electrodes was considered in detail. We note that our approach is generally applicable to many other fields, including phase transformation, nucleation and expansion of dislocation loops in thin films, etc.

  1. Electrical currents resulting from reduction/oxidation processes of tested particles on electrodes modified with metal-containing polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Malev, V.V., E-mail: elchem@rbcmail.r [Department of Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 Petergof, St. Petersburg (Russian Federation); Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St. Petersburg (Russian Federation); Levin, O.V. [Department of Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 Petergof, St. Petersburg (Russian Federation)

    2011-04-01

    Metal-containing films are considered as systems including a multitude of microelectrodes, the role of which is played by metal clusters distributed in both the film interior and film interfaces. In the case of electrode reactions occurring exclusively on the surface of such metal inclusions and the film thickness significantly exceeding clusters' radii, it is shown that the concentration of species participating in such processes (tested particles, further on) satisfies a diffusion equation complicated with an accompanying electrochemical reaction. By assuming reversibility of the electron transfer processes between polymer fragments, one can arrive at solutions of the derived equation and calculate the corresponding currents resulting from tested particles' reactions. The role of such factors of inclusion of metal clusters into conducting polymer films, as its density and inhomogeneity is discussed in the context of their influence on the measured currents of reduction/oxidation processes of tested particles. Non-stationary effects that might be observed in cycling voltammetry and potential clamp measurements with electrodes modified by metal-containing films are also analyzed. The performed analysis shows that electrochemical properties of the modified electrodes in question practically coincide with those of the electrodes made of the corresponding metals and immersed into the same solutions.

  2. Carbon paste electrode modified with duplex molecularly imprinted polymer hybrid film for metronidazole detection.

    Science.gov (United States)

    Xiao, Ni; Deng, Jian; Cheng, Jianlin; Ju, Saiqin; Zhao, Haiqing; Xie, Jin; Qian, Duo; He, Jun

    2016-07-15

    A novel electrochemical sensor based on duplex molecularly imprinted polymer (DMIP) hybrid film modified carbon paste electrode (CPE) has been developed for highly sensitive and selective determination of metronidazole (MNZ). A conductive poly(anilinomethyltriethoxysilane) film is firstly electrodeposited on the surface of a CPE, and then a molecularly imprinted polysiloxane (MIPS) membrane is covalently covered on the film via sol-gel process. The as-constructed DMIP hybrid film, combining the advantages of MIPS and conducting MIP, can make feasible the direct and efficient signal transformation between the target analyte and the transducer, as well as enhance the imprinting recognition capability, mass transfer efficiency and the detection sensitivity. Under optimized conditions, the reduction peak currents of MNZ are linear to MNZ concentrations in the range from 4.0×10(-7) to 2.0×10(-4) molL(-1) with a detection limit of 9.1×10(-8)molL(-1). The RSD values vary from 2.9% to 4.7% for intra-day and from 3.4% to 4.2% for inter-day precision. The DMIP-based sensor has been successfully applied for the determination of MNZ in biological and pharmaceutical samples. The accuracy and reliability of the method is further confirmed by high performance liquid chromatography. PMID:26921552

  3. 溶胶-凝胶法制备掺镧钛酸铋铁电薄膜%Preparation of Lanthanum Modified Bismuth Titanate Ferroelectric Thin Films by Sol-Gel Processing

    Institute of Scientific and Technical Information of China (English)

    喻驰; 朱建国; 肖定全; 袁小武; 朱基亮; 乐夕

    2001-01-01

    利用溶胶-凝胶法在Si(100)及Pt/Ti/Si(100)衬底上制备了Bi3.5La0.5Ti3O12(BLT-5)铁电薄膜,研究了在不同退火条件下BLT-5薄膜的结晶性能。经650℃、30 min退火处理的BLT-5铁电薄膜的矫顽场Ec=67 k V/cm,剩余极化强度Pr=11.2μC/cm2。BLT-5铁电薄膜呈现较好的抗疲劳特性,可望用于制备高容量铁电随机存取存储器。%Lanthanum modified bismuth titanate(Bi4-xLaxTi3O12,BLT-10x)ferroelectric thin films were prepared by Sol-Gel processing using tetrabyl titanate,bismuth nitrate and lanthanum nitrate.Polycrystalline BLT-5 thin films were obtained at relatively low annealing temperatures of 600~650℃.The typical cohesive electric field (Ec) and remnant polarization(Pt) for BLT-5 thin films annealed at 650℃,30 min were Ec=57 kV/cm,Px=11.2 μC/cm2.The BLT-5 thin films show good fatigue-free property and could be used in fabricating high density FRAM.

  4. Heterogeneous growth of anodic oxide film on a polycrystalline titanium electrode observed with a scanning electrochemical microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fushimi, Koji; Okawa, Tsuyoshi; Azumi, Kazuhisa; Seo, Masahiro

    2000-02-01

    A scanning electrochemical microscope (SECM) was applied to study anodic oxide film grown on a polycrystalline titanium electrode in deaerated pH 8.4 borate solution. The probe current images of SECM could detect the heterogeneous growth of anodic oxide film, depending on the substrate crystal grains. This heterogeneity increased with increasing the film formation potential at the potential higher than 3 V (SHE). The study of the dependence of film thickness on the substrate grain has been also supported with Raman microprobe spectroscopy.

  5. Micromorph thin-film silicon solar cells with transparent high-mobility hydrogenated indium oxide front electrodes

    OpenAIRE

    Battaglia, Corsin; Erni, Lukas; Boccard, Mathieu; Barraud, Loris; Escarré, Jordi; SöDerströM, Karin; Bugnon, Grégory; Billet, Adrian; Ding, Laura; Despeisse, Matthieu; Haug, Franz-Josef; De Wolf, Stefaan; Ballif, Christophe

    2011-01-01

    We investigate the performance of hydrogenated indium oxide as a transparent front electrode for micromorph thin-film silicon solar cells on glass. Light trapping is achieved by replicating the morphology of state-of-the-art zinc oxide electrodes, known for their outstanding light trapping properties, via ultraviolet nanoimprint lithography. As a result of the high electron mobility and excellent near-infrared transparency of hydrogenated indium oxide, the short-circuit current density of the...

  6. Studying the ion transfer across liquid interface of thin organic-film-modified electrodes in the presence of glucose oxidase

    OpenAIRE

    Mirceski, Valentin; Mitrova, Biljana; Ivanovski, Vladimir; Mitreska, Nikolina; Aleksovska, Angela; Gulaboski, Rubin

    2015-01-01

    A coupled electron-ion transfer reaction at thin organic-film-modified electrodes (TFE) is studied in the presence of glucose oxidase (GOx) under voltammetric conditions. TFE consists of a graphite electrode modified with a nitrobenzene solution of decamethylferrocene (DMFC) as a redox mediator and tetrabuthylammonium perchlorate as an organic-supporting electrolyte, in contact with aqueous buffer solutions containing percholarte ions and GOx. The redox turnover of DMFC coupled with perchl...

  7. Direct and Simultaneous Determination of Phenol, Hydroquinone and Nitrophenol at Boron-Doped Diamond Film Electrode

    Institute of Scientific and Technical Information of China (English)

    ZHAO, Guo-Hua; TANG, Yi-Ting; LIU, Mei-Chuan; LEI, Yan-Zhu; XIAO, Xiao-E

    2007-01-01

    The electrochemical characteristics of multi-component phenolic pollutants, such as phenol (Ph), hydroquinone (HQ) and 4-nitrophenol (4-NP), were investigated on boron-doped diamond (BDD) film electrode by differential pulse voltammetry (DPV) technique. A simple and feasible platform was accordingly established for the direct and simultaneous determination of these three phenolic pollutants. Results showed that, Ph, HQ and 4-NP gave obvious oxidation peaks on BDD electrode at the potential of 1.24, 0.76 and 1.52 V, respectively. Each of them displayed good linear relationship between their oxidation peak currents and their corresponding concentrations in a rather wide range coexisting with one or two of the other phenolic pollutants. The detection limits of Ph, HQ and 4-NP were estimated to be as low as 1.82×10-6, 1.67×10-6 and 1.44×10-6mol·L-1, respectively. Therefore, a promising direct and simultaneous electrochemical determination method of multi-component phenolic pollutants in wastewater samples was constructed successfully on BDD electrode with advantages being rapid, simple, convenient, sensitive, in situ and inexpensive.

  8. Electrochemical performance and stability of thin film electrodes with metal oxides in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wesselmark, M., E-mail: maria.wesselmark@ket.kth.s [Applied Electrochemistry, School of Chemistry and Chemical Engineering, KTH, SE-100 44 Stockholm (Sweden); Wickman, B. [Competence Centre for Catalysis, Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Lagergren, C.; Lindbergh, G. [Applied Electrochemistry, School of Chemistry and Chemical Engineering, KTH, SE-100 44 Stockholm (Sweden)

    2010-11-01

    Thin film electrodes are prepared by thermal evaporation of nanometer thick layers of metal oxide and platinum on a gas diffusion layer (GDL), in order to evaluate different metal oxides' impact on the activity and stability of the platinum cathode catalyst in the polymer electrolyte fuel cell. Platinum deposited on tin, tantalum, titanium, tungsten and zirconium oxide is investigated and the morphology and chemistry of the catalysts are examined with scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic sweeps in oxygen and nitrogen are performed prior and after potential cycling degradation tests. Platinum seems to disperse better on the metal oxides than on the GDL and increased electrochemically active surface area (ECSA) of platinum is observed on tin, titanium and tungsten oxide. A thicker layer metal oxide results in a higher ECSA. Platinum deposited on tungsten performs better than sole platinum in the polarisation curves and displays higher Tafel slopes at higher current densities than all other samples. The stability does also seem to be improved by the addition of tungsten oxide, electrodes with 3 nm platinum on 3, 10 and 20 nm tungsten oxide, performs better than all other electrodes after the accelerated degradation tests.

  9. The electrochemical preparation of FAD/ZnO with hemoglobin film-modified electrodes and their electroanalytical properties.

    Science.gov (United States)

    Lin, Kuo-Chiang; Chen, Shen-Ming

    2006-03-15

    Flavin adenine dinucleotide (FAD)-modified zinc oxide self-assembly films were prepared using repeated cyclic voltammetry. The electrochemical reaction of the hemoglobin with the FAD/ZnO self-assembly film-modified electrodes and their electrocatalytic properties were investigated. This paper describes the successful loading of the electrochemically active molecules of hemoglobin and FAD along with ZnO by electrochemical method. In addition to the cyclic voltammetry, an electrochemical quartz crystal microbalance was used to study the growth mechanism and the properties of the films. The FAD/zinc oxide films exhibited a single redox couple, which corresponded to the FAD redox couple. The electrocatalytic properties of the O2, H2O2, trichloroacetic acid and SO(3)2- were studied by the FAD/zinc oxide films in the absence or in the presence of hemoglobin. The electrocatalytic reduction current had been developed from the cathodic peak of the FAD/zinc oxide redox couple. The electrocatalytic process involved an interaction of hemoglobin and FAD/GC film-modified electrode to increase the electrocatalytic reduction current. The electrocatalytic reduction of O2 using the FAD/zinc oxide films was investigated by cyclic voltammetry and rotating ring-disk electrode methods.

  10. Nanocrystalline TiO2 thin film electrodes prepared by common pressure hydrothermal method at low temperature

    Institute of Scientific and Technical Information of China (English)

    LI Chengyu; LIN Yuan; LI Xueping; WANG Zhengping; MA Yutao; ZHOU Xiaowen; FENG Shujing; XIAO Xurui

    2005-01-01

    Nanocrystalline TiO2 thin film electrodes have been prepared from mixed pastes of tetrabutyl titanate and nanocrystalline TiO2 particles by common pressure hydrothermal method at low temperature. The tetrabutyl titanate was hydrolyzed and crystallized into anatase TiO2 to interconnect nanocrystalline TiO2 particles and adhere them to conductive substrates, obtaining highly porous and mechanically stable TiO2 nanocrystalline film. The conversion efficiencies of the dye-sensitized solar cells based on prepared electrodes on conductive glass substrates and flexible substrates were 4.8% and 1.9% under illumination of 100 mW/cm2, respectively.

  11. ELECTROCHEMICAL DETERMINATION OF ETHANOL, 2- PROPANOL AND 1-BUTANOL ON GLASSY CARBON ELECTRODE MODIFIED WITH NICKEL OXIDE FILM

    Directory of Open Access Journals (Sweden)

    A. Benchettara

    2014-12-01

    Full Text Available In this work, we present the modification of a glassy carbon electrode with nickel oxide film which is performed in two successive steps. In the first one, the electrochemical deposition of metallic nickel on the glassy carbon electrode (GCE is achieved in 0.1M boric acid; in the second step, the metallic deposit is anodically oxidized in 0.1M NaOH. These two operations were carried out in a three electrode cell with a filiform platinum auxiliary electrode, a SCE as potential reference and a working microelectrode of modified glassy carbon with nickel oxides. This electrode is characterized by several electrochemical techniques and is used for the catalytic determination of ethanol, 2-propanol and 1-butanol in 0.1 M NaOH. The proposed chemical mechanism shows that NiO2 acts as a mediator.

  12. ELECTROCHEMICAL DETERMINATION OF ETHANOL, 2- PROPANOL AND 1-BUTANOL ON GLASSY CARBON ELECTRODE MODIFIED WITH NICKEL OXIDE FILM

    Directory of Open Access Journals (Sweden)

    A. Benchettara

    2015-07-01

    Full Text Available In this work, we present the modification of a glassy carbon electrode with nickel oxide film which is performed in two successive steps. In the first one, the electrochemical deposition of metallic nickel on the glassy carbon electrode (GCE is achieved in 0.1M boric acid; in the second step, the metallic deposit is anodically oxidized in 0.1M NaOH. These two operations were carried out in a three electrode cell with a filiform platinum auxiliary electrode, a SCE as potential reference and a working microelectrode of modified glassy carbon with nickel oxides. This electrode is characterized by several electrochemical techniques and is used for the catalytic determination of ethanol, 2-propanol and 1-butanol in 0.1 M NaOH. The proposed chemical mechanism shows that NiO2 acts as a mediator.

  13. Top electrode material related bipolar memory and unipolar threshold resistance switching in amorphous Ta2O5 films

    Science.gov (United States)

    Cai, Yunyu; Sheng, Cuicui; Liang, Changhao

    2013-06-01

    Tantalum oxide (Ta2O5) is one of the most studied materials for its stable resistance switching and potential application in nonvolatile memory devices. Top electrode and essential switching material are two critical points dominating its switching characteristics. Here, Ta2O5 films of amorphous nature (a-Ta2O5) with tunable thicknesses were made by changing the applied voltage during anodic oxidation of Ta-metal foils. The resistance-switching behavior of an a-Ta2O5 film in a metal/a-Ta2O5/Ta configuration was investigated by using a sputtered W or Ag metal film as the top electrode. The unipolar threshold switching phenomenon was observed using W as top electrode (WTE), while bipolar switching behaviors were achieved using active Ag metal as top electrode (AgTE). The thickness of the a-Ta2O5 film shows an obvious effect on the SET voltage in a WTE/a-Ta2O5/Ta device. The interfacial redox reaction induced formation of more conductive Ta-rich suboxide and the Joule heating effect are proposed to contribute to the unipolar threshold switching behavior. It is also suggested that the bipolar switching could have resulted from the electrochemical reaction-induced dissolution and growth of Ag conducting channels inside the Ta2O5 films.

  14. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

    2015-08-31

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

  15. Combination of porous silica monolith and gold thin films for electrode material of supercapacitor

    Science.gov (United States)

    Pastre, A.; Cristini-Robbe, O.; Boé, A.; Raulin, K.; Branzea, D.; El Hamzaoui, H.; Kinowski, C.; Rolland, N.; Bernard, R.

    2015-12-01

    An all-solid electrical double layer supercapacitor was prepared, starting from a porous silica matrix coated with a gold thin-film. The metallization of the silica xerogel was performed by an original wet chemical process, based on the controlled growth of gold nanoparticles on two opposite faces of the silica monolith as a seed layer, followed by an electroless deposition of a continuous gold thin film. The thickness of the metallic thin film was assessed to be 700 nm. The silica plays two major roles: (1) it is used as a porous matrix for the gold electrode, creating a large specific surface area, and (2) it acts as a separator (non-metallized part of the silica). The silica monolith was soaked in a polyvinyl alcohol and phosphoric acid mixture which is used as polymer electrolyte. Capacitance effect was demonstrated by cyclic voltammetry experiments. The specific capacitance was found to be equal to 0.95 mF cm- 2 (9.5 F g-1). No major degradation occurs within more than 3000 cycles.

  16. Electrospray deposition of carbon nanotube thin films for flexible transparent electrodes.

    Science.gov (United States)

    Meng, Yinan; Xin, Guoqing; Nam, Jaewook; Cho, Sung Min; Chae, Heeyeop

    2013-09-01

    Flexible transparent carbon nanotube (CNT) electrodes were fabricated by electrospray deposition, a large-area scalable and cost-effective process. The carbon nanotubes were dispersed in N,N-dimethylformamide (DMF) and deposited on polyethylene terephthalate (PET) substrates by electrospray deposition process at room temperature and atmospheric pressure. Major process variables were characterized and optimized for the electrospray process development such as electric field between nozzle and substrates, CNT solution flowrate, gap between nozzle and substrates, solution concentration, solvent properties and surface temperature. The sheet resistance of the electrospray deposited CNT films were reduced by HNO3 doping process. 169 Omega/sq sheet resistance and 86% optical transmittance was achieved with low surface roughness of 1.2 nm. The films showed high flexibility and transparency, making them potential replacements of ITO or ZnO in such as solid state lighting, touch panels, and solar cells. Electrospray process is a scalable process and we believe that this process can be applied for large area carbon nanotube film formation. PMID:24205613

  17. Design and characterization of Ga-doped indium tin oxide films for pixel electrode in liquid crystal display

    International Nuclear Information System (INIS)

    Indium tin oxide (ITO) thin films doped with various metal atoms were investigated in terms of phase transition behavior and electro-optical properties for the purpose of upgrading ITO and indium zinc oxide (IZO) films, commonly used for pixel electrodes in flat panel displays. We explored Ce, Mg, Zn, and Ga atoms as dopants to ITO by the co-sputtering technique, and Ga-doped ITO films (In:Sn:Ga = 87.4:6.7:5.9 at.%) showed the phase transition behavior at 210 °C within 20 min with high visible transmittance of 91% and low resistivity of 0.22 mΩ cm. The film also showed etching rate similar to amorphous ITO, and no etching residue on glass surfaces. These results were confirmed with the film formed from a single Ga-doped ITO target with slightly different compositions (In:Sn:Ga = 87:9:4 at.%). Compared to the ITO target, Ga-doped ITO target left 1/4 less nodules on the target surface after sputtering. These results suggest that Ga-doped ITO films could be an excellent alternative to ITO and IZO for pixel electrodes in thin film transistor liquid crystal display (TFT-LCD). - Highlights: ► We report Ga-doped In–Sn–O films for a pixel electrode in liquid crystal display. ► Ga-doped In–Sn–O films show phase transition behavior at 210 °C. ► Ga-doped In–Sn–O films show high wet etchability and low resistivity

  18. Growth of anodic films on compound semiconductor electrodes: InP in aqueous (NH sub 4) sub 2 S

    CERN Document Server

    Buckley, D N

    2002-01-01

    Film formation on compound semiconductors under anodic conditions is discussed. The surface properties of InP electrodes were examined following anodization in a (NH sub 4) sub 2 S electrolyte. The observation of a current peak in the cyclic voltammetric curve was attributed to selective etching of the substrate and a film formation process. AFM images of samples anodized in the sulfide solution revealed surface pitting. Thicker films formed at higher potentials exhibited extensive cracking as observed by optical and electron microscopy, and this was explicitly demonstrated to occur ex situ rather than during the electrochemical treatment. The composition of the thick film was identified as In sub 2 S sub 3 by EDX and XPS. The measured film thickness varies linearly with the charge passed, and comparison between experimental thickness measurements and theoretical estimates for the thickness indicate a porosity of over 70 %. Cracking is attributed to shrinkage during drying of the highly porous film and does n...

  19. Electrical properties of (Ba, Sr)TiO3 thin films with Pt and ITO electrodes: dielectric and rectifying behaviour

    International Nuclear Information System (INIS)

    The electrical properties of (Ba, Sr)TiO3 (BST) thin films are studied using different combinations of Pt and tin-doped indium oxide (In2O3:Sn, ITO) as electrode material. With Pt as bottom and top electrode the films show insulating behaviour with a low leakage current. A rectifying current-voltage characteristic is obtained by replacing the top electrode with ITO. As shown by photoemission as well as by electrical measurements, the property of the BST/ITO interface depends strongly on the deposition sequence, and can be related to the level of oxidation of the ITO film. Highly doped ITO as top electrode forms an Ohmic contact with BST. This enables the preparation of highly rectifying diodes that exhibit a space-charge-limited current behaviour. Larger barriers are obtained when ITO is used as bottom electrode. This is related to the oxidation of the ITO layer during BST deposition and results in a low interface-limited current. Due to the large energy gaps of both BST and ITO, the combination of these materials provides an additional route to transparent electronics.

  20. Langmuir–Blodgett films of cholesterol oxidase and S-layer proteins onto screen-printed electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Guimarães, Juliana Aguilar, E-mail: helen@peq.coppe.ufrj.br; Ferraz, Helen Conceição; Alves, Tito Lívio Moitinho

    2014-04-01

    Graphical abstract: - Highlights: • Langmuir and LB monolayers of ChOx and S-layer proteins were obtained. • Mixed ChOx/S-layer proteins films presented an ideal-like behavior. • Modified sensor showed stable peaks with moderate intensity. • The type of LB deposition affects the sensor ability of detecting cholesterol. • Mixed ChOx/S-layer proteins LB films improve sensor properties. - Abstract: Stable Langmuir monolayers of cholesterol oxidase (ChOx) and S-layer proteins were produced at the water–air interface and subsequently transferred onto the surface of screen-printed carbon electrodes by the Langmuir–Blodgett (LB) technique. The modified electrode surface was characterized by atomic force microscopy (AFM) and cyclic voltammetry (CV). AFM indicated the presence of deposited layers, showing reduction of surface roughness (RMS and Rt parameters). Significant changes in the shape of CVs were observed in modified electrodes compared to bare electrodes. The anodic peaks could be observed in cyclic voltammograms (CV), at a scan rate equal to 25 mV s{sup −1}, using electrodes with Z-type LB deposition. The presence of S-layer proteins in the ChOx LB film increases the oxidation peak intensity and reduces the oxidation potential. Altogether, these results demonstrate the feasibility of producing a cholesterol biosensor based on the immobilization of ChOx and S-layer proteins by LB technique.

  1. ANODIC STRIPPING VOLTAMMETRY AT A MERCURY FILM ELECTRODE: BASELINE CONCENTRATIONS OF CADMIUM, LEAD, AND COPPER IN SELECTED NATURAL WATERS

    Science.gov (United States)

    A simple, rapid, and inexpensive anodic stripping voltammetric method with a mercury thin film electrode is reported for the establishment of baseline concentrations of cadmium, lead, and copper in natural waters. The procedure for routine surface preparation of wax-impregnated g...

  2. Increased charge storage capacity of titanium nitride electrodes by deposition of boron-doped nanocrystalline diamond films

    DEFF Research Database (Denmark)

    Meijs, Suzan; McDonald, Matthew; Sørensen, Søren;

    2015-01-01

    The aim of this study was to investigate the feasibility of depositing a thin layer of boron-doped nanocrystalline diamond (B-NCD) on titanium nitride (TiN) coated electrodes and the effect this has on charge injection properties. The charge storage capacity increased by applying the B-NCD film...

  3. Biocompatibility of Implantable Electrodes Coated with PVA Films in the Brain of Rats:a Histological Evaluation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qin; LI Tao; LI Chengyan; YE Ming; LU Yi; DUAN Yanwen

    2009-01-01

    The biocompatibility of silicone rubber(SR)based electrodes coating with poly (vinyl alcohol)(PVA)films after implanted in the brain of rats was investigated.Twenty-two Wistar rats were used and implanted with SR electrodes and PVA/PAA films coated electrodes in left and right cerebral cortex respectively.After 4 and 8 weeks,the expression of glial fibrillary acidic protein (GFAP,a specific marker of astrocytes)and cluster of differentiation 68(CD68,a specific marker of macrophages)were evaluated by immunohistochemistry.After 8 weeks,GFAP and CD68 expressions around PVA electrodes were significantly lower than those around SR electrodes in every stratified area(0-50μm,50-100μm,100μm from further up to the electrode-tissue interface).The results show that PVA coating can reduce the expressions of GFAP and CD68,suggesting the PVA coating can improve the biocompatibility of the SR while it is implanted in brain.

  4. Development and characterization of fluorine tin oxide electrodes modified with high area porous thin films containing gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Quintana, Carmen, E-mail: carmen.quintana@uam.e [Dpto. Quimica Analitica y Analisis Instrumental. Facultad de Ciencias. Universidad Autonoma de Madrid. Cantoblanco. 28049-Madrid (Spain); Atienzar, Pedro; Budroni, Gerolamo [Instituto de Tecnologia Quimica de Valencia, UPV-CSIC, Universidad Politecnica de Valencia, Av. de los Naranjos s/n, 46022-Valencia (Spain); Mora, Laura; Hernandez, Lucas [Dpto. Quimica Analitica y Analisis Instrumental. Facultad de Ciencias. Universidad Autonoma de Madrid. Cantoblanco. 28049-Madrid (Spain); Garcia, Hermenegildo; Corma, Avelino [Instituto de Tecnologia Quimica de Valencia, UPV-CSIC, Universidad Politecnica de Valencia, Av. de los Naranjos s/n, 46022-Valencia (Spain)

    2010-10-29

    Different electrode materials are prepared using fluoride doped tin oxide (FTO) electrodes modified with high area porous thin films of metal oxides containing gold nanoparticles. Three different metal oxides (TiO{sub 2}, MgO and SnO{sub 2}) have been assayed to this end. The effect of the metal oxide nature and gold loading on the structure and performance of the modified electrodes was examined by Scanning Electron Microscopy, Transmission Electron Microscopy, X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy and electrochemical techniques. XRD measurements reveal that MgO electrodes present the smallest gold nanoparticles after the sintering step however, the electrochemical response of these electrodes shows important problems of mass transport derived from the high porosity of these materials (Brunauer Emmett Teller area of 125 m{sup 2}/g). The excellent sintering properties of titania nanoparticles result in robust films attached to the FTO electrodes which allow more reliable and reproducible results from an electroanalytical point of view.

  5. Synthesis of Graphene Films by Chemical Vapor Deposition for Transparent Conducting Electrodes of GaN Light-Emitting Diodes

    Science.gov (United States)

    Jo, Gunho; Choe, Minhyeok; Cho, Chu-Young; Kim, Jin Ho; Park, Woojin; Lee, Sangchul; Park, Seong-Ju; Hong, Byung Hee; Kahng, Yung Ho; Lee, Takhee

    2011-12-01

    This work demonstrales large-scale simultaneous fabrication of patterned graphene-based GaN light-emitting diodes (LEDs). Graphene sheets were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized film properties, possessing a sheet resistance of ˜605 Ω/⃞ with a transparency of more than 85% in the 400-800 nm wavelength range, and was applied as transparent condueting electrodes of GaN-based blue LHDs, The light output performance of GaN LEDs with graphene electrodes was comparable to that of conventional ITO-electrode LEDs over the range of input current up to 150 mA.

  6. The fabrication and characterization of an ex situ plated lead film electrode prepared with the use of a reversibly deposited mediator metal

    Energy Technology Data Exchange (ETDEWEB)

    Tyszczuk, Katarzyna, E-mail: ktyszczuk@poczta.umcs.lublin.p [Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie Sklodowska Sq. 3, 20-031 Lublin (Poland)

    2011-04-15

    Research highlights: The lead film electrode prepared with use of the mediator metal was elaborated. The lead-based sensors were characterized by optical and voltammetric methods. The adsorptive system of folic acid was employed to investigate a new electrode. The application of the mediator metal improved properties of a lead film electrode. - Abstract: In this paper an ex situ plated lead film electrode prepared with use of the mediator metal (Zn) was elaborated. The electrochemical method for lead film formation is based on a co-deposition of a metal of interest (Pb) with a reversibly deposited mediator metal (Zn) and then on an oxidation of zinc and further deposition of lead by the appropriate potential. This serves to increase the density of islands of lead atoms, promoting lead film growth. The lead-based sensors were characterized by optical method (atomic force microscopy (AFM)) and as well as cyclic, linear sweep and square wave voltammetry. The adsorptive system of folic acid was employed to investigate the electrochemical characteristics a novel type of lead film electrode. Well-formed stripping peaks and a linear dependence of the stripping current on the folic acid concentration were observed on the lead film electrode prepared with use of the mediator metal while comparative measurements attempted with the lead film electrode prepared without use of the mediator metal were unsuccessful.

  7. The fabrication and characterization of an ex situ plated lead film electrode prepared with the use of a reversibly deposited mediator metal

    International Nuclear Information System (INIS)

    Research highlights: → The lead film electrode prepared with use of the mediator metal was elaborated. → The lead-based sensors were characterized by optical and voltammetric methods. → The adsorptive system of folic acid was employed to investigate a new electrode. → The application of the mediator metal improved properties of a lead film electrode. - Abstract: In this paper an ex situ plated lead film electrode prepared with use of the mediator metal (Zn) was elaborated. The electrochemical method for lead film formation is based on a co-deposition of a metal of interest (Pb) with a reversibly deposited mediator metal (Zn) and then on an oxidation of zinc and further deposition of lead by the appropriate potential. This serves to increase the density of islands of lead atoms, promoting lead film growth. The lead-based sensors were characterized by optical method (atomic force microscopy (AFM)) and as well as cyclic, linear sweep and square wave voltammetry. The adsorptive system of folic acid was employed to investigate the electrochemical characteristics a novel type of lead film electrode. Well-formed stripping peaks and a linear dependence of the stripping current on the folic acid concentration were observed on the lead film electrode prepared with use of the mediator metal while comparative measurements attempted with the lead film electrode prepared without use of the mediator metal were unsuccessful.

  8. Pyrolyzed Photoresist Carbon Electrodes for Trace Electroanalysis of Nickel(II

    Directory of Open Access Journals (Sweden)

    Ligia Maria Moretto

    2015-05-01

    Full Text Available Novel pyrolyzed photoresist carbon electrodes for electroanalytical applications have been produced by photolithographic technology followed by pyrolysis of the photoresist. A study of the determination of Ni(II dimethylglyoximate (Ni-DMG through adsorptive cathodic stripping voltammetry at an in situ bismuth-modified pyrolyzed photoresist electrode (Bi-PPCE is reported. The experimental conditions for the deposition of a bismuth film on the PPCE were optimized. The Bi-PPCE allowed the analysis of trace concentrations of Ni(II, even in the presence of Co(II, which is the main interference in this analysis, with cathodic stripping square wave voltammograms characterized by well-separated stripping peaks. The calculated limits of detection (LOD were 20 ng∙L−1 for Ni(II alone and 500 ng∙L−1 in the presence of Co(II. The optimized method was finally applied to the analysis of certified spring water (NIST1640a.

  9. Organic photovoltaic cells based on ZnO thin film electrodes.

    Science.gov (United States)

    Ghica, C; Ion, L; Epurescu, G; Nistor, L; Antohe, S; Dinescu, M

    2010-02-01

    Due to its wide band-gap (ca. 3.4 eV), ZnO is a possible candidate material to be used as transparent electrode for a new class of photovoltaic (PV) cells. Also, an increased interest for the photovoltaic properties of several organic monomers and polymers (merocyanines, phthalocyanines and porphyrins) was noticed, because of their high optical absorption in the visible region of the spectrum allowing them to be used as potential inexpensive materials for solar cells. Preparation and properties of CuPc (copper phthalocyanine) based photovoltaic cells using ZnO thin films as transparent conductor electrodes are presented in this paper. ZnO layers are grown by pulsed laser deposition, while the organic layers are obtained by thermal evaporation. Structural characterization is performed by electron microscopy. Optical and transport properties of the mutilayered structures are obtained by electrical and spectro-photometric measurements. The influence of the ZnO-polymer interface on the external quantum efficiency (EQE) of the photovoltaic cell is clearly evidenced by our measurements.

  10. Interconnection of multichannel polyimide electrodes using anisotropic conductive films (ACFs) for biomedical applications.

    Science.gov (United States)

    Baek, Dong-Hyun; Park, Ji Soo; Lee, Eun-Joong; Shin, SuJung; Moon, Jin-Hee; Pak, James Jungho; Lee, Sang-Hoon

    2011-05-01

    In this paper, we propose a method for interconnecting soft polyimide (PI) electrodes using anisotropic conductive films (ACFs). Reliable and automated bonding was achieved through development of a desktop thermocompressive bonding device that could simultaneously deliver appropriate temperatures and pressures to the interconnection area. The bonding conditions were optimized by changing the bonding temperature and bonding pressure. The electrical properties were characterized by measuring the contact resistance of the ACF bonding area, yielding a measure that was used to optimize the applied pressure and temperature. The optimal conditions consisted of applying a pressure of 4 kg f/cm(2) and a temperature of 180 °C for 20 s. Although ACF base bonding is widely used in industry (e.g., liquid crystal display manufacturing), this study constitutes the first trial of a biomedical application. We performed a preliminary in vivo biocompatibility investigation of ACF bonded area. Using the optimized temperature and pressure conditions, we interconnected a 40-channel PI multielectrode device for measuring electroencephalography (EEG) signals from the skulls of mice. The electrical properties of electrode were characterized by measuring the impedance. Finally, EEG signals were measured from the mice skulls using the fabricated devices to investigate suitability for application to biomedical devices.

  11. Interconnection of multichannel polyimide electrodes using anisotropic conductive films (ACFs) for biomedical applications.

    Science.gov (United States)

    Baek, Dong-Hyun; Park, Ji Soo; Lee, Eun-Joong; Shin, SuJung; Moon, Jin-Hee; Pak, James Jungho; Lee, Sang-Hoon

    2011-05-01

    In this paper, we propose a method for interconnecting soft polyimide (PI) electrodes using anisotropic conductive films (ACFs). Reliable and automated bonding was achieved through development of a desktop thermocompressive bonding device that could simultaneously deliver appropriate temperatures and pressures to the interconnection area. The bonding conditions were optimized by changing the bonding temperature and bonding pressure. The electrical properties were characterized by measuring the contact resistance of the ACF bonding area, yielding a measure that was used to optimize the applied pressure and temperature. The optimal conditions consisted of applying a pressure of 4 kg f/cm(2) and a temperature of 180 °C for 20 s. Although ACF base bonding is widely used in industry (e.g., liquid crystal display manufacturing), this study constitutes the first trial of a biomedical application. We performed a preliminary in vivo biocompatibility investigation of ACF bonded area. Using the optimized temperature and pressure conditions, we interconnected a 40-channel PI multielectrode device for measuring electroencephalography (EEG) signals from the skulls of mice. The electrical properties of electrode were characterized by measuring the impedance. Finally, EEG signals were measured from the mice skulls using the fabricated devices to investigate suitability for application to biomedical devices. PMID:21189231

  12. Novel amperometric sensor using metolcarb-imprinted film as the recognition element on a gold electrode and its application

    International Nuclear Information System (INIS)

    A molecularly imprinted film is electrochemically synthesized on a gold electrode using cyclic voltammetry to electropolymerize o-aminothiophenol in the presence of metolcarb (MTMC). The mechanism of the imprinting process and a number of factors affecting the activity of the imprinted film are discussed and optimized. Scanning electron microscope observations and binding measurements have proved that an MTMC-imprinted film (with a thickness of nearly 100 nm) was formed on the surface of the gold electrode. The film exhibited high binding affinity and selectivity towards the template MTMC, as well as good penetrability, reproducibility and stability. A novel amperometry sensor using the imprinted film as recognition element was developed for MTMC determination in food samples. Under the experimental conditions, the MTMC standard is linear within the concentration range studied (r2 = 0.9906). The limit of detection (S/N = 3) of the modified electrode was achieved to 1.34 x 10-8 mol L-1. Recoveries of MTMC from spiked apple juice, cabbage and cucumber samples for the developed electrochemical assay ranged from 94.80% to 102.43%, which was with great correlation coefficient (0.9929) with results from high-performance liquid chromatography. In practical application, the prepared amperometric sensor also showed good reproducibility and long lifetime for storage. The research in this study has offered a rapid, accurate and sensitive electrochemical method for quantitative determination of MTMC in food products.

  13. In-situ and ex-situ resistance measurements of polypyrrole film using double-band electrode

    Science.gov (United States)

    Cysewska, K.; Jasiński, P.

    2016-01-01

    Many in-situ techniques are performed in order to determine the resistance of conducting polymer film. However, the resistance measured in solution can be the combination of polymer resistance and that of other components, such as resistance of supporting electrolyte. Therefore, in this work, the influence of the solution on the resistance of polypyrrole (PPy) film has been studied. PPy film was electrchemically synthesized onto the iron double-band electrode in a one step process from an aqueous solution of 0.1 M pyrrole and 0.1 M sodium salicylate. Resistance determination of PPy film was based on impedance spectroscopy measurements and was performed in-situ, ex-situ and in a function of electrode potential. Based on these measurements electrical equivalent circuit of PPy coated Fe electrode in contact with solution or with the air have been studied. It was noticed that the concentration of electrolyte in measuring solution did not influence on the polymer resistance measured by in-situ technique. It was also noticed that measurements of polymer resistance conducted in- situ differ from that obtained in ex-situ experiments. The differences were related with the diffusion reactions occurring between the polymer film and air/solution.

  14. Removal of a hydrogenated amorphous carbon film from the tip of a micropipette electrode using direct current corona discharge.

    Science.gov (United States)

    Kakuta, Naoto; Okuyama, Naoki; Yamada, Yukio

    2010-02-01

    Micropipette electrodes are fabricated by coating glass micropipettes first with metal and then with hydrogenated amorphous carbon (a-C:H) as an electrical insulator. Furthermore, at the tip of the micropipette electrode, the deposited a-C:H film needs to be removed to expose the metal-coated surface and hollow for the purposes of electrical measurement and injection. This paper describes a convenient and reliable method for removing the a-C:H film using direct current corona discharge in atmospheric air. The initial film removal occurred at an applied voltage of 1.5-2.0 kV, accompanied by an abrupt increase in the discharge current. The discharge current then became stable at a microampere level in the glow corona mode, and the removed area gradually extended. PMID:20192514

  15. Fabrication of ordered NiO coated Si nanowire array films as electrodes for a high performance lithium ion battery.

    Science.gov (United States)

    Qiu, M C; Yang, L W; Qi, X; Li, Jun; Zhong, J X

    2010-12-01

    Highly ordered NiO coated Si nanowire array films are fabricated as electrodes for a high performance lithium ion battery via depositing Ni on electroless-etched Si nanowires and subsequently annealing. The structures and morphologies of as-prepared films are characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. When the potential window versus lithium was controlled, the coated NiO can be selected to be electrochemically active to store and release Li+ ions, while highly conductive crystalline Si cores function as nothing more than a stable mechanical support and an efficient electrical conducting pathway. The hybrid nanowire array films exhibit superior cyclic stability and reversible capacity compared to that of NiO nanostructured films. Owing to the ease of large-scale fabrication and superior electrochemical performance, these hybrid nanowire array films will be promising anode materials for high performance lithium-ion batteries.

  16. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H., E-mail: ted.sargent@utoronto.ca [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Kinge, Sachin [Advanced Technology, Materials and Research, Research and Development, Hoge Wei 33- Toyota Technical Centre, B-1930 Zaventem (Belgium)

    2015-10-12

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

  17. Composition and crystal structure of perovskite films attained from electrodes of used car battery

    Science.gov (United States)

    Dhiaputra, Ilham; Permana, Bayu; Maulana, Yusep; Inayatie, Yuniar Dwi; Purba, Yonatan R.; Bahtiar, Ayi

    2016-02-01

    Perovskite solar cells have been intensively investigated for high performance and low-cost solid-state solar cells. Perovskite based-lead materials are commonly used as active material for high power conversion efficiency solar cells. Herein, we report our study on the development of used electrodes car battery as a cheap raw lead material to be converted into lead (II) iodide PbI2 by using simple chemical method. We have successfully obtained PbI2 material with purity higher than 85% and its crystal structure is comparable with that of commercial product. The perovskite CH3NH3PbI3 film was prepared by spin-coating of PbI2 solution and followed by spin-coating two-times of methylamonium iodide (MAI) solution. In this paper, the crystal structure of perovskite film attained from used car battery is shown and compared with that of prepared from commercial PbI2. By utilizing the used car battery into perovskite valuable material for high performance solar cells, we can not only improve the economical value (added-value) of wasted car battery but also we can simultaneously save the environment.

  18. Electrical Properties of Al, Ag, Cu, Ti and SS Thin Film for Electrode of Solar Cell

    International Nuclear Information System (INIS)

    The Al, Ag, Cu, Ti and SS materials were deposited on the surface of glass substrate using plasma DC sputtering technique. The deposition process was done with the following plasma parameters : deposition time, gas pressure and substrate temperature with the aim to obtain a good conductance of thin films. Variation of substrate deposition time was 1 - 15 minutes, gas pressure was 5x10-2 - 7x10-2 torr and of temperature was 100 - 300 oC. The resistance measurement has been done by four points probes and the conductivity was calculated using mathematic formulation. It was obtained that the minimum resistance in the order of R = 0.07 Ω, was found at Ag materials and this was obtained at the following plasma parameters : deposition time 15 minutes, gas pressure 6x10-2 torr and temperature 300 oC, while, the resistance of : Cu, Al, Ti and SS materials were R = 0.13 Ω, R = 450 Ω, R = 633 Ω, R = 911 Ω respectively, It could be concluded that the Ag thin film has a minimum resistance, high conductivity compared to the other materials Al, Cu, Ti and SS. Ag is therefore the suitable material for applying as electrode of solar cell. (author)

  19. Electrochemical properties of tungsten oxysulphide thin films as positive electrodes for lithium microbatteries

    Indian Academy of Sciences (India)

    I Martin-Litas; P Vinatier; A Levasseur; J C Dupin; D Gonbeau

    2003-12-01

    Several WOS tungsten oxysulphide thin films were tested as positive electrodes for lithium microbatteries. The amorphous WO1.05S2 thin film was found very promising. A capacity decrease occurred during the first few cycles, after which the films were able to intercalate reversibly up to 1.1 lithium ion per formula unit under high regime (75 A/cm2). They were tested for 250 charge–discharge cycles, between 3.0 V and 1.2 V. X-ray photoelectron spectroscopy measurements were performed on different compounds in both intercalated (Li1WO1.05S2, Li2.7WO1.05S2 and Li3.8WO1.05S2) and partially de-intercalated (Li1WO1.05S2) states in order to understand the redox processes occurring during the first discharge–charge cycle. The analysis of both the W4 and the S2 peaks has shown that the redox processes involve not only the tungsten atoms but also sulphur atoms. At the beginning of the intercalation, W6+ was first partially reduced into W5+, and then into W4+, but the important stage was the reduction of W4+ into W0. In W0, the electron binding energy was very close to that of metallic tungsten. At the same time, S$^{2-}_2$ ions were partially reduced into S2- ions. But only the reduction process of tungsten atoms appeared to be totally reversible.

  20. Research Progress in Doping Modification of the Bismuth Ferrite Thin Film%BiFeO3多铁薄膜掺杂改性研究进展

    Institute of Scientific and Technical Information of China (English)

    张玉; 雷天宇; 任红; 孙远洋; 蔡苇; 符春林

    2015-01-01

    ABSTRACT:Bismuth ferrite is the only single phase multiferroic material at room temperature. It has broad application prospects in the fields of optoelectronic devices, spin electric devices, ferroelectric random access memories, magnetoelectric memory be-cause of its narrow band gap, large remnant polarization and high ferroelectric Curie temperature. However, the practical applica-tion of bismuth ferrite thin films is largely limited due to high leakage current and weak magnetic coupling. Ion doping is the most popular method because of its simplicity, easy to adjust microstructure and properties. This paper reviewed the research progress in doping modification of the electrical properties of bismuth ferrite thin films in recent years and the different types of doping, inclu-ding A-site ( trivalent Lanthanides and divalent alkali ions) , B-site ( such as transition metals) and A-B sites co-doping. The ele-ments in A-site and B-site doping were clarified based on the effects of doping on the leakage current, ferroelectricity and remnant polarization of bismuth ferrite films. And the effects and mechanisms of various types of doping were systemically summarized. Fi-nally, some urgent questions to be promptly solved were raised.%铁酸铋是目前发现的唯一的室温单相多铁性的材料,其禁带宽度较小,剩余极化强度较大,居里温度较高,在光电器件、自旋电子器件、铁电随机存储器、磁电存储单元等领域有着广阔的应用前景。但铁酸铋薄膜存在漏电流较大、磁电耦合性较弱等问题,制约了在实际中的应用。离子掺杂具有操作方便、易于实现薄膜的微结构及性能调控等优点,因而受到广泛关注。综述了国内外近年来关于铁酸铋薄膜电性能掺杂改性的相关工作,阐述了不同种类的掺杂,包括A位(三价镧系元素与二价碱金属元素)、B位(过渡金属元素等)以及AB位共掺杂,同时根据掺

  1. Combustion synthesized indium-tin-oxide (ITO) thin film for source/drain electrodes in all solution-processed oxide thin-film transistors

    Science.gov (United States)

    Tue, Phan Trong; Inoue, Satoshi; Takamura, Yuzuru; Shimoda, Tatsuya

    2016-06-01

    We report combustion solution synthesized (SCS) indium-tin-oxide (ITO) thin film, which is a well-known transparent conductive oxide, for source/drain (S/D) electrodes in solution-processed amorphous zirconium-indium-zinc-oxide TFT. A redox-based combustion synthetic approach is applied to ITO thin film using acetylacetone as a fuel and metal nitrate as oxidizer. The structural and electrical properties of SCS-ITO precursor solution and thin films were systematically investigated with changes in tin concentration, indium metal precursors, and annealing conditions such as temperature, time, and ambient. It was found that at optimal conditions the SCS-ITO thin film exhibited high crystalline quality, atomically smooth surface (RMS ~ 4.1 Å), and low electrical resistivity (4.2 × 10-4 Ω cm). The TFT using SCS-ITO film as the S/D electrodes showed excellent electrical properties with negligible hysteresis. The obtained "on/off" current ratio, subthreshold swing factor, subthreshold voltage, and field-effect mobility were 5 × 107, 0.43 V/decade, 0.7 V, and 2.1 cm2/V s, respectively. The performance and stability of the SCS-ITO TFT are comparable to those of the sputtered-ITO TFT, emphasizing that the SCS-ITO film is a promising candidate for totally solution-processed oxide TFTs.

  2. Fabrication and characterization of p+-i-p+ type organic thin film transistors with electrodes of highly doped polymer

    Science.gov (United States)

    Tadaki, Daisuke; Ma, Teng; Zhang, Jinyu; Iino, Shohei; Hirano-Iwata, Ayumi; Kimura, Yasuo; Rosenberg, Richard A.; Niwano, Michio

    2016-04-01

    Organic thin film transistors (OTFTs) have been explored because of their advantageous features such as light-weight, flexible, and large-area. For more practical application of organic electronic devices, it is very important to realize OTFTs that are composed only of organic materials. In this paper, we have fabricated p+-i-p+ type of OTFTs in which an intrinsic (i) regioregular poly (3-hexylthiophene) (P3HT) layer is used as the active layer and highly doped p-type (p+) P3HT is used as the source and drain electrodes. The 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) was used as the p-type dopant. A fabricating method of p+-i-p+ OTFTs has been developed by using SiO2 and aluminum films as capping layers for micro-scaled patterning of the p+-P3HT electrodes. The characteristics of the OTFTs were examined using the photoelectron spectroscopy and electrical measurements. We demonstrated that the fabricated p+-i-p+ OTFTs work with carrier injection through a built-in potential at p+/i interfaces. We found that the p+-i-p+ OTFTs exhibit better FET characteristics than the conventional P3HT-OTFT with metal (Au) electrodes, indicating that the influence of a carrier injection barrier at the interface between the electrode and the active layer was suppressed by replacing the metal electrodes with p+-P3HT layers.

  3. Enhanced sensitivity for biosensors: Functionalized P1,5-diaminonaphthalene-multiwall carbon nanotube composite film-modified electrode

    International Nuclear Information System (INIS)

    A homogeneous electroactive poly(1,5-diaminonaphthalene) (P1,5DAN) and multiwalled carbon nanotube (MWNT) composite film-modified electrode was fabricated by cyclic voltammetry and a casting method. The dispersion and morphology of the MWNTs/P1,5DAN composite film were investigated by scanning electron microscopy. The cyclic voltammograms of the electrode modified by the MWNTs/P15DAN composite film strongly depended on the film thickness and pH of the electrolyte solution. Two absolutely isolated oxidation potentials were found as the MWCNTs were immobilized onto the surface of P1,5DAN film in a pH 6.8 buffer solution containing ascorbic acid (AA) and uric acid (UA). Both peak currents linearly increased with increased concentrations. The electrochemical behavior of UA was not interrupted even in the presence of high-concentration AA given that AA had no observable electrochemical changes at the immobilized concentration. The electrocatalytic behavior of H2O2 was also investigated by steady-state amperometry for the immobilization of horseradish peroxidase on the P1,5DAN film. The plot of the response current vs. H2O2 concentration was linear over the wide concentration range of 0.015–5.37 mM.

  4. Preparation, characterization and electrocatalytic behavior of zinc oxide/zinchexacyanoferrate and ruthenium oxide hexacyanoferrate hybrid film-modified electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chu, H.-W.; Thangamuthu, R. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan (China); Chen, S.-M. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan (China)], E-mail: smchen78@ms15.hinet.net

    2008-02-15

    Polynuclear mixed-valent hybrid films of zinc oxide/zinchexacyanoferrate and ruthenium oxide hexacyanoferrate (ZnO/ZnHCF-RuOHCF) have been deposited on electrode surfaces from H{sub 2}SO{sub 4} solution containing Zn(NO{sub 3}){sub 2}, RuCl{sub 3} and K{sub 3}[Fe(CN){sub 6}] by potentiodynamic cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) measurements demonstrate the steady growth of hybrid film. Surface morphology of hybrid film was investigated using scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) data confirm existence of zinc oxide and ruthenium oxide hexacyanoferrate (RuOHCF) in the hybrid film. The effect of type of monovalent cations on the redox behavior of hybrid film was investigated. In pure supporting electrolyte, electrochemical responses of Ru{sup II/III} redox transition occurring at negative potential region resemble with that of a surface immobilized redox couple. The electrocatalytic activity of ZnO/ZnHCF-RuOHCF hybrid film was investigated towards oxidation of epinephrine, dopamine and L-cysteine, and reduction of S{sub 2}O{sub 8}{sup 2-} and SO{sub 5}{sup 2-} as well as IO{sub 3}{sup -} using cyclic voltammetry and rotating ring disc electrode (RRDE) techniques.

  5. Universal lab on a smartphone: a research of TiOPc thin film as a light dependence electrode

    Science.gov (United States)

    Lin, PoHan; Hsu, Y. H.; Lee, C. K.

    2014-02-01

    In this paper, we study the photoconductivity of a polymer-based TiOPc (Titanium Oxide Phthalocyanine) thin-film for the development of a multi-opto-piezoelectric-valve-array. Using a polymer-based TiOPc thin film to serve as the electrode and a structural layer of a piezoelectric polymer, P(VDF-TrFE) poly[(vinylidenefluoride-co-trifluoroethylene], an optical control valve-array could be developed for manipulating multiple microdroplets for the application of digital microfluidic. In this ongoing project, the dependency of the light intensity, thickness, and composition of spin-coated polymer-based TiOPc thin-film was studied. The experimental finding suggested that a 14 to 55 times resistivity change could be achieved by controlling the film thickness to be between 0.9 μm and 1.5 μm with TiOPc concentration of 20% and 30% w/w compositions.

  6. Thin Film Electrode Materials Li4Ti5O12 and LiCoO2 Prepared by Spray Pyrolysis Method

    International Nuclear Information System (INIS)

    The Li4Ti5O12 and the LiCoO2 have been considered as promising candidates of electrode materials for all-solid-state lithium secondary batteries. The spray pyrolysis method is a useful economical technique to prepare various thicknesses of oxide films though have not been intensively studied for fabrication of thin film lithium batteries. Thin films of Li4Ti5O12 and LiCoO2 electrode materials about 100-400 nm were prepared on quartz and gold substrates by the spray pyrolysis method by using Liacac and, TiO(acac)4 or Co(acac)3 with DMF solvent as starting materials. Electric properties as electrode materials for lithium batteries were estimated by using 3 probe liquid cells with liquid electrolyte LiPF6 in EC-DMC and Li metal as reference and counter electrodes. Structure and morphology of the films were investigated by XRD and SEM. Crystalline Li4Ti5O12 and LiCoO2 thin films were found to be prepared over 700 deg. C of substrate temperature. Cyclic voltammograms of the Li4Ti5O12 electrode thin films showed sharp oxidation and reduction peaks around 1.6 and 1.5 V, respectively. Charge-discharge curves for both Li4Ti5O12 and LiCoO2 electrode thin films showed discharge plateaus around 1.4 and 3.8 V with about 80 mAhg-1 of capacity. These results showed that these electrode thin films prepared by the spray pyrolysis method are electrochemically active and spray pyrolysis method is a promising technique to prepare thin film electrode materials.

  7. Magnetoconductance fluctuations in open bismuth quantum dots

    Science.gov (United States)

    Hackens, B.; Minet, J. P.; Farhi, G.; Crahay, A.; Faniel, S.; Gustin, C.; Bayot, V.

    2002-03-01

    We investigate the low temperature (300 mK - 10 K) magnetoconductance of open circular bismuth quantum dots (diameter: 500 nm). The structures are fabricated using a combination of electron beam lithography, lift off and plasma etching techniques on bismuth thin films evaporated on heated SiO2 substrates. We observe reproducible magnetoconductance fluctuations (UCFs) up to 5T, qualitatively similar to conductance fluctuations evidenced in open quantum dots patterned in high mobility semiconductor heterostructures. In our samples, UCFs are superposed on a slowly varying negative magnetoconductance background. We also observe a sharp conductance maximum centered in B=0, which is reminescent of the spin-orbit induced anti-localisation phenomenon. The behavior of UCFs and of the conductance maximum is discussed as a function of the temperature, thickness and degree of cristallinity of the cavity.

  8. Optical detection of ion diffusion in electrochromic poly(3,4-ethylenedioxy)thiophene film using microcantilever electrodes

    DEFF Research Database (Denmark)

    Lin, Rong; Stokbro, Kurt; Madsen, Dorte Nørgaard;

    2005-01-01

    We present measurements of microscale electrochromic switching of poly(3,4-ethylenedioxy)thiophene doped with poly(4-styrene sulfonate), thin film using microfabricated multi-point probe electrodes. After treatment with a dilute hydrochloric acid, a voltage bias above 3 V with respect to the ground...... potential of the film induced dark (light-absorbing) rings, which spread out from the anode on a time scale of seconds. The rate of expansion of the rings as well as the final diameter depended on the bias voltage. Using two micro four-point probes simultaneously, we measured with one probe the conductance...

  9. Fully transparent thin film transistors based on zinc oxide channel layer and molybdenum doped indium oxide electrodes

    Science.gov (United States)

    MÄ dzik, Mateusz; Elamurugu, Elangovan; Viegas, Jaime

    2016-03-01

    In this work we report the fabrication of thin film transistors (TFT) with zinc oxide channel and molybdenum doped indium oxide (IMO) electrodes, achieved by room temperature sputtering. A set of devices was fabricated, with varying channel width and length from 5μm to 300μm. Output and transfer characteristics were then extracted to study the performance of thin film transistors, namely threshold voltage and saturation current, enabling to determine optimal fabrication process parameters. Optical transmission in the UV-VIS-IR are also reported.

  10. In Search of the Holy Grail of Photoelectrochemistry: A Study of Thin Film Electrodes for Solar Hydrogen Generation

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Torbjoern

    2004-02-01

    Hydrogen is a wanted energy carrier in a future society less dependent of fossil fuels. This thesis investigates the possibilities of using solar energy to convert water into hydrogen and oxygen, so called artificial photosynthesis. Through this work multiple inexpensive and stable thin film semiconductor electrodes have been produced and used as solar energy absorbers and active sites for direct watersplitting in photoelectrochemical cells. The electrodes have mainly been of nanostructured metal oxide character but also nitrides have been studied. Detailed back ground theory on photoelectrochemistry of semiconductors for hydrogen evolution is given in the summary of the thesis. Nanostructured WO{sub 3} electrodes with a quantum yield close to unity were designed and photoelectrochemically characterized. Hematite, a-Fe{sub 2}O{sub 3}, nanorods were synthesized and characterized for the aim of water oxidation. The morphology of the hematite nanorods was found to be in favor of the traditional isotropic nanostructured electrodes. Moreover, a unique porous nitrogen doped TiO{sub 2} material, photoactive in visible light, was obtained by reactive sputtering. The nitrogen doped material has interesting photoelectrochemical properties and is also promising for related applications such as pollution degradation by photocatalysis. Polycrystalline indium nitride, InN, was produced by reactive sputtering. Electrodes of the as prepared InN as well as electrodes annealed in nitrogen were studied for the aim of photooxidation of water. The electrodes studied are interesting candidates as potential watersplitting electrodes in photoelectrochemical cells, even if all had in common that further improvements and optimizations need to be done.

  11. Self-passivated copper as a gate electrode in a poly-Si thin film transistor liquid crystal display

    International Nuclear Information System (INIS)

    Self-passivated copper as a gate electrode in the form of TiO/Cu/TiO/TiN/SiO2 has been obtained by annealing Cu/Ti/TiN/SiO2. The thickness of Ti in Cu/TiTiN was optimized at 150 Aa by forming an 80 Aa continuous TiO film on the outer surface of the Cu. The multilayer of SiO2/TiO/Cu/TiO/TiN/SiO2 showed stable electrical passivating properties against Cu diffusion into the top or bottom SiO2. Consequently, self-passivated copper has secured the dielectric properties of plasma enhanced chemical vapor deposition SiO2 and can be utilized as a gate electrode in low temperature poly-Si thin film transistor liquid crystal displays without sacrificing the low resistivity of Cu. [copyright] 2001 American Institute of Physics

  12. Dielectric dispersion of BaxSr1-xTiO3 thin film with parallel-plate and coplanar interdigital electrodes

    Science.gov (United States)

    Zhang, Xiao-Yu; Song, Qing; Xu, Feng; Sheng, Su; Wang, Peng; Ong, C. K.

    2009-03-01

    Ferroelectric BaxSr1-xTiO3 (BST) thin films with x = 0.25 and 0.5 were grown by pulsed laser deposition on single crystal LaAlO3 and Pt/Ti/SiO2/Si substrates, respectively. Capacitors were then fabricated from the BST thin films based on coplanar interdigital electrodes (CIEs) and parallel-plate electrodes (PPEs). The dielectric properties of the BST film with CIE and PPE were investigated and compared over a wide frequency range from 100 Hz to 10 GHz. The dielectric dispersion in PPE configuration, caused by the interfacial polarization in film/electrode interfaces, exhibited a strong dependence on frequency. However, the permittivity ɛCIE in CIE configuration shows a gentle variation with the frequency indicating interfacial polarization substantially suppressed. The influence upon the dielectric properties of the columnar BST grains due to the use of different forms of electrodes was discussed.

  13. Dielectric dispersion of BaxSr1-xTiO3 thin film with parallel-plate and coplanar interdigital electrodes

    International Nuclear Information System (INIS)

    Ferroelectric BaxSr1-xTiO3 (BST) thin films with x = 0.25 and 0.5 were grown by pulsed laser deposition on single crystal LaAlO3 and Pt/Ti/SiO2/Si substrates, respectively. Capacitors were then fabricated from the BST thin films based on coplanar interdigital electrodes (CIEs) and parallel-plate electrodes (PPEs). The dielectric properties of the BST film with CIE and PPE were investigated and compared over a wide frequency range from 100 Hz to 10 GHz. The dielectric dispersion in PPE configuration, caused by the interfacial polarization in film/electrode interfaces, exhibited a strong dependence on frequency. However, the permittivity εCIE in CIE configuration shows a gentle variation with the frequency indicating interfacial polarization substantially suppressed. The influence upon the dielectric properties of the columnar BST grains due to the use of different forms of electrodes was discussed.

  14. Characterisation of poly(neutral red) modified carbon film electrodes; application as a redox mediator for biosensors

    OpenAIRE

    Pauliukaite, Rasa; Ghica, Mariana; Barsan, Madalina; Brett, Christopher

    2007-01-01

    Abstract The polymer redox mediator, poly(neutral red) (PNR), has been synthesised and characterised electrochemically to investigate the best electropolymerisation and mediation conditions for application in enzyme biosensors and to clarify the mechanism of action. Neutral red was electropolymerised by potential cycling on carbon film electrode substrates by allowing the monomer to be oxidised during the full 20 cycles of polymerisation or reducing the positive limit of the potential window...

  15. Thiol anchoring and catalysis of gold nanoparticles at the liquid interface of thin-organic film-modified electrodes

    OpenAIRE

    Mirceski, Valentin; Aleksovska, Angela; Pejova, Biljana; Ivanovski, Vladimir; Mitrova, Biljana; Mitreska, Nikolina; Gulaboski, Rubin

    2014-01-01

    The deposition of in-situ formed gold nanoparticles at the liquid/liquid (L/L) interface is studied by means of thin-organic-film-modified electrodes (TFE). The degree of ordering and aggregation of gold nanoparticles can be tuned by adding a lipophilic and hydrophilic thiol in the organic and aqueous phase, respectively. The ordered thiol-anchored gold nanoparticles exhibit pronounced catalytic effect toward electron-transfer reactions across the L/L interface.

  16. Electrochemical dechlorination of chloroform in neutral aqueous solution on palladium/foam-nickel and palladium/polymeric pyrrole film/foam-nickel electrodes

    Institute of Scientific and Technical Information of China (English)

    SUN Zhirong; LI Baohua; HU Xiang; SHI Min; HOU Qingnan; PENG Yongzhen

    2008-01-01

    Electrochemical dechlonnafion of chloroform in neutral aqueous solution was investigated using palladium-loaded electrodes at ambient temperature.Palladium/foam-nickel (Pd/foam-Ni) and palladium/polymeric pyrrole film/foam-nickel (Pd/PPy/foam-Ni)composite electrodes which provided catalytic surface for reductive dechiorination of chloroform in aqueous solution were prepared using an electrodepositing method.Scanning electron microscope (SEM) micrographs showed that polymeric pyrrole film modified the electrode-surface characteristics and resulted in the uniform dispersion of needle-shaped palladium particles on foam-Ni supporting electrode.The experimental results of dechlorination indicated that the removal efficiency of chloroform and current efficiency in neutral aqueous solution on Pd/PPy/foam-Ni electrode could be up to 36.8% and 33.0% at dechlorination current of 0.1 mA and dechlorination time of 180 rain,which is much higher than that of Pd/foam-Ni electrode.

  17. Microwave-assisted low temperature fabrication of ZnO thin film electrodes for solar energy harvesting

    International Nuclear Information System (INIS)

    Metallic Zn thin films were electrodeposited on fluorine-doped tin oxide (FTO) glass substrates and oxidized under air by conventional radiant and microwave post-annealing methods to obtain ZnO thin film electrodes. The temperature of each post-annealing method was varied systematically and the photoelectrochemical (PEC) performance of electrodes was evaluated. The best photocurrent density achieved by the conventional radiant annealing method at 425 °C for 15 min was 93 μA cm−2 at 1.23 V vs. NHE and the electrode showed an incident photon-to-electron conversion efficiency (IPCE) of 28.2%. X-ray diffractogram of this electrode showed that the oxidation of Zn to ZnO was not completed during the radiant annealing process as evident by the presence of metallic Zn in the electrode. For the electrode oxidized from Zn to ZnO under microwave irradiation, a photocurrent of 130 μA cm−2 at 1.23 V vs. NHE and IPCE of 35.6% was observed after annealing for just 3 min, during which the temperature reached 250 °C. The photocurrent was 40% higher for the microwave annealed sample; this increase was attributed to higher surface area by preserving the nanostructure, confirmed by SEM surface topographical analysis, and better conversion yields to crystalline ZnO. Overall, it was demonstrated that oxidation of Zn to ZnO can be accomplished by microwave annealing five times faster than that of conventional annealing, thus resulting in a ~ 75% power saving. This study shows that microwave processing of materials offers significant economic and performance advantages for industrial scale up. - Highlights: • Conversion of Zn to ZnO by microwave and radiant annealing was conducted. • Microwave conversion was 5 times faster compared to radiant annealing. • Photoelectrochemical performance of microwave annealed ZnO was 40% higher. • Microwave annealing results in a 75% energy saving

  18. Voltammetric method for sensitive determination of herbicide picloram in environmental and biological samples using boron-doped diamond film electrode

    International Nuclear Information System (INIS)

    The voltammetric behavior and determination of picloram, a member of a pyridine herbicide family, was for the first time investigated on a boron doped diamond film electrode using cyclic and differential pulse voltammetry. The influence of supporting electrolyte and scan rate on the current response of picloram was examined to select the optimum experimental conditions. It was found that picloram provided one well-shaped oxidation peak at very positive potential (+1.5 V vs. Ag/AgCl electrode) in strong acidic medium. At optimized differential pulse voltammetric parameters, the current response of picloram was proportionally linear in the concentration range from 0.5 to 48.07 μmol L−1 and the low limit of detection of 70 nmol L−1 as well as good repeatability (relative standard deviation of 2.6% at 10 μmol L−1 for n = 11) were obtained on unmodified boron-doped diamond film electrode. The proposed method was successfully applied in analysis of environmental (tap and natural water) and biological (human urine) samples spiked with picloram with good accuracy (relative standard deviations less than 5% for all samples, n = 5). By this way, the boron-doped diamond could introduce a green (environmentally acceptable) alternative to mercury electrodes for the monitoring of herbicides

  19. CHROMIUM ELECTROANALYSIS AT SCREEN PRINTED ELECTRODE MODIFIED BY THIN FILMS OF NICKEL

    Science.gov (United States)

    A rapid and potentially cost-effective electrochemical method is reported for analysis of chromium (VI) and Chromium(III) using a nickel modified screen printed carbon ink electrode. Electrochemical characteristics of nickel modified electrode as well voltammetric behavior f...

  20. Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

    International Nuclear Information System (INIS)

    Nanostructured cerium oxide (CeO2) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO3)3·6H2O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO2 and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO2/TCO film to form the lipase/nano-CeO2/TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO2/TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO2/TCO film and hence the lipase/nano-CeO2/TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6 weeks. Highlights:

  1. Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

    Energy Technology Data Exchange (ETDEWEB)

    Panky, Sreedevi; Thandavan, Kavitha [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sivalingam, Durgajanani [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sethuraman, Swaminathan; Krishnan, Uma Maheswari [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Jeyaprakash, Beri Gopalakrishnan [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Rayappan, John Bosco Balaguru, E-mail: rjbosco@ece.sastra.edu [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India)

    2013-01-15

    Nanostructured cerium oxide (CeO{sub 2}) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO{sub 2} and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film to form the lipase/nano-CeO{sub 2}/TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO{sub 2}/TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film and hence the lipase/nano-CeO{sub 2}/TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp

  2. Study on corrosion test techniques in lead bismuth eutectic flow. Joint research report in JFY2002

    International Nuclear Information System (INIS)

    cable electrode type and tubular electrode type were tested in the lead bismuth loop, and the performances were compared with each other. (author)

  3. Preferential growth and enhanced dielectric properties of Ba0.7Sr0.3TiO3 thin films with preannealed Pt bottom electrode

    International Nuclear Information System (INIS)

    Ba0.7Sr0.3TiO3 (BST) thin films, about 100 nm in thickness, were prepared on unannealed and 700 °C-preannealed Pt bottom electrodes by the ion beam sputtering and post-deposition annealing method. It was found that the preannealed Pt layer has a more compact structure, making it not only a bottom electrode but also a good template for high-quality BST thin film growth. The BST films deposited on preannealed Pt bottom electrodes showed (0 0 l)-preferred orientation, dense and uniform microstructure with no intermediate phase formed at the film/electrode interface, and thus enhanced dielectric properties. As a result, the typical relative dielectric constant and tunability (under a dc electric field of 1 MV cm−1) reach 180 and 50.1%, respectively, for the BST thin films with preannealed Pt bottom electrodes, which are significantly higher than those (166 and 41.3%, respectively) for the BST thin films deposited on unannealed Pt bottom electrodes. (paper)

  4. Micromorph thin-film silicon solar cells with transparent high-mobility hydrogenated indium oxide front electrodes

    Science.gov (United States)

    Battaglia, Corsin; Erni, Lukas; Boccard, Mathieu; Barraud, Loris; Escarré, Jordi; Söderström, Karin; Bugnon, Grégory; Billet, Adrian; Ding, Laura; Despeisse, Matthieu; Haug, Franz-Josef; Wolf, Stefaan De; Ballif, Christophe

    2011-06-01

    We investigate the performance of hydrogenated indium oxide as a transparent front electrode for micromorph thin-film silicon solar cells on glass. Light trapping is achieved by replicating the morphology of state-of-the-art zinc oxide electrodes, known for their outstanding light trapping properties, via ultraviolet nanoimprint lithography. As a result of the high electron mobility and excellent near-infrared transparency of hydrogenated indium oxide, the short-circuit current density of the cells is improved with respect to indium tin oxide and zinc oxide electrodes. We assess the potential for further current gains by identifying remaining sources of parasitic absorption and evaluate the light trapping capacity of each electrode. We further present a method, based on nonabsorbing insulating silicon nitride electrodes, allowing one to directly relate the optical reflectance to the external quantum efficiency. Our method provides a useful experimental tool to evaluate the light trapping potential of novel photonic nanostructures by a simple optical reflectance measurement, avoiding complications with electrical cell performance.

  5. Functionalization of indium-tin-oxide electrodes by laser-nanostructured gold thin films for biosensing applications

    Science.gov (United States)

    Grochowska, Katarzyna; Siuzdak, Katarzyna; Karczewski, Jakub; Śliwiński, Gerard

    2015-12-01

    The production and properties of the indium-tin-oxide (ITO) electrodes functionalized by Au nanoparticle (NP) arrays of a relatively large area formed by pulsed laser nanostructuring of thin gold films are reported and discussed. The SEM inspection of modified electrodes reveals the presence of the nearly spherical and disc-shaped particles of dimensions in the range of 40-120 nm. The NP-array geometry can be controlled by selection of the laser processing conditions. It is shown that particle size and packing density of the array are important factors which determine the electrode performance. In the case of NP-modified electrodes the peak current corresponding to the glucose direct oxidation process shows rise with increasing glucose concentration markedly higher comparing to the reference Au disc electrode. The detection limit reaches 12 μM and linear response of the sensor is observed from 0.1 to 47 mM that covers the normal physiological range of the blood sugar detection.

  6. Dechlorination of pentachlorophenol (PCP) in aqueous solution on novel Pd-loaded electrode modified with PPy-SDBS composite film.

    Science.gov (United States)

    Sun, Zhirong; Wei, Xuefeng; Zhang, Huan; Hu, Xiang

    2015-03-01

    Pentachlorophenol (PCP) is a persistent pollutant and a suspected human carcinogen. It can be found in the air, water, and soil and enters the environment through evaporation from treated wood surfaces, industrial spills, and disposal at uncontrolled hazardous waste sites. Ecotoxicity of PCP necessitates the development of rapid and reliable remediation techniques. Electrocatalytic hydrogenolysis (ECH) has been proven as a promising method for detoxification of halogenated wastes, due to its rapid reaction rate, low apparatus cost, mild reaction conditions, and absence of secondary contaminants. Challenge for the application of ECH is to prepare a Pd-coated cathode with high stability, high catalytic activity, and low Pd loading level. In this work, Pd/polypyrrole-sodium dodecyl benzene sulfonate/meshed Ti (Pd/PPy-SDBS/Ti) electrode was prepared and was characterized by cyclic voltammetry, scanning electron microscopy, X-ray diffraction, and inductively coupled plasma-atomic emission spectrometry. Electrochemically reductive dechlorination of PCP on the Pd/PPy-SDBS/Ti electrode in aqueous solution was investigated. Pd microparticles were uniformly dispersed on PPy-SDBS film which was previously electrodeposited on the meshed Ti supporting electrode. The loading of Pd on the electrode was 0.72 mg cm(-2). Electrocatalytic dechlorination of PCP was performed in a two-compartment cell separated by cation-exchange membrane. The PCP removal on the Pd/PPy-SDBS/Ti electrode could reach 100 % within 70 min with dechlorination current 3 mA when PCP initial concentration was 10 mg L(-1) and initial pH was 2.4. Conversion of PCP on the Pd/PPy-SDBS/Ti electrode followed pseudo-first-order kinetics, and the apparent activation energy was 13.0 kJ mol(-1). The removal of PCP still kept 100 % after 70 min dechlorination when the Pd/PPy-SDBS/Ti cathode was reused ten times. The electrode exhibited promising dechlorination potential with high electrocatalytic activity, good stability

  7. Bottom electrodes dependence of microstructures and dielectric properties of compositionally graded (Ba1-xSrx)TiO3 thin films

    International Nuclear Information System (INIS)

    Compositionally graded (Ba1-xSrx)TiO3 (BST) thin films, with x decreasing from 0.3 to 0, were deposited on Pt/Ti/SiO2/Si and Ru/SiO2/Si substrates by radio frequency magnetron sputtering technology. The microstructure and dielectric properties of the graded BST thin films were investigated. It was found that the films on Ru electrode have better crystallization, and that RuO2 is present between the Ru bottom electrode and the graded BST thin films by X-ray diffraction and SEM analysis. Dielectric measurement reveals that the graded BST thin films deposited on Ru bottom electrode have higher dielectric constant and tunability. The enhanced dielectric behavior is attributed to better crystallization as well as smaller space charge capacitance width and the formation of RuO2 that is more compatible with the BST films. The graded BST films on Ru electrode show higher leakage current due to lower barrier height and rougher surface of bottom electrode

  8. Comparison of lead zirconate titanate thin films for microelectromechanical energy harvester with interdigitated and parallel plate electrodes.

    Science.gov (United States)

    Chidambaram, Nachiappan; Mazzalai, Andrea; Balma, Davide; Muralt, Paul

    2013-08-01

    Lead zirconate titanate (PZT) thin films on insulator- buffered silicon substrates with interdigitated electrodes (IDEs) have the potential to harvest more energy than parallel plate electrode (PPE) structures because the former exploit the longitudinal piezoelectric effect, which is about twice as high as the transverse piezoelectric effect used by PPE structures. In this work, both options are compared with respect to dielectric, ferroelectric, and piezoelectric properties, leakage currents, and figure of merit (FOM) for energy harvesting. The test samples were silicon beams with {100} PZT thin films in the case of the PPE geometry, and random PZT thin films for the IDE geometry. Both films were obtained by an identical sol-gel route. Almost the same dielectric constants were derived when the conformal mapping method was applied for the IDE capacitor to correct for the IDE geometry. The dielectric loss was smaller in the IDE case. The ferroelectric loops showed a higher saturation polarization, a higher coercive field, and less back-switching for the IDE case. The leakage current density of the IDE structure was measured to be about 4 orders of magnitude lower than that of the PPE structure. The best FOM of the IDE structures was 20% superior to that of the PPE structures while also having a voltage response that was ten times higher (12.9 mV/μ strain). PMID:25004526

  9. Wet-Chemical Surface Texturing of Sputter-Deposited ZnO:Al Films as Front Electrode for Thin-Film Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Xia Yan

    2015-01-01

    Full Text Available Transparent conductive oxides (TCOs play a major role as the front electrodes of thin-film silicon (Si solar cells, as they can provide optical scattering and hence improved photon absorption inside the devices. In this paper we report on the surface texturing of aluminium-doped zinc oxide (ZnO:Al or AZO films for improved light trapping in thin-film Si solar cells. The AZO films are deposited onto soda-lime glass sheets via pulsed DC magnetron sputtering. Several promising AZO texturing methods are investigated using diluted hydrochloric (HCl and hydrofluoric acid (HF, through a two-step etching process. The developed texturing procedure combines the advantages of the HCl-induced craters and the smaller and jagged—but laterally more uniform—features created by HF etching. In the two-step process, the second etching step further enhances the optical haze, while simultaneously improving the uniformity of the texture features created by the HCl etch. The resulting AZO films show large haze values of above 40%, good scattering into large angles, and a surface angle distribution that is centred at around 30°, which is known from the literature to provide efficient light trapping for thin-film Si solar cells.

  10. Preparation of Li4Ti5O12 electrode thin films by a mist CVD process with aqueous precursor solution

    Directory of Open Access Journals (Sweden)

    Kiyoharu Tadanaga

    2015-03-01

    Full Text Available Spinel Li4Ti5O12 thin films were prepared by a mist CVD process, using an aqueous solution of lithium nitrate and a water-soluble titanium lactate complex as the source of Li and Ti, respectively. In this process, mist particles ultrasonically atomized from a source aqueous solution were transferred by nitrogen gas to a heating substrate to prepare thin films. Scanning electron microscopy observation showed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 500 nm were obtained. In the X-ray diffraction analysis, formation of Li4Ti5O12 spinel phase was confirmed in the obtained thin film sintered at 700 °C for 4 h. The cell with the thin films as an electrode exhibited a capacity of about 110 mAh g−1, and the cell showed good cycling performance during 10 cycles.

  11. Development of conductive coated polyester film as RPC electrodes using screen printing

    International Nuclear Information System (INIS)

    Each of the three 16 kton ICAL detector modules at the India-based Neutrino Observatory (INO) will use RPCs as the active element, sandwiched between 6 cm thick soft iron plates, for measurements on atmospheric neutrinos. The electrodes of the RPC are float glass sheets having a volume resistivity of about 1012-1013 Ω cm (at room temperature) covered with carbon/graphite or a conductive paint with a surface resistivity of ∼800 kΩ/square to 1 MΩ/square to apply high voltage on the glass surface, so that this surface does not shield the discharge signal from the external pickup plates and is small compared to the resistivity of the glass to provide a uniform potential across the entire surface. We initially coated the surface with locally available graphite powder, mixed with lacquer and thinner, and were able to get a few hundred kΩ/square resistivity. However, we observed a drastic reduction in surface resistivity with time and it came unstuck from the glass. Subsequently a conductive paint developed by Kansai-Nerolac was used. This paint uses modified acrylic resin as binder, conductive black pigment and solvents, which include aromatic hydrocarbons and alcohols. At room temperature, the surface dries in 10 minutes, while complete drying takes ∼18 hours. The spraying is done at a pressure of 4 kg/cm2 with the glass plate kept at a distance of 8-10 in. Using this paint, we are able to achieve the required resistance of ∼ few hundred kΩ/square. We still need to study the long term stability and best curing method. We need to automate the procedure to get a uniform coat and to coat a large number of glasses for the final detector. While robotic systems are available abroad costing about 5 000 000 rupees, we are exploring other alternatives. In particular, we are in the process of developing a polyester film, with a conductive coating on one side, which can be glued on to the glass. The coating was done using on a local commercial screen printing machine

  12. Fabrication and characterization of implantable and flexible nerve cuff electrodes with Pt, Ir and IrOx films deposited by RF sputtering

    Science.gov (United States)

    Lee, Soo Hyun; Jung, Jung Hwan; Chae, Youn Mee; Suh, Jun-Kyo Francis; Kang, Ji Yoon

    2010-03-01

    This paper presents the fabrication and characterization of implantable and flexible nerve cuff electrodes for neural interfaces using the conventional BioMEMS technique. In order to fabricate a flexible nerve electrode, polyimide (PI) was chosen as the substrate material. Then, nerve electrodes were thermally re-formed in a cuff shape so as to increase the area in which the charges were transferred to the nerve. Platinum (Pt), iridium (Ir) and iridium oxide (IrOx) films, which were to serve as conducting materials for the nerve electrodes, were deposited at different working pressures by RF magnetron sputtering. The electrochemical properties of the deposited films were characterized by electrochemical impedance spectroscopy (EIS). The charge delivery capacities of the films were recorded and calculated by cyclic voltammetry (CV). The deposited films of Pt, Ir and IrOx have strong differences in electrochemical properties, which depend on the working pressure of sputter. Each film deposited at 30 mTorr of working pressure shows the highest value of charge delivery capacity (CDC). For the IrOx films, the electrochemical properties were strongly affected by the working pressure as well as the Ar:O2 gas ratio. The IrOx film deposited with an Ar:O2 gas ratio of 8:1 showed the highest CDC of 59.5 mC cm-2, which was about five times higher than that of films deposited with a 1:1 gas ratio.

  13. Large-scale patterned multi-layer graphene films as transparent conducting electrodes for GaN light-emitting diodes.

    Science.gov (United States)

    Jo, Gunho; Choe, Minhyeok; Cho, Chu-Young; Kim, Jin Ho; Park, Woojin; Lee, Sangchul; Hong, Woong-Ki; Kim, Tae-Wook; Park, Seong-Ju; Hong, Byung Hee; Kahng, Yung Ho; Lee, Takhee

    2010-04-30

    This work demonstrates a large-scale batch fabrication of GaN light-emitting diodes (LEDs) with patterned multi-layer graphene (MLG) as transparent conducting electrodes. MLG films were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized MLG film properties, possessing a sheet resistance of [Formula: see text] with a transparency of more than 85% in the 400-800 nm wavelength range. The MLG was applied as the transparent conducting electrodes of GaN-based blue LEDs, and the light output performance was compared to that of conventional GaN LEDs with indium tin oxide electrodes. Our results present a potential development toward future practical application of graphene electrodes in optoelectronic devices. PMID:20368676

  14. Large-scale patterned multi-layer graphene films as transparent conducting electrodes for GaN light-emitting diodes

    International Nuclear Information System (INIS)

    This work demonstrates a large-scale batch fabrication of GaN light-emitting diodes (LEDs) with patterned multi-layer graphene (MLG) as transparent conducting electrodes. MLG films were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized MLG film properties, possessing a sheet resistance of ∼620 Ω/□ with a transparency of more than 85% in the 400-800 nm wavelength range. The MLG was applied as the transparent conducting electrodes of GaN-based blue LEDs, and the light output performance was compared to that of conventional GaN LEDs with indium tin oxide electrodes. Our results present a potential development toward future practical application of graphene electrodes in optoelectronic devices.

  15. Analytical modeling and simulation of electrochemical charge/discharge behavior of Si thin film negative electrodes in Li-ion cells

    Science.gov (United States)

    Jagannathan, M.; Chandran, K. S. Ravi

    2014-02-01

    Physically-based analytical models that provide insights into the diffusion and/or interface charge transfer effects in bulk (lithiating/delithiating) electrodes are needed to truly assess the performance/limitations of electrode materials for Li-ion batteries. In this context, an analytical modeling framework is constructed here to predict the electrochemical charge-discharge characteristics during lithiation and delithiation of solid amorphous Si (a-Si) thin film electrodes. The framework includes analytical expressions that satisfy Fick's second law for Li transport and the requisite flux boundary conditions of lithiation and delithiation steps. The expressions are derived here by the method of separation of variables. They enable the determination of transient Li concentration profiles in the thin film electrode as a function of state of charge/discharge. The time-dependent electrode surface concentrations (at the electrode-electrolyte interface) obtained from these profiles were used to determine the activation overpotentials and thus, the non-equilibrium cell potentials, as a function of state of charge/discharge using Butler-Volmer kinetics. The simulated charge/discharge characteristics agreed well with the experimental data of a-Si thin film electrodes obtained at different C-rates. The model offers insights into how the charge-discharge behavior is controlled by diffusion limitation within electrode and/or the activation overpotentials at the interface. The analytical framework is also shown to predict successfully the hysteretic behavior of lithiation/delithiation voltage curves.

  16. The effect on performance of fabrication parameter variations of thick-film screen printed silver/silver chloride potentiometric reference electrodes

    OpenAIRE

    Sophocleous, Marios; Glanc, Monika; Atkinson, John; Garcia-Breijo, Eduardo

    2013-01-01

    Thick-film screen printed silver-silver chloride (Ag/AgCl) reference electrodes have been fabricated and investigated as an alternative to liquid electrolyte Ag/AgCl reference electrodes. The performance of the electrodes was examined with variations of the potassium chloride (KCl) concentration in the final (top) layer of the electrode. Also, different types of binder (glass and polymer) were tested for the underlying Ag/AgCl layer. The addition of another layer on top of the KCl containing ...

  17. Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

    Science.gov (United States)

    Gallay, P.; Tosi, E.; Madrid, R.; Tirado, M.; Comedi, D.

    2016-10-01

    We present a glucose biosensor based on ZnO nanowire self-sustained films grown on compacted graphite flakes by the vapor transport method. Nanowire/graphite films were fragmented in water, filtered to form a colloidal suspension, subsequently functionalized with glucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices were evaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical responses of the devices were determined in buffer solutions with successive glucose aggregates using a tripolar electrode system. The nanostructured biosensors showed excellent analytical performance, with linear response to glucose concentrations, high sensitivity of up to ≈17 μA cm-2 mM-1 in the 0.03-1.52 mM glucose concentration range, relatively low Michaelis-Menten constant, excellent reproducibility and a fast response. The detection limits are more than an order of magnitude lower than those achievable in commercial biosensors for glucose control, which is promising for the development of glucose monitoring methods that do not require blood extraction from potentially diabetic patients. The strong detection enhancements provided by the functionalized nanostructures are much larger than the electrode surface-area increase and are discussed in terms of the physical and chemical mechanisms involved in the detection and transduction processes.

  18. Electrochemical behaviour of metal hexacyanoferrate converted to metal hydroxide films immobilized on indium tin oxide electrodes-Catalytic ability towards alcohol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: In this work, we demonstrate a simple method to modify indium tin oxide (ITO) electrodes in order to perform electro-catalytic oxidation of alcohols in alkaline medium. Metal hexacyanoferrate (MHCF) films such as nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF) were successfully immobilized on ITO electrodes using an electrochemical method. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structural and morphological aspects of MHCF films. Cyclic voltammetry (CV) was used to study the redox properties and to determine the surface coverage of these films on ITO electrodes. Electrochemical potential cycling was carried out in alkaline medium in order to alter the chemical structure of these films and convert to their corresponding metal hydroxide films. SEM and XPS were performed to analyze the structure and morphology of metal hydroxide modified electrodes. Electro-catalytic oxidation ability of these films towards methanol and ethanol in alkaline medium was investigated using CV. From these studies we found that metal hydroxide modified electrodes show a better catalytic performance and good stability for methanol oxidation along with the alleviation of CO poisoning effect. We have obtained an anodic oxidation current density of ∼82 mA cm-2 for methanol oxidation, which is at least 10 fold higher than that of any metal hydroxide modified electrodes reported till date. The onset potential for methanol oxidation is lowered by ∼200 mV compared to other chemically modified electrodes reported. A plausible mechanism was proposed for the alcohol oxidation based on the redox properties of these modified electrodes. The methodology adapted in this work does not contain costlier noble metals like platinum and ruthenium and is economically viable.

  19. Bismuth toxicity in patients treated with bismuth iodoform paraffin packs.

    Science.gov (United States)

    Atwal, A; Cousin, G C S

    2016-01-01

    Bismuth is a heavy metal used in bismuth iodoform paraffin paste (BIPP) antiseptic dressings and in a number of other medical preparations. It can be absorbed systemically and cause toxicity. We report 2 cases of such neurotoxicity after it was used in operations on the jaws.

  20. Atmospheric Environment Fabrication of Composite Films by Ethanol Catalytic Combustion and Its Use as Counter Electrodes for Dye-Sensitized Soar Cells

    Directory of Open Access Journals (Sweden)

    Xiaoping Zou

    2014-01-01

    Full Text Available The composite films which consist of amorphous carbon, carbon nanotube, and iron nanoparticles were prepared by ethanol catalytic combustion in atmospheric environment. The as-prepared composite films have good electrocatalytic activity and high conductivity which is due to their particular structure. The efficiency of the composite films based dye-sensitized soar cells (DSSCs is closed to that of the Pt based one. Most importantly, the DSSC employing the composite films presents a higher FF than those of Pt based solar cell. In addition, it is a simple method for mass production of composite films counter electrode (CE which is expected to reduce the cost of fabricating DSSCs.

  1. Amperometric bienzyme glucose biosensor based on carbon nanotube modified electrode with electropolymerized poly(toluidine blue O) film

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wenju [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Wang Fang [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong (Hong Kong)] [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Yao Yanli [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Hu Shengshui [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Shiu, Kwok-Keung, E-mail: kkshiu@hkbu.edu.h [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2010-09-30

    The amperometric bienzyme glucose biosensor utilizing horseradish peroxidase (HRP) and glucose oxidase (GOx) immobilized in poly(toluidine blue O) (PTBO) film was constructed on multi-walled carbon nanotube (MWNT) modified glassy carbon electrode. The HRP layer could be used to analyze hydrogen peroxide with toluidine blue O (TBO) mediators, while the bienzyme system (HRP + GOx) could be utilized for glucose determination. Glucose underwent biocatalytic oxidation by GOx in the presence of oxygen to yield H{sub 2}O{sub 2} which was further reduced by HRP at the MWNT-modified electrode with TBO mediators. In the absence of oxygen, glucose oxidation proceeded with electron transfer between GOx and the electrode mediated by TBO moieties without H{sub 2}O{sub 2} production. The bienzyme electrode offered high sensitivity for amperometric determination of glucose at low potential, displaying Michaelis-Menten kinetics. The bienzyme glucose biosensor displayed linear response from 0.1 to 1.2 mM with a sensitivity of 113 mA M{sup -1} cm{sup -2} at an applied potential of -0.10 V in air-saturated electrolytes.

  2. A novel strategy to improve the sensitivity of antibiotics determination based on bioelectrocatalysis at molecularly imprinted polymer film electrodes.

    Science.gov (United States)

    Lian, Wenjing; Liu, Shuang; Wang, Lei; Liu, Hongyun

    2015-11-15

    A new strategy for the sensitive detection of kanamycin (KA) and other antibiotics based on molecularly imprinted polymer (MIP) and bioelectrocatalysis was developed in the present study. The KA-polypyrrole MIP films were electropolymerized on the surface of pyrolytic graphite (PG) electrodes, with pyrrole (PY) serving as the monomer and KA as the template. Because KA is electro-inactive, electroactive K3[Fe(CN)6] was used as the probe in the cyclic voltammetric (CV) measurements. The difference of the CV reduction peaks of K3[Fe(CN)6] at electrodes between the MIP films after KA removal and KA-rebinding MIP films could thus be used to determine KA quantitatively. When horseradish peroxidase (HRP) and H2O2 were added into the testing solution, the detection sensitivity of the system was greatly amplified because the electrochemical reduction of H2O2 could be catalyzed by HRP and mediated by K3[Fe(CN)6]. With the bioelectrocatalysis amplification, the limit of detection (LOD) for KA fell as low as 28 nM, approximately two orders of magnitude lower than that for the MIP films in the absence of enzymatic catalysis. The strategy demonstrated the generality. Not only KA but also other antibiotics, such as oxytetracycline (OTC), could be determined by this method. More significantly, in addition to the K3[Fe(CN)6]-HRP-H2O2 system, other bioelectrocatalysis systems, such as Fc(COOH)2-GOD-glucose (Fc(COOH)2=ferrocenedicarboxylic acid, GOD=glucose oxidase), could also be used to amplify the CV signal and realize the sensitive detection of KA for the MIP film system, thereby illustrating the great potential and prospects of the strategy. PMID:26079673

  3. Effects of high working pressure on dielectric properties of sputtered (Ba,Sr)TiO3 films on Ir electrodes

    International Nuclear Information System (INIS)

    High working pressure (47 mTorr) was used for rf-sputtered (Ba,Sr)TiO3 (BST) films on Ir bottom electrodes to enhance the in situ formation of IrO2 without postannealing. We verified that oxygen plasma bombardment on the Ir surface during the deposition of BST films was the dominant mechanism for in situ IrO2 formation under the condition of high working pressure. The as-deposited BST film of 100 nm grown at 500 deg. C shows a high dielectric constant of 630 (at 10 kHz); however, the leakage current is relatively large (6x10-5 A/cm2 at 100 kV/cm). The large leakage current results from the rough interface due to the formation of thick IrO2. To reduce leakage current, the double-layer technology was used, in which a thin BST film (5 nm) was first deposited with pure Ar, and followed by the deposition of a thick film (95 nm) with mixture gas (Ar/O2=1). The thin BST layer can significantly reduce the roughness of IrO2, resulting in lower leakage current (4x10-7 A/cm2); however, since the thin BST layer is oxygen deficient, the dielectric constant is reduced to 443

  4. Study of electrochemical properties of thin film materials obtained using plasma technologies for production of electrodes for pacemakers

    Science.gov (United States)

    Obrezkov, O. I.; Vinogradov, V. P.; Krauz, V. I.; Mozgrin, D. V.; Guseva, I. A.; Andreev, E. S.; Zverev, A. A.; Starostin, A. L.

    2016-09-01

    Studies of thin film materials (TFM) as coatings of tips of pacemaker electrodes implanted into the human heart have been performed. TFM coatings were deposited in vacuum by arc magnetron discharge plasma, by pulsed discharge of “Plasma Focus”, and by electron beam evaporation. Simulation of electric charge transfer to the heart in physiological blood- imitator solution and determination of electrochemical properties of the coatings were carried out. TFM of highly developed surface of contact with tissue was produced by argon plasma spraying of titanium powder with subsequent coating by titanium nitride in vacuum arc assisted by Ti ion implantation. The TFM coatings of pacemaker electrode have passed necessary clinical tests and were used in medical practice. They provide low voltage myocardium stimulation thresholds within the required operating time.

  5. Electrical conduction processes in as-deposited indium phthalocyanine chloride thin films using gold and aluminium electrode combination

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, Mammen; Menon, C S; Unnikrishnan, N V [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam-686 560, Kerala (India)

    2006-01-11

    Sandwich structures of the type (Au-InPcCl-Al) have been fabricated by successive vacuum deposition of indium phthalocyanine chloride (InPcCl) thin films and aluminium (Al) fingers onto Ohmic gold (Au) electrodes on glass substrates. Device characteristics of as-deposited Au/InPcCl/Al are obtained and found to show rectification properties. Current density-voltage characteristics under forward bias (aluminium electrode negative) are found to be due to Ohmic conduction at lower voltages. At higher voltages there is space charge limited conductivity (SCLC) controlled by an exponential trapping distribution above the valence edge. Transport properties of the material at ambient temperature have been obtained from the analysis of the samples in the Ohmic and SCLC regions. Under the reverse bias, Schottky emission is identified at lower voltages.

  6. Ascorbate electro-oxidation by modified electrodes: Polypyrrole and polypyrrole/Ni(OH){sub 2} composite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues da Silva, Marcelo [Faculdade de Engenharia/Colegio Tecnico Industrial, UNESP, CP 473, 17033-360 Bauru, SP (Brazil); Ferreira, Marcelo Silva [Departamento de Quimica, Centro de Ciencias Exatas, UEL, CP 6001, 86051-980 Londrina, PR (Brazil); Dall' Antonia, Luiz Henrique, E-mail: luizh@uel.br [Departamento de Quimica, Centro de Ciencias Exatas, UEL, CP 6001, 86051-980 Londrina, PR (Brazil)

    2012-08-01

    The present paper describes the utilization of polypyrrole and the composite of polypyrrole doped with nickel hydroxide modified electrodes toward the catalytic oxidation of ascorbate. Films were potentiostatically deposited onto a glassy carbon surface and Fluor-doped tin oxide glass for different times. The physical characterization was performed using the low angle X-ray diffraction technique. Furthermore, the films were electrochemically characterized using cyclic voltammetry. The X-ray diffraction results show the existence of different polymorphic phases of nickel hydroxide in the polymer matrix, and the {beta}-Ni(OH){sub 2} phase appears to be dominant. The cyclic voltammetry profile in KOH solution shows the presence of two redox peaks that are related to the Ni{sup II}/Ni{sup III} and Ni{sup III}/Ni{sup II} couples, at approximately 0.5 and 0.35 V, respectively. The reversible electro-oxidation of ascorbate was observed on the surface of the polypyrrole and composite films. The analytical curves obtained using voltammetric techniques show a linear relationship between the faradaic current and the increase of the ascorbic acid concentration. The sensitivity of these films, which is obtained from the slope of the analytical curves, shows that the composite film is more electroactive than the polypyrrole film: 133.4 mA L mol{sup -1} cm{sup -2} and 83.8 mA L mol{sup -1} cm{sup -2}, respectively. The rate constants of the catalytic ascorbate electro-oxidation were also reported, where the mean values were found to be 217.74 M{sup -1} s{sup -1} and 54.37 M{sup -1} s{sup -1}, for the composite and polypyrrole films, respectively. The low cost of polypyrrole doped with Ni(OH){sub 2} composite electrodes presents a more selective and high sensitivity to determine ascorbic acid concentration. - Highlights: Black-Right-Pointing-Pointer Electrochemical synthesis of polypyrrole and nickel hydroxide composite thin films Black-Right-Pointing-Pointer High sensitivity

  7. Influence of substrate temperature on structural and optical properties of bismuth oxide thin films deposited by close-spaced vacuum sublimation

    Science.gov (United States)

    Ivashchenko, M. M.; Buryk, I. P.; Latyshev, V. M.; Stepanenko, A. O.; Levchenko, K. S.

    2015-12-01

    Bi2O3 thin films were deposited on ultrasonically-cleaned glass and mica substrates by close-spaced vacuum sublimation technique. Films surface morphology was studied using scanning electron microscopy (SEM). Structural study based on the transmission-electron microscopy (TEM) and selected-area electron diffraction (SAED) analysis has been shown that deposited films were polycrystalline with face-centered cubic structure. Optical study was carried out by spectral photometry analysis in the wavelengths range λ = 320-900 nm using the optical transmittance and absorbance measurements. For determination optical band gap Eg the Tauc plot was used and the band gap energy Eg is determined in the range of 3.50-3.62 eV, respectively. Fourier-transform infra-red (FTIR) analysis shown that obtained films are well-crystalline and have a good optical quality.

  8. Highly (110)- and (111)-oriented BiFeO3 films on BaPbO3 electrode with Ru or Pt /Ru barrier layers

    Science.gov (United States)

    Lee, Chia-Ching; Wu, Jenn-Ming; Hsiung, Chang-Po

    2007-04-01

    Highly (110)- and (111)-oriented BiFeO3 (BFO) films were fabricated with BaPbO3 (BPO )/Ru and BPO /Pt/Ru as electrode/barrier on Si substrates by rf-magnetron sputtering. The BPO /Ru and BPO /Pt/Ru stacks both induce oriented BFO films and act as diffusion barriers. The (110)- and (111)-oriented BFO films possess excellent ferroelectric properties with only minor leakage. The values of remnant polarization are almost the same, about 42μC/cm2, for (110)- and (111)-oriented BFO films. However, polarization measured under varying pulse widths demonstrates that the switching polarization in (111)-oriented BFO films is higher than in (110)-oriented films. Additionally, (111)-oriented BFO films exhibit better retention properties than (110)-oriented films.

  9. Supported TiO2 film photocatalysis rection system with air(oxygen) electrode%含空气(氧)电极的负载型TiO2光催化反应体系

    Institute of Scientific and Technical Information of China (English)

    蔡乃才; 黄行九; 彭正合

    2000-01-01

      A novel photocatlysis reaction system is introduced, in which the air(oxygen) erectrode is used as counter electrode of supported TiO2 film electrode. When air(oxygen) electrode and TiO2 film electrode are in state of closed circuit by the Conductor, the rate of degradtion of the organic contaminant is apparently increased, for example, Under condition of same radiant intensity, after reaction for 3h, quantity of degradated oxalic acid in the solution is greater by about 46% than that in the absence of the air(oxygen) electrode. The function of the air(oxygen) electrode is discussed in the paper.

  10. Development of Novel Glucose and Pyruvate Biosensors at Poly(Neutral Red) Modified Carbon Film Electrodes. Application to Natural Samples

    OpenAIRE

    Ghica, Mariana Emilia; Brett, Christopher M. A.

    2006-01-01

    Amperometric biosensors based on the corresponding oxidase enzyme with poly(neutral red) redox mediator have been developed for the determination of glucose and pyruvate. The enzymes have been immobilized on top of poly(neutral red) modified carbon film electrodes with glutaraldehyde as the cross-linking agent. The biosensors were characterized by cyclic voltammetry and by electrochemical impedance spectroscopy. The glucose biosensor exhibited a linear response in the range 90 muM to 1.8 mM w...

  11. Impact of glycerol on zinc-oxide-based thin film transistors with indium molybdenum oxide transparent electrodes

    Science.gov (United States)

    MÄ dzik, Mateusz; Elamurugu, Elangovan; Flores, Raquel; Viegas, Jaime

    2016-02-01

    We report the fabrication of thin film transistors with ZnO channel and indium molybdenum oxide electrodes by sputtering. The fabricated transistors were then exposed to glycerol. We observe a temporary change in device performance after immersion of the FET in glycerol. Control structures without channel material are also used for demonstrating that the effect of saturation current increase is not due to glycerol alone as sugar alcohol is a low conductive medium. Various electrical and optical parameters are extracted. The presented results are useful for further integration of photonics and electronics in sensing applications

  12. Determination of Soil Base—Soluble Se by Anodic Stripping Voltammetry with Aurum Thin—Film Electrode

    Institute of Scientific and Technical Information of China (English)

    YANGZENG; HEYING; 等

    1994-01-01

    Determination of soil Se by anodic stripping voltammetry(ASV) with aurum thin-film electrode(ATFE)overcomes the interference of gold peak with selenium peak,and thus has a higher sensitivity with the miniumum detectable concentration being 0.017μg/mL,the standard deviation of the measured results leww than 0.012μg/g,the coefficient of variation lwoer than 10% ,and the recovery rate between 86% to 103%.Besides the measurement conditions,the digestion of soil sample was also studied in detail.

  13. Enhanced electrochemical activity of redox-labels in multi-layered protein films on indium tin oxide nanoparticle-based electrode

    International Nuclear Information System (INIS)

    Facile electrical communication between redox-active labeling molecules and electrode is essential in the electrochemical detection of bio-affinity reactions. In this report, nanometer-sized indium tin oxide (ITO) particles were employed in the fabrication of porous thick film electrodes to enhance the otherwise impeded electrochemical activity of redox labels in multi-layered protein films, and to enable quantitative detection of avidin/biotin binding interaction. To carry out the affinity reaction, avidin immobilized on an ITO electrode was reacted with mouse IgG labeled with both biotin and ruthenium Tris-(2,2'-bipyridine) (Ru-bipy). The binding reaction between avidin and biotin was detected by the catalytic voltammetry of Ru-bipy in an oxalate-containing electrolyte. On sputtered ITO thin film electrode, although a single layer of Ru-bipy labeled avidin exhibited substantial anodic current, attaching the label to the outer IgG layer of the avidin/biotin-IgG binding pair resulted in almost complete loss of the signal. However, electrochemical current was recovered on ITO film electrodes prepared from nanometer-sized particles. The surface of the nanoparticle structured electrode was found by scanning electron microscopy to be very porous, and had twice as much surface binding capacity for avidin as the sputtered electrode. The results were rationalized by the assumption of different packing density of avidin inner layer on the two surfaces, and consequently different electron transfer distance between the electrode and Ru-bipy on the IgG outer layer. A linear relationship between electrochemical current and IgG concentration was obtained in the range of 40-4000 nmol L-1 on the nanoparticle-based electrode. The approach can be employed in the electrochemical detection of immunoassays using non-enzymatic redox labels

  14. Microwave-assisted low temperature fabrication of ZnO thin film electrodes for solar energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Nirmal Peiris, T.A.; Sagu, Jagdeep S.; Hazim Yusof, Y.; Upul Wijayantha, K.G., E-mail: U.Wijayantha@lboro.ac.uk

    2015-09-01

    Metallic Zn thin films were electrodeposited on fluorine-doped tin oxide (FTO) glass substrates and oxidized under air by conventional radiant and microwave post-annealing methods to obtain ZnO thin film electrodes. The temperature of each post-annealing method was varied systematically and the photoelectrochemical (PEC) performance of electrodes was evaluated. The best photocurrent density achieved by the conventional radiant annealing method at 425 °C for 15 min was 93 μA cm{sup −2} at 1.23 V vs. NHE and the electrode showed an incident photon-to-electron conversion efficiency (IPCE) of 28.2%. X-ray diffractogram of this electrode showed that the oxidation of Zn to ZnO was not completed during the radiant annealing process as evident by the presence of metallic Zn in the electrode. For the electrode oxidized from Zn to ZnO under microwave irradiation, a photocurrent of 130 μA cm{sup −2} at 1.23 V vs. NHE and IPCE of 35.6% was observed after annealing for just 3 min, during which the temperature reached 250 °C. The photocurrent was 40% higher for the microwave annealed sample; this increase was attributed to higher surface area by preserving the nanostructure, confirmed by SEM surface topographical analysis, and better conversion yields to crystalline ZnO. Overall, it was demonstrated that oxidation of Zn to ZnO can be accomplished by microwave annealing five times faster than that of conventional annealing, thus resulting in a ~ 75% power saving. This study shows that microwave processing of materials offers significant economic and performance advantages for industrial scale up. - Highlights: • Conversion of Zn to ZnO by microwave and radiant annealing was conducted. • Microwave conversion was 5 times faster compared to radiant annealing. • Photoelectrochemical performance of microwave annealed ZnO was 40% higher. • Microwave annealing results in a 75% energy saving.

  15. Electrocatalytic oxidation behavior of L-cysteine at Pt microparticles modified nanofibrous polyaniline film electrode

    Institute of Scientific and Technical Information of China (English)

    MA Song-jiang; LUO Sheng-lian; ZHOU Hai-hui; KUANG Ya-fei; NING Xiao-hui

    2008-01-01

    Platinum(Pt)/nanofibrous polyaniline(PANI) electrode was prepared by pulse galvanostatic method and characterized by scanning electron microscopy. The electrochemical behavior of L-cysteine at the Pt/nanofibrous PANI electrode was investigated by cyclic voltammetry. The results indicate that the pH value of the solution and the Pt loading of the electrode have great effect on the electrocatalytic property of the Pt/nanofibrous PANI electrode; the suitable Pt loading of the electrode is 600 μg/cm2 and the suitable pH value of the solution is 4.5 for investigating L-cysteine oxidation. The L-cysteine sensor based on the Pt/nanofibrous PANI electrode has a good selectivity, reproducibility and stability. The Pt/nanofibrous PANI electrode is highly sensitive to L-cysteine, and the linear calibration curve for the oxidation of L-cysteine can be observed in the range of 0.2-5.0 mmol/L.

  16. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study.

    Science.gov (United States)

    Sapsanis, Christos; Omran, Hesham; Chernikova, Valeriya; Shekhah, Osama; Belmabkhout, Youssef; Buttner, Ulrich; Eddaoudi, Mohamed; Salama, Khaled N

    2015-01-01

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance. PMID:26213943

  17. Direct Electrochemistry of Cytochrome c on EDTA-ZrO2 Organic-inorganic Hybrid Film Modified Electrodes

    Institute of Scientific and Technical Information of China (English)

    徐静娟; 彭影; 刘守清; 陈洪渊

    2004-01-01

    A composite film of ethylenediamine tetraacetic acid (EDTA)-ZrO2 organic-inorganic hybrid was prepared based on the chelation between Zr(Ⅳ) and EDTA. The direct electrochemical behavior of cytochrome c (cyt. c) at the hybrid film modified glassy carbon electrodes was investigated. The immobilized EDTA can promote the redox of heme in horse heart cyt. c which gives rise to a pair of reversible redox peaks with a formal potential of 40 mV (vs. SCE). The peak current increased linearly with the increase of cyt. c concentration in the range of 1.6 × 10-6_the electron transfer of cyt. c. The impediment capability of metal ions depends on their coordination capability with EDTA and their valence number.

  18. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

    KAUST Repository

    Sapsanis, Christos

    2015-07-24

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

  19. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

    Directory of Open Access Journals (Sweden)

    Christos Sapsanis

    2015-07-01

    Full Text Available A prototypical metal-organic framework (MOF, a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc ligands (Cu(bdc·xH2O, was grown successfully as a thin film on interdigitated electrodes (IDEs. IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs. Accordingly, the resultant IDEs coated with the Cu(bdc·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

  20. Glass-like carbon, pyrolytic graphite or nanostructured carbon for electrochemical sensing of bismuth ion?

    Directory of Open Access Journals (Sweden)

    Jadranka Milikić

    2016-06-01

    Full Text Available Different carbon electrodes were explored for application in electroanalysis, namely for sensing of bismuth ion as model analyte. Carbon materials tested included glassy carbon, basal and edge plane pyrolytic graphite, as well as nanostructured carbonized polyaniline prepared in the presence of 3,5-dinitrosalicylic acid. Bismuth ion was chosen as model analyte as protocol for its detection and quantifications is still to be determined. Herein, anodic stripping voltammetry was used with study of effect of several parameters such as scan rate and deposition time. Electrode based on carbonized polyaniline showed the highest activity for bismuth ion sensing in terms of the highest current densities recorded both in a laboratory and in real sample, while basal plane pyrolytic graphite electrode gave the lowest limit of detection.

  1. The potential and challenges of thin-film electrolyte and nanostructured electrode for yttria-stabilized zirconia-base anode-supported solid oxide fuel cells

    Science.gov (United States)

    Noh, Ho-Sung; Yoon, Kyung Joong; Kim, Byung-Kook; Je, Hae-June; Lee, Hae-Weon; Lee, Jong-Ho; Son, Ji-Won

    2014-02-01

    Thin-film electrolytes and nanostructured electrodes are essential components for lowering the operation temperature of solid oxide fuel cells (SOFCs); however, reliably implementing thin-film electrolytes and nano-structure electrodes over a realistic SOFC platform, such as a porous anode-support, has been extremely difficult. If these components can be created reliably and reproducibly on porous substrates as anode supports, a more precise assessment of their impact on realistic SOFCs would be possible. In this work, structurally sound thin-film and nano-structured SOFC components consisting of a nano-composite NiO-yttria-stabilized zirconia (YSZ) anode interlayer, a thin YSZ and gadolinia-doped ceria (GDC) bi-layer electrolyte, and a nano-structure lanthanum strontium cobaltite (LSC)-base cathode, are sequentially fabricated on a porous NiO-YSZ anode support using thin-film technology. Using an optimized cell testing setup makes possible a more exact investigation of the potential and challenges of thin-film electrolyte and nanostructured electrode-based anode-supported SOFCs. Peak power densities obtained at 500 °C surpass 500 mW cm-2, which is an unprecedented low-temperature performance for the YSZ-based anode-supported SOFC. It is found that this critical, low-temperature performance for the anode-supported SOFC depends more on the electrode performance than the resistance of the thin-film electrolyte during lower temperature operation.

  2. Hydrogen peroxide biosensor based on electrodeposition of zinc oxide nanoflowers onto carbon nanotubes film electrode

    Institute of Scientific and Technical Information of China (English)

    Hui Ping Bai; Xu Xiao Lu; Guang Ming Yang; Yun Hui Yang

    2008-01-01

    A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes (MWNTs) firm. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy (SEM), and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9 × 10(-7) to 2.9 × 10(-3) mol/L with a correlation coefficient of 0.991, and response time <5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.

  3. Direct electrochemistry of glucose oxidase on the hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing

    Institute of Scientific and Technical Information of China (English)

    MA RongNa; WANG Bin; LIU Yan; LI Jing; ZHAO Qian; WANG GuoTao; JIA WenLi; WANG HuaiSheng

    2009-01-01

    A novel glucose biosensor was constructed by immobilizing the glucose oxidase (GOD) on a hydroxyapatite (Hap)/Nafion composite film modified glassy carbon electrode (GCE) and applied to the highly selective and sensitive determination of glucose.With the cooperation of Hap and Nation,the composite film played an important role in enhancing the stability and sensitivity of the biosensor.The results demonstrate that the GOD adsorbed onto the Hap/Nation composite film exhibits a pair of welldefined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen.On the basis of the decrease of the reduction current of dissolved oxygen at the applied potential of-0.80 V (vs.SCE) upon the addition of glucose,the concentration of glucose could be detected sensitively and selectively.The decreased reduction current was linear with the concentration of glucose in the range of 0.12-2.16 mM.The detection limit and sensitivity were 0.02 mM (S/N=3) and 6.75 mA·M~(-1),respectively.All the results demonstrate that Hap/Nafion composite film provides a novel and efficient platform for the immobilization of enzymes end realizes the direct electrochemistry.The composite materials should have potential applications in the fabrication of third-generation biosensors.

  4. Direct electrochemistry of glucose oxidase on the hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A novel glucose biosensor was constructed by immobilizing the glucose oxidase(GOD) on a hydroxyapatite(HAp)/Nafion composite film modified glassy carbon electrode(GCE) and applied to the highly selective and sensitive determination of glucose.With the cooperation of HAp and Nafion,the composite film played an important role in enhancing the stability and sensitivity of the biosensor.The results demonstrate that the GOD adsorbed onto the HAp/Nafion composite film exhibits a pair of welldefined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen.On the basis of the decrease of the reduction current of dissolved oxygen at the applied potential of -0.80 V(vs.SCE) upon the addition of glucose,the concentration of glucose could be detected sensitively and selectively.The decreased reduction current was linear with the concentration of glucose in the range of 0.12―2.16 mM.The detection limit and sensitivity were 0.02 mM(S/N=3) and 6.75 mA·M-1,respectively.All the results demonstrate that HAp/Nafion composite film provides a novel and efficient platform for the immobilization of enzymes and realizes the direct electrochemistry.The composite materials should have potential applications in the fabrication of third-generation biosensors.

  5. Magnetron sputtered AZO thin films on commercial ITO glass for application of a very low resistance transparent electrode

    International Nuclear Information System (INIS)

    In this paper, we report a coating method of reducing the sheet resistance of commercial Sn-doped In2O3 (ITO) glass by DC magnetron sputtering, without reducing its optical transmittance in the visible range of spectra. Aluminium oxide doped zinc oxide (AZO) films deposited on ITO glass showed highly (002)-oriented textured structure. An experimental procedure was designed to minimize the sheet resistance of AZO/ITO films in the deposition parameter space (mainly deposition temperature). Resistivity measurements showed that the ITO films with AZO coated under optimized deposition conditions showed a significant 81.4% decrease of sheet resistance when compared with those formed without AZO. Room temperature Hall effect measurements showed that the Hall mobility of the combined layers was greatly increased compared with that for single layer ITO. A high quality transparent electrode, having a resistance as low as 4.13 Ω/square and a high optical transmittance of 80% in the visible spectral range (with substrate), was obtained. The bilayer AZO/ITO film glass may be a good alternative substrate to ITO glass for advanced electro-optic applications

  6. Synthesis, structure and electrochemical properties of novel Li-Co-Mn-O epitaxial thin-film electrode using layer-by-layer deposition process

    Science.gov (United States)

    Lim, Jaemin; Lee, Soyeon; Suzuki, Kota; Kim, KyungSu; Kim, Sangryun; Taminato, Sou; Hirayama, Masaaki; Oshima, Yoshifumi; Takayanagi, Kunio; Kanno, Ryoji

    2015-04-01

    A novel epitaxial thin-film electrode for lithium batteries, with a composition of Li0.92Co0.65Mn1.35O4 and a cubic spinel structure, is fabricated on a SrTiO3(111) single-crystal substrate. Fabrication is carried out by layer-by-layer pulsed laser deposition of LiCoO2 with a layered rock-salt structure and LiMn2O4 with a spinel structure. The electrode is found to exhibit unique disordering of the lithium (8a) and transition-metal (16d) sites, leading to a higher rate capability and cycle retention ratio than those for a thin-film electrode with the same composition prepared by a conventional single-step deposition process. The proposed layer-by-layer deposition method allows an expanded range of compositional and structural variations for lithium battery electrode materials.

  7. Amorphous MoSx thin-film-coated carbon fiber paper as a 3D electrode for long cycle life symmetric supercapacitors

    Science.gov (United States)

    Balasingam, Suresh Kannan; Thirumurugan, Arun; Lee, Jae Sung; Jun, Yongseok

    2016-06-01

    Amorphous MoSx thin-film-coated carbon fiber paper as a binder-free 3D electrode was synthesized by a facile hydrothermal method. The maximum specific capacitance of a single electrode was 83.9 mF cm-2, while it was 41.9 mF cm-2 for the symmetric device. Up to 600% capacitance retention was observed for 4750 cycles.Amorphous MoSx thin-film-coated carbon fiber paper as a binder-free 3D electrode was synthesized by a facile hydrothermal method. The maximum specific capacitance of a single electrode was 83.9 mF cm-2, while it was 41.9 mF cm-2 for the symmetric device. Up to 600% capacitance retention was observed for 4750 cycles. Electronic supplementary information (ESI) available. See DOI: 10.1039/C6NR01200K

  8. Multilayer Films Electrodes Consisted of Cashew Gum and Polyaniline Assembled by the Layer-by-Layer Technique: Electrochemical Characterization and Its Use for Dopamine Determination

    Directory of Open Access Journals (Sweden)

    Sergio Bitencourt Araújo Barros

    2012-01-01

    with PANI or PANI-PA intercalated with CG or with PVS alternately resulting in four films with different sequences: PANI/CG PANI-PA/CG, PANI/PVS and PANI-PA/PVS, respectively. Analysis by cyclic voltammetry (CV of the films showed that the presence of gum increases the stability of the films in acidic medium. The performance of the modified electrode of PANI-PA/CG was evaluated in electro analytical determination of dopamine (DA. The tests showed great sensitivity of the film for this analyte that was detected at 10−5 mol L−1.

  9. Microscopy Study of Structural Evolution in Epitaxial LiCoO2 Positive Electrode Films during Electrochemical Cycling.

    Science.gov (United States)

    Tan, Haiyan; Takeuchi, Saya; Bharathi, K Kamala; Takeuchi, Ichiro; Bendersky, Leonid A

    2016-03-01

    The evolution of interface between the epitaxial thin film LiCoO2 (LCO) electrode and liquid electrolyte and inside the LCO film during electrochemical cycling has been analyzed by high resolution scanning transmission electron microscopy. Relaxation of sharp translational domain boundaries with mismatched layers of CoO2 octahedra occurs during cycling and results in formation of continuous CoO2 layers across the boundaries. The original trigonal layered structure of LiCoO2 tends to change into a spinel structure at the electrode/electrolyte interface after significant extraction of Li from LCO. This change is more pronounced at 4.2 V peak of CV, indicating lower stability of the layered LCO structure near its surface after Li is extracted above 60%. The transformed structure is identified to be close to Co3O4, with Co both on tetrahedral and octahedral sites, rather than to LiCo2O4 as it was suggested in earlier publications. Electron energy-loss spectroscopy measurements also show that Co ions oxidation state is reduced to mixed valence state Co(2+)/Co(3+) during the structure changes to spinel rather than oxidized. PMID:26911456

  10. Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

    Directory of Open Access Journals (Sweden)

    Q. Humayun

    2013-01-01

    Full Text Available ZnO thin films were deposited on patterned gold electrodes using the sol-gel spin coating technique. Conventional photolithography process was used to obtain the variable microgaps of 30 and 43 μm in butterfly topology by using zero-gap chrome mask. The structural, morphological, and electrical properties of the deposited thin films were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, and Keithley SourceMeter, respectively. The current-voltage (I-V characterization was performed to investigate the effect of UV light on the fabricated devices. The ZnO fabricated sensors showed a photo to dark current (Iph/Id ratios of 6.26 for 30 μm and 5.28 for 43 μm gap electrodes spacing, respectively. Dynamic responses of both fabricated sensors were observed till 1V with good reproducibility. At the applied voltage of 1 V, the response time was observed to be 4.817 s and 3.704 s while the recovery time was observed to be 0.3738 s and 0.2891 s for 30 and 43 μm gaps, respectively. The signal detection at low operating voltages suggested that the fabricated sensors could be used for miniaturized devices with low power consumption.

  11. Photoreactive and Metal-Platable Copolymer Inks for High-Throughput, Room-Temperature Printing of Flexible Metal Electrodes for Thin-Film Electronics.

    Science.gov (United States)

    Yu, You; Xiao, Xiang; Zhang, Yaokang; Li, Kan; Yan, Casey; Wei, Xiaoling; Chen, Lina; Zhen, Hongyu; Zhou, Hang; Zhang, Shengdong; Zheng, Zijian

    2016-06-01

    Photoreactive and metal-platable copolymer inks are reported for the first time to allow high-throughput printing of high-performance flexible electrodes at room temperature. This new copolymer ink accommodates various types of printing technologies, such as soft lithography molding, screen printing, and inkjet printing. Electronic devices including resistors, sensors, solar cells, and thin-film transistors fabricated with these printed electrodes show excellent electrical performance and mechanical flexibility. PMID:27074139

  12. Determination of 4-aminophenol using a glassy carbon electrode modified with a three-dimensionally ordered macroporous film of polycysteine

    International Nuclear Information System (INIS)

    A three-dimensionally ordered macroporous (3DOM) film of polycysteine (poly-Cys) was used to modify a glassy carbon electrode (GCE) to result in a sensor for 4-aminophenol. The new electrode was used to study the behavior of 4-aminophenol by cyclic voltammetry and differential pulse voltammetry. In comparison to a bare GCE and a GCE modified with poly-Cys without using template, this electrode displays a larger peak current which may be attributed to the structure of poly-Cys and the large surface area of the macroporous structure. The anodic peak current at a working voltage of 195 mV is linearly related to the concentration of 4-aminophenol in two concentration intervals: 0.02 to 20 μM and 20 to 200 μM, respectively. The detection limit is 8 nM (at an S/N ratio of 3). The method was successfully applied to the determination of 4-aminophenol in spiked water samples. (author)

  13. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Walker, Robert; Traulsen, Marie Lund;

    2015-01-01

    an applied potential.1-3 The presented work explores the polarisation induced changes in LSM electrode composition by utilizing in operando Raman spectroscopy and post mortem ToF-SIMS depth profiling on LSM thin film model electrodes fabricated by pulsed laser deposition on YSZ substrates with a thin (200 nm...... that were both reversible and dependent on the direction of the applied potential (Figure 1). The spectral changes were assigned to changes in the LSM electronic structure and specifically to changes in the relative oxide concentration in LSM’s near surface region. Ex situ ToF-SIMS depth profiles were...... and (b) +1 V. The peaks at 440 and 600 cm-1 are signatures from the CGO and YSZ electrolyte, respectively. Figure 2. ToF-SIMS depth profile of LSM electrode polarised at -1V at 700 °C for 2 h. Stapled lines mark layers enriched in different species. References 1 M. Backhaus-Ricoult, K. Adib, T. St...

  14. Determination of Antimony (III in Real Samples by Anodic Stripping Voltammetry Using a Mercury Film Screen-Printed Electrode

    Directory of Open Access Journals (Sweden)

    Olga Domínguez-Renedo

    2009-01-01

    Full Text Available This paper describes a procedure for the determination of antimony (III by differential pulse anodic stripping voltammetry using a mercury film screen-printed electrode as the working electrode. The procedure has been optimized using experimental design methodology. Under these conditions, in terms of Residual Standard Deviation (RSD, the repeatability (3.81 % and the reproducibility (5.07 % of the constructed electrodes were both analyzed. The detection limit for Sb (III was calculated at a value of 1.27×10–8 M. The linear range obtained was between 0.99 × 10–8 – 8.26 × 10–8 M. An analysis of possible effects due to the presence of foreign ions in the solution was performed and the procedure was successfully applied to the determination of antimony levels in pharmaceutical preparations and sea water samples.

  15. Synthesis and characterization of platinum thin film as top electrodes for multifunctional layer devices by PLD

    International Nuclear Information System (INIS)

    Platinum thin films were grown onto (001) oriented SrTiO3 substrates by means of the pulsed laser deposition technique. Structural and morphological characterizations were performed using XRD and AFM. The influence of substrate temperature and deposition rate was analyzed on the crystallographic properties of the film. As a result, an increment in the crystallinity of the film due to the change on the temperature was observed. On the other hand, Pt films showed a granular morphology and its roughness was related to the fluence and low deposition temperature. Finally their electrical properties were analyzed and discussed as a function of the previous morphological results.

  16. Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes

    Directory of Open Access Journals (Sweden)

    Cui Yan

    2014-01-01

    Full Text Available Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47O3 (PZT thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films.

  17. Working Electrodes

    Science.gov (United States)

    Komorsky-Lovrić, Šebojka

    In electrochemistry an electrode is an electronic conductor in contact with an ionic conductor. The electronic conductor can be a metal, or a semiconductor, or a mixed electronic and ionic conductor. The ionic conductor is usually an electrolyte solution; however, solid electrolytes and ionic melts can be used as well. The term "electrode" is also used in a technical sense, meaning the electronic conductor only. If not specified otherwise, this meaning of the term "electrode" is the subject of the present chapter. In the simplest case the electrode is a metallic conductor immersed in an electrolyte solution. At the surface of the electrode, dissolved electroactive ions change their charges by exchanging one or more electrons with the conductor. In this electrochemical reaction both the reduced and oxidized ions remain in solution, while the conductor is chemically inert and serves only as a source and sink of electrons. The technical term "electrode" usually also includes all mechanical parts supporting the conductor (e.g., a rotating disk electrode or a static mercury drop electrode). Furthermore, it includes all chemical and physical modifications of the conductor, or its surface (e.g., a mercury film electrode, an enzyme electrode, and a carbon paste electrode). However, this term does not cover the electrolyte solution and the ionic part of a double layer at the electrode/solution interface. Ion-selective electrodes, which are used in potentiometry, will not be considered in this chapter. Theoretical and practical aspects of electrodes are covered in various books and reviews [1-9].

  18. A novel and simple electrochemical sensor for electrocatalytic reduction of nitrite and oxidation of phenylhydrazine based on poly (o-anisidine) film using ionic liquid carbon paste electrode

    International Nuclear Information System (INIS)

    In this study, nitrite electroreduction and phenylhydrazine electrooxidation were investigated on poly(o-anisidine) formed by cyclic voltammetry at the surface of ionic liquid carbon paste electrode. The films were characterized by cyclic voltammetry and scanning electron microscopy (SEM) and were contrasted with poly(o-anisidine) prepared under identical conditions in the absence of ionic liquid in carbon paste electrode. This carbon paste modified electrode exhibits a good electrocatalytic capability (via an EC’ mechanism) for both electrooxidation and electroreduction of some important molecules. The obtained results showed that the catalytic oxidation peak currents of phenylhydrazine and catalytic reduction peak currents of nitrite at the surface of this simple (unfunctionalized) polymeric electrode were linearly dependent on their concentrations. Electrode was successfully applied for determination of nitrite and phenylhydrazine in real samples.

  19. Influence of molybdenum source/drain electrode contact resistance in amorphous zinc–tin-oxide (a-ZTO) thin film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Han, Dong-Suk; Kang, Yu-Jin; Park, Jae-Hyung [Department of Nanoscale Semiconductor Engineering, Hanyang University, 17 Haengdang-dong, Seoungdong-ku, Seoul 133-791 (Korea, Republic of); Jeon, Hyung-Tag [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seoungdong-ku, Seoul 133-791 (Korea, Republic of); Park, Jong-Wan, E-mail: jwpark@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seoungdong-ku, Seoul 133-791 (Korea, Republic of)

    2014-10-15

    Highlights: • We developed and investigated source/drain electrodes in oxide TFTs. • The Mo S/D electrodes showed good output characteristics. • Intrinsic TFT parameters were calculated by the transmission line method. - Abstract: This paper investigates the feasibility of a low-resistivity electrode material (Mo) for source/drain (S/D) electrodes in thin film transistors (TFTs). The effective resistances between Mo source/drain electrodes and amorphous zinc–tin-oxide (a-ZTO) thin film transistors were studied. Intrinsic TFT parameters were calculated by the transmission line method (TLM) using a series of TFTs with different channel lengths measured at a low source/drain voltage. The TFTs fabricated with Mo source/drain electrodes showed good transfer characteristics with a field-effect mobility of 10.23 cm{sup 2}/V s. In spite of slight current crowding effects, the Mo source/drain electrodes showed good output characteristics with a steep rise in the low drain-to-source voltage (V{sub DS}) region.

  20. Liquid crystalline phase synthesis of nanoporous MnO2 thin film arrays as an electrode material for electrochemical capacitors

    International Nuclear Information System (INIS)

    Graphical abstract: Three-dimensional (3D) MnO2 thin film arrays with nanoporous structure is electrodeposited on Ti foil from hexagonal lyotropic liquid crystalline phase. Low-angle X-ray diffraction (XRD), wide-angle XRD, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) are employed to study the morphology and the structure of the as-synthesized MnO2 materials. Galvanostatic charge/discharge measurements show the nanoporous, 3D electrode material exhibits excellent capacitive performance between the potential range of −0.1 to 0.9 V, and a maximum specific capacitance as high as 462 F g−1 are achieved in 0.5 M Na2SO4 solution at a charge/discharge current density of 4 A g−1. Highlights: ► 3D MnO2 thin film arrays with nanoporous structure is fabricated for the first time. ► A maximum specific capacitance as high as 462 F g−1 is obtained. ► The 3D and nanoporous superarchitecture facilitate electrolyte penetration. -- Abstract: Three-dimensional (3D) MnO2 thin film arrays with nanoporous structure is electrodeposited on Ti foil from hexagonal lyotropic liquid crystalline phase. Low-angle X-ray diffraction (XRD), wide-angle XRD, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) are employed to study the morphology and the structure of the as-synthesized MnO2 materials. Galvanostatic charge/discharge measurements show the nanoporous, 3D electrode material exhibits excellent capacitive performance between the potential range of −0.1 to 0.9 V, and a maximum specific capacitance as high as 462 F g−1 are achieved in 0.5 M Na2SO4 solution at a charge/discharge current density of 4 A g−1.

  1. All-organic polymer-dispersed liquid crystal light-valves integrated with electroactive anthraquinone-2-sulfonate-doped polypyrrole thin films as driving electrodes

    International Nuclear Information System (INIS)

    Highlights: → Fabrication of flexible semi-transparent all-polymer electrodes under ambient conditions without using a CVD system. → Characterization of the above electrodes based on anthraquinone-2-sulfonate-doped polypyrrole thin films. → Demonstration of all-organic liquid crystal light-valves with polypyrrole thin films as the driving electrodes. - Abstract: All-organic PDLC (polymer-dispersed liquid crystal) light-valves using all-polymer conductive substrates containing thin films of polypyrrole doped with anthraquinone-2-sulfonate (AQSA-) as the driving electrodes were fabricated in this study. The all-polymer conductive substrates were prepared under ambient conditions by in situ depositing polypyrrole thin films on blank flexible poly(ethylene terephthalate), or PET, substrates from aqueous media in which oxidative polymerization of pyrrole was taking place. The obtained flexible all-polymer conductive substrates were semi-transparent with cohesive coatings of AQSA-doped polypyrrole thin films (thickness ∼55 nm). The all-polymer flexible conductive substrates had sheet resistivity ∼40 kΩ □-1and T% transparency against air ∼78% at 600 nm. The light-valves fabricated using the above all-polymer conductive substrates showed ∼50% transparency against air at 600 nm when 4 V μm-1 electric field was applied.

  2. All-organic polymer-dispersed liquid crystal light-valves integrated with electroactive anthraquinone-2-sulfonate-doped polypyrrole thin films as driving electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Pen-Cheng, E-mail: wangpc@ess.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Yu, Jing-Yu; Li, Kuan-Hsun [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2011-11-01

    Highlights: {yields} Fabrication of flexible semi-transparent all-polymer electrodes under ambient conditions without using a CVD system. {yields} Characterization of the above electrodes based on anthraquinone-2-sulfonate-doped polypyrrole thin films. {yields} Demonstration of all-organic liquid crystal light-valves with polypyrrole thin films as the driving electrodes. - Abstract: All-organic PDLC (polymer-dispersed liquid crystal) light-valves using all-polymer conductive substrates containing thin films of polypyrrole doped with anthraquinone-2-sulfonate (AQSA{sup -}) as the driving electrodes were fabricated in this study. The all-polymer conductive substrates were prepared under ambient conditions by in situ depositing polypyrrole thin films on blank flexible poly(ethylene terephthalate), or PET, substrates from aqueous media in which oxidative polymerization of pyrrole was taking place. The obtained flexible all-polymer conductive substrates were semi-transparent with cohesive coatings of AQSA{sup -}doped polypyrrole thin films (thickness {approx}55 nm). The all-polymer flexible conductive substrates had sheet resistivity {approx}40 k{Omega} {open_square}{sup -1}and T% transparency against air {approx}78% at 600 nm. The light-valves fabricated using the above all-polymer conductive substrates showed {approx}50% transparency against air at 600 nm when 4 V {mu}m{sup -1} electric field was applied.

  3. Chemical synthesis of α-La{sub 2}S{sub 3} thin film as an advanced electrode material for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Patil, S.J.; Kumbhar, V.S.; Patil, B.H.; Bulakhe, R.N.; Lokhande, C.D., E-mail: l_chandrakant@yahoo.com

    2014-10-25

    Highlights: • The simple, chemical method used for synthesis of lanthanum sulphide thin films. • The lanthanum sulphide thin film surface exhibited porous microstructure. • The lanthanum sulphide thin film electrode is used for supercapacitor application. - Abstract: α-La{sub 2}S{sub 3} thin films have been synthesized for the first time by successive ionic layer adsorption and reaction (SILAR) method and used for supercapacitor application. These films are characterized for crystal structure, surface morphology and wettability studies using X-ray diffraction (XRD), Fourier Transform-Raman (FT-Raman) spectroscopy, scanning electron microscopy (SEM) and contact angle measurements. The electrochemical supercapacitive performance of α-La{sub 2}S{sub 3} electrode is evaluated by cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. From the electrochemical study, it is seen that α-La{sub 2}S{sub 3} electrode delivers high specific capacitance of 256 F g{sup −1} at scan rate of 5 mV s{sup −1} with cycling stability of 85% over 1000 cycles. Such La{sub 2}S{sub 3} electrode has great application in supercapacitor device for energy storage.

  4. Digital simulation of chronoamperometry at a disk electrode under a flat polymer film containing an enzyme

    DEFF Research Database (Denmark)

    Britz, Dieter; Strutwolf, Jörg

    2015-01-01

    Current-time and steady state current behaviour were simulated for an ultramicrodisk electrode (UMDE) inlaid flush with an insulating plane and overlaid by a flat film of polymer containing an enzyme, of various film thicknesses and essentially infinite extent. Steady state currents go through a maximum...... for some film thickness H, and then approach a constant value for thicker films. This constant value is the same as that for the diffusion limited current at an UMDE in a semi-infinite medium. Response times to 95% of the steady state current, for thin films are shorter than can be achieved using a flat disk...... electrode and a hemispherical polymer drop, but for large H they are slightly longer for comparable film thicknesses/radii. A hemispherical electrode under a hemispherical polymer drop, however, behaves much like the present arrangement....

  5. Annealing of RuO 2 and Ru Bottom Electrodes and Its Effects on the Electrical Properties of (Ba,Sr)TiO 3 Thin Films

    Science.gov (United States)

    Ahn, Joon-Hyung; Choi, Won-Youl; Lee, Won-Jae; Kim, Ho-Gi

    1998-01-01

    Crystalline structures and surface morphologies of annealed RuO2 and Ru thin films were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The annealing was performed in oxygen and argon ambient and high vacuum in the temperature range of 400 800° C. In oxygen ambient annealing, the surface morphology was drastically changed due to the evaporation of ruthenium dioxides in the form of RuO3 and RuO4. Annealed RuO2 thin film in vacuum was reduced to the Ru metal phase. The actual variation of RuO2 bottom electrodes during the deposition of (Ba,Sr)TiO3 (BST) thin films and the effects of the thermal stability of bottom electrodes on electrical properties of BST thin films deposited on RuO2/SiO2/Si were also investigated.

  6. Composition analysis of the passive film on the carbon electrode of a lithium-ion battery with an EC-based electrolyte

    Science.gov (United States)

    Yang, C. R.; Wang, Y. Y.; Wan, C. C.

    This work examines the formation of a passive film on the carbon electrode of lithium-ion batteries. With a single solvent of EC (ethylene carbonate), the structure of the passive film is found to be (CH 2OCOOLi) 2. In a DEC (diethyl carbonate) or DMC (dimethyl carbonate) system, C 2H 5OCOOLi and Li 2CO 3 are formed on the surface of the carbon electrode. According to results from mass spectra, CO 2 gas is the main product when EC is decomposed. By contrast, DEC is decomposed into CO and C 2H 6, and DMC into CO and CH 4. These findings suggest that the composition of the passive film depends on the chosen solvent. In a binary solvent system which contains EC, the passive film contains chiefly (CH 2OCOOLi) 2, which is identical to a single EC solvent system.

  7. Bismuth-based oxide semiconductors: Mild synthesis and practical applications

    Science.gov (United States)

    Timmaji, Hari Krishna

    In this dissertation study, bismuth based oxide semiconductors were prepared using 'mild' synthesis techniques---electrodeposition and solution combustion synthesis. Potential environmental remediation and solar energy applications of the prepared oxides were evaluated. Bismuth vanadate (BiVO4) was prepared by electrodeposition and solution combustion synthesis. A two step electrosynthesis strategy was developed and demonstrated for the first time. In the first step, a Bi film was first electrodeposited on a Pt substrate from an acidic BiCl3 medium. Then, this film was anodically stripped in a medium containing hydrolyzed vanadium precursor, to generate Bi3+, and subsequent BiVO4 formation by in situ precipitation. The photoelectrochemical data were consistent with the in situ formation of n-type semiconductor films. In the solution combustion synthesis procedure, BiVO4 powders were prepared using bismuth nitrate pentahydrate as the bismuth precursor and either vanadium chloride or vanadium oxysulfate as the vanadium precursor. Urea, glycine, or citric acid was used as the fuel. The effect of the vanadium precursor on the photocatalytic activity of combustion synthesized BiVO 4 was evaluated in this study. Methyl orange was used as a probe to test the photocatalytic attributes of the combustion synthesized (CS) samples, and benchmarked against a commercial bismuth vanadate sample. The CS samples showed superior activity to the commercial benchmark sample, and samples derived from vanadium chloride were superior to vanadium oxysulfate counterparts. The photoelectrochemical properties of the various CS samples were also studied and these samples were shown to be useful both for environmental photocatalytic remediation and water photooxidation applications. Silver bismuth tungstate (AgBiW2O8) nanoparticles were prepared for the first time by solution combustion synthesis by using silver nitrate, bismuth nitrate, sodium tungstate as precursors for Ag, Bi, and W

  8. Poly(brilliant green) and poly(thionine) modified carbon nanotube coated carbon film electrodes for glucose and uric acid biosensors

    OpenAIRE

    Ghica, M. Emilia; Christopher M. A. Brett

    2014-01-01

    Poly(brilliant green) (PBG) and poly(thionine) (PTH) films have been formed on carbon film electrodes (CFEs) modified with carbon nanotubes (CNT) by electropolymerisation using potential cycling. Voltammetric and electrochemical impedance characterisation were performed. Glucose oxidase and uricase, as model enzymes, were immobilised on top of PBG/CNT/CFE and PTH/CNT/CFE for glucose and uric acid (UA) biosensing. Amperometric determination of glucose and UA was carried out in phosphate buffer...

  9. Electrical conductivity dependence of thin metallic films of Au and Pd as a top electrode in capacitor applications

    International Nuclear Information System (INIS)

    Electrical conductivity dependence of thin metallic films of Au and Pd over the different perovskites was investigated. It is found from electrical properties that crystallographic growth orientation of Au and Pd thin layers attained from X-ray diffraction results indicate the slop of current (I)-voltage (V) plots. Besides, surface morphology and topography was considered using Field Emission Scanning Electron Microscopy and Atomic Force Microscopy, respectively. Obtained results showed the Stranski-Krastanov growth of the Pd and Au. Indeed, diminishing of the root-mean-square roughness of Pd/BiMnO3/SrTiO3 following by Au deposition should be concerned due to growth of Au onto the crack-like parts of the substrate. These crack-like parts appeared due to parasitic phases of the Bi-Mn-O system mainly Mn3O4 (l 0 l) and Mn3O4 (0 0 4 l). The different response in the electrical properties of heterostructures suggests that electrical conductance of the Au and Pd thin metallic films have the crystallographic orientation dependence. Furthermore, polycrystallinity of the thin metallic films are desired in electrode applications due to increase the conductivity of the metallic layers.

  10. ITO electrode modified by self-assembling multilayer film of polyoxometallate on poly(vinyl alcohol) nanofibers and its electrocatalytic behavior

    International Nuclear Information System (INIS)

    Poly(vinyl alcohol) (PVA) nanofiber mats were collected on indium tin oxide (ITO) substrate by electrospinning method. A multilayer film composed of α-[P2W18O62]6- (abbr. P2W18), a polyoxometallate (POM) anion, and poly(diallymethylammonium chloride) (abbr. PDDA) was fabricated by layer-by-layer (LBL) self-assembly technique on the PVA/ITO electrode. The PDDA/P2W18 multilayer film could be unselectively or selectively deposited on the PVA/ITO electrode via changing the amount of PVA nanofibers on the ITO substrate. The scanning electron microscope (SEM) images showed that when the electrospun time was short the PDDA/P2W18 multilayer film was unselectively deposited on PVA nanofiber mats because the amount of PVA nanofibers was too little to cover most of the ITO substrate. However, when the electrospun time was long enough, the PDDA/P2W18 multilayer film was selectively deposited on PVA nanofiber mats because of the larger surface area and higher surface energy of PVA nanofibers in comparison with the flat ITO substrate. Growth process of the multilayer film was determined by cyclic voltammetry (CV). Electrocatalytic effects of the PDDA/P2W18 multilayer film unselectively and selectively deposited on the PVA/ITO electrode on NO2- were observed

  11. Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

    OpenAIRE

    Shi C; Zhitomirsky I

    2010-01-01

    Abstract Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the...

  12. A Comparison of Modifications Induced by Li3+ and Ag14+ Ion Beam in Spectroscopic Properties of Bismuth Alumino-Borosilicate Glass Thin Films

    Directory of Open Access Journals (Sweden)

    Ravneet Kaur

    2013-01-01

    Full Text Available Ion irradiation effects on the glass network and structural units have been studied by irradiating borosilicate glass thin film samples with 50 MeV Li3+ and 180 MeV Ag14+ swift heavy ions (SHI at different fluence rates ranging from 1012 ions/cm2 to 1014 ions/cm2. Glass of the composition (65-x Bi2O3-10Al2O3-(65-y B2O3-25SiO2 (x = 45, 40; y = 20, 25 has been prepared by melt quench technique. To study the effects of ionizing radiation, the glass thin films have been prepared from these glasses and characterized using XRD, FTIR, and UV-Vis spectroscopic techniques. IR spectra are used to study the structural arrangements in the glass before and after irradiation. The values of optical band gap, Urbach energy, and refractive index have been calculated from the UV-Vis measurements. The variation in optical parameters with increasing Bi2O3 content has been analyzed and discussed in terms of changes occurring in the glass network. A comparative study of the influence of Li3+ ion beam on structural and optical properties of the either glass system with Ag14+ ion is done. The results have been explained in the light of the interaction that SHI undergo on entering the material.

  13. Sheet resistance, transmittance, and chromatic property of CNTs coated with PEDOT:PSS films for transparent electrodes of touch screen panels

    International Nuclear Information System (INIS)

    This study demonstrates hybrid-type transparent electrodes based on carbon nanotubes (CNTs) that possess characteristics desirable for touch screen panels. This has been accomplished by depositing CNTs via spray-coating and then depositing thin conductive polymer (such as PEDOT:PSS) films on the CNTs via spin-coating. For all of the samples such as CNTs, PEDOT:PSS, and hybrid (i.e., PEDOT:PSS-coated CNTs), their surface morphologies, sheet resistances, visible transmittances, and chromatic properties are characterized as functions of their preparation conditions. In the PEDOT:PSS-coated CNTs, the PEDOT:PSS particles fill up the voids between tubes in CNTs, forming a conduction bridge for electron transfer and eventually decreasing the sheet resistance of the hybrid electrode. Also, the hybrid electrode reveals a superior color property compared with that of CNTs or the PEDOT:PSS single electrode due to the complementary color relation between CNTs and PEDOT:PSS. Experimental results show that the fabricated hybrid-type electrodes can simultaneously satisfy the requirements necessary for transparent electrodes of touch screen panels such as the sheet resistance requiring to be lower than 100 Ω/sq, visible transmittance higher than 80%, and yellowness approaching to zero. - Highlights: • Hybrid-type (PEDOT:PSS-coated CNTs) electrodes for touch panels are fabricated. • PEDOT:PSS films are coated via spin-coating on spray-deposited CNTs. • Hybrid electrodes are fabricated by varying the thickness of CNTs and PEDOT:PSS. • The resistance, transmittance, and color properties have been analyzed. • Hybrid electrodes satisfy electrical and optical properties for touch panels

  14. Sensitive electrochemical determination of trace cadmium on a stannum film/poly(p-aminobenzene sulfonic acid)/electrochemically reduced graphene composite modified electrode

    International Nuclear Information System (INIS)

    In this study, a novel stannum film/poly(p-aminobenzene sulfonic acid)/graphene composite modified glassy carbon electrode (GCE) was prepared by using electrodeposition of exfoliated graphene oxide, electropolymerization of p-aminobenzene sulfonic acid (p-ABSA) and in situ plating stannum fim methods, successively. This sensor was further used for sensitive determination of trace cadmium ions by square wave anodic stripping voltammetry (SWASV). The morphologies and electrochemistry properties of the modified electrode were characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and linear sweep voltammetry. It was found that the formed graphene layer on the top of GCE could remarkably facilitate the electron transfer and enlarge the specific surface area of the electrode. While the poly(p-ABSA) film could effectively increase the adhesion and stability of graphene layer, enhance ion-exchange capacity and prevent the macromolecule in real samples absorbing on the surface of electrode. By combining co-deposits ability with heavy metals of stannum film, the obtained electrode exhibited a good stripping performance for the analysis of Cd(II). Under the optimum conditions, a linear response was observed in the range from 1.0 to 70.0 μgL−1 with a detection limit of 0.05 μgL−1 (S/N = 3). The sensor was further applied to the determination of cadmium ions in real water samples with satisfactory results

  15. Facile fabrication of sub-100 nm mesoscale inverse opal films and their application in dye-sensitized solar cell electrodes.

    Science.gov (United States)

    Lee, Jung Woo; Lee, Jaemin; Kim, Cheolho; Cho, Chang-Yeol; Moon, Jun Hyuk

    2014-10-28

    Inverse opal (IO) films with mesoporous structures hold promise as high-performance electrodes for various photoelectrochemical devices because of their high specific area as well as their fully connected pore structure. A great challenge to their use is obtaining an intact film of mesoscale colloidal crystals as a template. Here, using the plate-sliding coating method coupled with hot air flow, we successfully deposited mesoscale colloidal crystals onto the substrate. A TiO2 mesoscale IO (meso-IO) with 70 nm pores was then successfully fabricated via atomic layer deposition of TiO2 and subsequent removal of the template. As a photoelectrochemical electrode, the meso-IO structure exhibits enhanced charge transport properties as well as a high specific area. Moreover, dye-sensitized solar cells fabricated using the meso-IO electrode exhibit a higher photocurrent and cell efficiency than a cell constructed using a conventional TiO2 nanoparticle electrode. This meso-IO film provides a new platform for developing electrodes for use in various energy storage and conversion devices.

  16. Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

    KAUST Repository

    Phadke, Sujay

    2011-09-30

    Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ∼5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2-D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter-wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter-wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires. Solution processed Gallium doped ZnO nanowires are aligned on substrates using an innovative shear coating technique. Nanowire alignment has shown improvement in ZnO nanowire transparent electrode conductivity. 2D network simulations in conjunction with electrical measurements have revealed different regimes of operation of nanowire thin films and provided a guideline for improving electrical performance of nanowire electrodes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Graphene/Nafion composite film modified glassy carbon electrode for simultaneous determination of paracetamol, aspirin and caffeine in pharmaceutical formulations.

    Science.gov (United States)

    Yiğit, Aydın; Yardım, Yavuz; Çelebi, Metin; Levent, Abdulkadir; Şentürk, Zühre

    2016-09-01

    A graphene-Nafion composite film was fabricated on the glassy carbon electrode (GR-NF/GCE), and used for simultaneous determination of paracetamol (PAR), aspirin (ASA) and caffeine (CAF). The electrochemical behaviors of PAR, ASA and CAF were investigated by cyclic voltammetry and square-wave adsorptive anodic stripping voltammetry. By using stripping one for simultaneous determination of PAR, ASA and CAF, their electrochemical oxidation peaks appeared at +0.64, 1.04 and 1.44V, and good linear current responses were obtained with the detection limits of 18ngmL(-1) (1.2×10(-9)M), 11.7ngmL(-1) (6.5×10(-8)M) and 7.3ngmL(-1) (3.8×10(-8)M), respectively. Finally, the proposed electrochemical sensor was successfully applied for quantifying PAR, ASA and CAF in commercial tablet formulations. PMID:27343573

  18. Improvement in luminance efficiency of organic light emitting diodes by suppression of secondary electron bombardment of substrate during sputter deposition of top electrode films

    Science.gov (United States)

    Hamaguchi, Daichi; Kobayashi, Shin-ichi; Uchida, Takayuki; Sawada, Yutaka; Lei, Hao; Hoshi, Yoichi

    2016-10-01

    In this study, we investigated the degradation mechanisms of the luminance performance of organic light-emitting diodes (OLEDs) when their top electrode films were deposited by sputter deposition process. During the sputter deposition of the top electrode films, the suppression of the incidence of high-energy electrons on the substrate was attempted using various methods. As a result, we found that during electrode deposition, the incidence of the high-energy secondary electrons, which were emitted from the target surface, on the substrate was the main cause of the significant degradation of the luminance performance. It was also found that the application of a magnetic field by setting permanent magnets near the substrate holder and the insertion of a shield plate near the target cathode were effective in suppressing the incidence of secondary electrons on the substrate.

  19. Thin Film Nanocrystalline TiO2 Electrodes: Dependence of Flat Band Potential on pH and Anion Adsorption.

    Science.gov (United States)

    Minella, M; Maurino, V; Minero, C; Pelizzetti, E

    2015-05-01

    Thin nanocrystalline TiO2 films were produced on ITO conductive glass by dip-coating of a sol-gel TiO2 precursor. The transparent films were characterized from the optical and structural point of view with UV-Vis, Spectroscopic Ellipsometry, Raman and X-ray photoelectron spectroscopies, the roughness of the coating by AFM. The changes in the electrochemical properties features of ITO/TiO2 electrodes were evaluated in the presence of different electrolytes (KCI, Na2SO4 and phosphate buffer) with the aim to clarify the role of the ion adsorption on the structure of the electrical double layer. Electrochemical tests (Cyclic Voltammetry, CV, and Impedance Electrochemical Spectroscopy, EIS) showed a strong influence of the electrolyte properties on the semiconductor band edge position in the electrochemical scale and on band bending. The CV profiles recorded can be explained by considering that the interface capacity is due to the charging of surface states (e.g., Ti(IV) surface sites coordinated by oxygen atoms, ≡Ti-OH or Ti-O-Ti). The surface charge is strongly affected also by the density and nature of adsorbed ions and by dissociation of surficial OH. Of interest the fact that for the produced nanocrystalline electrodes the flat band potential, measured from the Mott-Schottky analysis of the space charge layer capacity obtained with EIS, showed a non Nernstian behavior with the pH probably caused by a change in the surface acidity as a consequence of specific anion adsorption. The modulation of flat band potential with adsorbed ions is of interest for many applications, in particular for photocatalysis (change in the redox potential of photogenerated carriers) and for photovoltaic applications like DSSC (change in the photopotentials).

  20. Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode

    Science.gov (United States)

    Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

    2016-01-01

    Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C–800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction. PMID:27563893

  1. Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

    Directory of Open Access Journals (Sweden)

    Chuan Lung Chuang

    2015-01-01

    Full Text Available Indium tin oxide (ITO thin films were grown on glass substrates by direct current (DC reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were -1.6E+20 cm−3, 2.7E+01 cm2/Vs, 1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.

  2. Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode.

    Science.gov (United States)

    Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

    2016-01-01

    Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C-800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction.

  3. Crystal structure and electrochemical behaviors of Pt/mischmetal film electrodes

    Institute of Scientific and Technical Information of China (English)

    张文魁; 杨晓光; 马淳安; 王云刚; 余厉阳

    2003-01-01

    The Ml(La-rich mischmetal) films with a thin Pt layer on the substrate of chemically coarsen ITO glassor silicon slices were prepared by magnetic sputtering technique. The crystal structure and surface morphology ofthe films were investigated by X-ray diffraction(XRD) analysis and atomic force microscopy(AFM), respectively.The electrochemical hydridation/dehydridation behaviors of the films in KOH solution were studied by using cyclicvoltammagraph and electrochemical impedance spectrum(EIS) as well. The AFM results show that the Pt cover lay-er on the M1 films is of island structure with a grain of 150 - 200 nm in size. The presence of a thin Pt layer can pro-vide sufficient high electrocatalytic activity for the electrochemical charge-transfer reaction. The electrochemical re-duction and oxidation reaction occur on the Pt layer, and the diffusion of H into the Ml film is the rate-controlledstep. The Pt coatings also act as protective layers, preventing oxidation and/or poisoning of the underlying Ml filmsin air.

  4. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Directory of Open Access Journals (Sweden)

    Moulin Etienne

    2015-01-01

    Full Text Available The optical and electrical properties of transparent conductive oxides (TCOs, traditionally used in thin-film silicon (TF-Si solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-μm-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  5. Electrochemical Rectification of Redox Mediators Using Porphyrin-Based Molecular Multilayered Films on ITO Electrodes.

    Science.gov (United States)

    Civic, Marissa R; Dinolfo, Peter H

    2016-08-10

    Electrochemical charge transfer through multilayer thin films of zinc and nickel 5,10,15,20-tetra(4-ethynylphenyl) porphyrin constructed via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry was examined. Current rectification toward various outer-sphere redox probes is revealed with increasing numbers of layers, as these films possess insulating properties over the neutral potential range of the porphyrin, then become conductive upon reaching its oxidation potential. Interfacial electron transfer rates of mediator-dye interactions toward [Co(bpy)3](2+), [Co(dmb)3](2+), [Co(NO2-phen)3](2+), [Fe(bpy)3](2+), and ferrocene (Fc), all outer-sphere redox species, were measured by hydrodynamic methods. The ability to modify electroactive films' interfacial electron transfer rates, as well as current rectification toward redox species, has broad applicability in a number of devices, particularly photovoltaics and photogalvanics.

  6. Determination of biogenic amines from electrocatalytic responses of graphite electrodes modified with metallic osmium or an osmium oxide-ruthenium cyanide film

    International Nuclear Information System (INIS)

    Particles of osmium or an inorganic polymeric film of osmium oxide-ruthenium cyanide (OsO-RuCN) electrodeposited on glassy carbon (GC) electrocatalyze the oxidation of dopamine (DA), adrenaline (AD), and noradrenaline (NAD). It is found that these biogenic amines are determined with a high sensitivity by oxidation at an electrode with an OsO-RuCN film. Procedures for the voltammetric determination of DA, AD, or NAD at a composite film electrode are developed. The currents of the substrate oxidation are linear functions of the concentrations in the ranges from 5x10-7 to 1x10-3 M for DA and from 1x10-6 to 1x10-3 M for AD and NAD

  7. Spectroscopic Characterization of Poly(ortho-Aminophenol) Film Electrodes: A Review Article

    OpenAIRE

    Ricardo Tucceri; Pablo Maximiliano Arnal; Alberto Néstor Scian

    2013-01-01

    This paper refers to spectroscopic studies carried out to identify the products of o-aminophenol electro-oxidation and elucidate the structure of electrochemically synthesized poly(o-aminophenol) (POAP) films. Spectroscopic studies of the redox conversion of POAP are also reviewed.

  8. Spectroscopic Characterization of Poly(ortho-Aminophenol Film Electrodes: A Review Article

    Directory of Open Access Journals (Sweden)

    Ricardo Tucceri

    2013-01-01

    Full Text Available This paper refers to spectroscopic studies carried out to identify the products of o-aminophenol electro-oxidation and elucidate the structure of electrochemically synthesized poly(o-aminophenol (POAP films. Spectroscopic studies of the redox conversion of POAP are also reviewed.

  9. Injecting electrode controlled electronic transport across Fe{sub 3}O{sub 4} film-Si interfacial structure

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Surajit; Srivastava, Neelabh; Srivastava, P.C., E-mail: pcsrivastava50@gmail.com

    2014-11-05

    Highlights: • CPP I–V measurements have been carried out on Fe{sub 3}O{sub 4}/SiO{sub 2}/Si heterostructure. • Verwey transition has been found for injection from Fe{sub 3}O{sub 4} film. • Low temperature GMR of ∼200% has also been observed for the same injection. • The features of injecting electrodes have been found from CPP I–V data. - Abstract: A study of electronic transport has been carried out across a half-metallic Fe{sub 3}O{sub 4} film–nSi interfacial structure in CPP mode with an interfacial SiO{sub 2} layer of <5 nm. It has been measured with and without applied magnetic field along the plane of the interface between 25 K and 300 K to investigate the role of half-metallic Fe{sub 3}O{sub 4} layer on the transport. The electronic transport has shown a distinct behaviour for the reverse bias in which injection takes place from metallic film of Fe{sub 3}O{sub 4} to silicon than for the forward bias in which injection takes place from silicon to metallic Fe{sub 3}O{sub 4} side. It has been found that the reverse bias current shows a tunnel transport, Verwey transition like feature and low temperature positive GMR, evidencing spin involved transport from Fe{sub 3}O{sub 4} to semiconductor side. Whereas the forward bias current has not shown any of the above features but a thermionic controlled transport, showing a change of resistance with temperature as of semiconductor silicon. Thus, it has been found that the transport is controlled by physical properties of the injecting electrode. The study has shown that the transport below Verwey transition temperature (T{sub V}) for the Fe{sub 3}O{sub 4} film interfacial structure is also related to its electronic spins. The observed GMR of ∼200% at low temperature (for reverse bias current only) has been discussed as the effect of electronic spin scattering. Our unique observations from simple measurements of CPP I–V across the interfacial structure of Fe{sub 3}O{sub 4}–nSi seem significant to

  10. A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine

    Directory of Open Access Journals (Sweden)

    Shouzhuo Yao

    2005-04-01

    Full Text Available Tannic acid-doped polypyrrole (PPY/TA films have been grown on goldelectrodes for selective electrochemical detection of dopamine (DA. Electrochemicalquartz crystal microbalance (EQCM studies revealed that, in vivid contrast toperchlorate-doped polypyrrole films (PPY/ClO4-, the redox switching of PPY/TA filmsin aqueous solutions involved only cation transport if the solution pH was greater than3~4. The PPY/TA Au electrodes also exhibited attractive permselectivity forelectroactive cations, namely, effectively blocking the electrochemical reactions ofanionic ferricyanide and ascorbic acid (AA while well retaining the electrochemicalactivities of hexaammineruthenium (III and dopamine as cationic species. A 500 HzPPY/TA film could effectively block the redox current of up to 5.0 mM AA. Thecoexistence of ascorbic acid in the measurement solution notably enhanced the currentsignal for dopamine oxidation, due probably to the chemical regeneration of dopaminethrough an ascorbic acid-catalyzed reduction of the electro-oxidation product ofdopamine (EC’ mechanism, and the greatest amplification was found at an ascorbic acidconcentration of 1.0 mM. The differential pulse voltammetry peak current for DAoxidation was linear with DA concentration in the range of 0 to 10 μM, with sensitivityof 0.125 and 0.268 μA/μM, as well as lower detection limit of 2.0 and 0.3 μM in a PBSsolution without AA and with 1.0 mM coexisting AA, respectively.

  11. Photoelectrocatalytic Degradation of Sodium Oxalate by TiO2/Ti Thin Film Electrode

    Directory of Open Access Journals (Sweden)

    Chen-Yu Chang

    2012-01-01

    Full Text Available The photocatalytically active TiO2 thin film was deposited on the titanium substrate plate by chemical vapor deposition (CVD method, and the photoelectrocatalytic degradation of sodium oxalate was investigated by TiO2 thin film reactor prepared in this study with additional electric potential at 365 nm irradiation. The batch system was chosen in this experiment, and the controlled parameters were pH, different supporting electrolytes, applied additional potential, and different electrolyte solutions that were examined and discussed. The experimental results revealed that the additional applied potential in photocatalytic reaction could prohibit recombination of electron/hole pairs, but the photoelectrocatalytic effect was decreased when the applied electric potential was over 0.25 V. Among the electrolyte solutions added, sodium sulfate improved the photoelectrocatalytic effect most significantly. At last, the better photoelectrocatalytic degradation of sodium oxalate occurred at pH 3 when comparing the pH influence.

  12. Optimization of Sputtering Condition of IrOx Thin Film Stimulation Electrode for Retinal Prosthesis Application

    International Nuclear Information System (INIS)

    We have optimized the sputtering condition of the RF sputtering deposition for the fabrication of the iridium oxide thin film used in retinal prosthesis applications. The deposited IrOx thin films were characterized by using the cyclic voltammetry method and the charge delivery capacity was calculated from the integral of the generic CV curve. From the experimental results, the charge delivery capacity of IrOx under the best sputtering condition was improved to more than 50 times that of Pt. We also verified from our in vivo experiment results that IrOx has a better charge delivery capacity than that of Pt. The in vitro and in vivo experimental results also show that IrOx is a promising candidate for retinal prosthesis applications.

  13. Fabrication of a nanostructure thin film on the gold electrode using continuous pulsed-potential technique and its application for the electrocatalytic determination of metronidazole

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, B., E-mail: rezaei@cc.iut.ac.i [Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of); Damiri, S. [Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111 (Iran, Islamic Republic of)

    2010-02-01

    This paper demonstrates a new and simple approach based on a continuous pulsed-potential (CPP) method for the preparation of reproducible nanostructure and nanoporous thin film on the polycrystalline gold electrodes. The fabrication process involves pulsed electrochemical oxidation and reduction of gold electrode in the sulfuric acid solution without using additional reagents. Effect of various parameters including pulse height, pulse time, pulse number and relaxation time on the enhancing of hexacyanoferrate (HCF) redox behaviour, as a probe, were investigated and optimized. Electrochemical, scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies show the formation of a nanoporous thin film and sharp nanostructure edges on the gold electrode that considerably enhances electrocatalysis of HCF and provides useful conditions for the electroanalysis by the modified electrode. In addition, the electrocatalytic behaviour of this modified electrode was exploited as a sensitive detection system for the determination of metronidazole in pharmaceutical and human urine samples, by using cyclic voltammetry (CV) and hydrodynamic methods. Under optimized conditions, this method shows linear dynamic ranges of 0.5-10.0 and 20.0-800.0 muM with the calculated detection limit (S/N = 3) of 0.15 muM and a precision of <5%.

  14. High optical transmittance of aluminum ultrathin film with hexagonal nanohole arrays as transparent electrode

    KAUST Repository

    Du, Qing Guo

    2016-02-24

    We fabricate samples of aluminum ultrathin films with hexagonal nanohole arrays and characterize the transmission performance. High optical transmittance larger than 60% over a broad wavelength range from 430 nm to 750 nm is attained experimentally. The Fano-type resonance of the excited surface plasmon plaritons and the directly transmitted light attribute to both of the broadband transmission enhancement and the transmission suppression dips. © 2016 Optical Society of America.

  15. Electrode and solid electrolyte thin films for secondary lithium-ion batteries

    Science.gov (United States)

    Chen, C. H.; Kelder, E. M.; Schoonman, J.

    Electrostatic spray deposition (ESD) was employed to prepare thin layers of Li 1.2Mn 2O 4 (nominal composition) and BPO 4:0.035Li 2O for all-solid-state thin film lithium-ion batteries. The relationships between layer morphologies and deposition conditions such as solvent composition of the precursor solutions and substrate temperature were investigated. It was found that a low substrate temperature and/or high boiling point of the solvent may lead to a relatively dense structure. Reticular porous structures are formed, if films were deposited at 250°C and a mixture of 85 vol.% butyl carbitol and 15 vol.% ethanol was used as the solvent. The Li 1.2Mn 2O 4 layers, formed in the 250-400°C temperature range, were amorphous or micro-crystalline. After annealing beyond 600 °C, they could be crystallized into a spinel-structured material. Glassy BPO 4:0.035Li 2O layers could fill the pores of porous Li 1.2Mn 2O 4 layers to form a dense intermediate electrolyte layer. Thin-film rocking-chair batteries, Li 1.2Mn 2O 4|BPO 4:0.035Li 2O|Li 1.2Mn 2O 4|Al, were prepared and revealed an open-circuit voltage of about 1.2 V after charging.

  16. Bismuth nanoparticles for phenolic compounds biosensing application.

    Science.gov (United States)

    Mayorga-Martinez, Carmen C; Cadevall, Miquel; Guix, Maria; Ros, Josep; Merkoçi, Arben

    2013-02-15

    The rapid determination of trace phenolic compounds is of great importance for evaluating the total toxicity of contaminated water samples. Nowadays, electrochemical tyrosinase (Tyr) based biosensors constitute a promising technology for the in situ monitoring of phenolic compounds because of their advantages such as high selectivity, low production cost, promising response speed, potential for miniaturization, simple instrumentation and easy automatization. A mediator-free amperometric biosensor for phenolic compounds detection based on the combination of bismuth nanoparticles (BiNPs) and Tyr for phenol detections will be hereby reported. This is achieved through the integration of BiNPs/Tyr onto the working electrode of a screen printed electrode (SPE) by using glutaraldehyde as a cross-linking agent. BiNPs/Tyr biosensor is evaluated by amperometric measurements at -200 mV DC and a linear range of up to 71 μM and 100 μM and a correlation coefficient of 0.995 and 0.996 for phenol and catechol, respectively. The very low DC working potential ensures the avoidance of interferences making this biosensor an advantageous device for real sample applications. In addition, the response mechanism including the effect of BiNPs based on electrochemical studies and optical characterizations will be also discussed. The obtained results may open the way to many other BiNPs applications in the biosensing field.

  17. Highly sensitive response to dopamine at a modified electrode involving a composite film with Au nanoparticles dispersed in a fluorocarbon polymer

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new approach for the highly sensitive detection of dopamine by a novel composite film involving gold nanoparticles trapped in a negatively-charged fluorocarbon polymer (Nafion) on a glassy carbon (GC) electrode fabricated by a simple method is described. Gold nanoparticles with an average diameter of 2.3 nm ± 0.2 nm are dispersed throughout the whole Nafion film. The introduction of gold nanoparticles into the Nafion film not only gives a highly active electrode surface area but also increases the conductivity of the Nafion film and the resulting Au/Nafion/GC electrode combines the advantages of the properties of gold nanoparticles and the selective pre-concentration ability of Nafion. For positively charged dopamine, the results show a decrease in the redox peak separation and a high sensitivity. The oxidation peak current of dopamine was shown to vary linearly with dopamine concentration over a wide range from 0.4 to 50.0 μmol/L with a detection limit of 0.3 μmol/L. Negatively charged ascorbic acid shows no redox waves at concentrations up to 1.0 ×10-4 mol/L.

  18. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Preparation and Characterization of BPO Film as Electrode for Using of FeRAM

    Science.gov (United States)

    Wen, Xin-Yi; Yu, Jun; Wang, Yun-Bo; Zhou, Wen-Li; Gao, Jun-Xiong; Chu, Xiao-Hui

    2008-07-01

    Conductive perovskite BaPbO3 (BPO) films as a potential electrode material of PZT capacitors used in ferroelectric random access memory are prepared by rf magnetron sputtering. An x-ray diffractometer and standard four probe method are employed to investigate the dependence of growth conditions on crystal structure and conductivity of BPO films. It is found that BPO films with perovskite phase can be obtained at substrate temperatures above 425° C, and the sample with the lowest resistivity is obtained at 450° C under pure argon atmosphere. Using this BPO film as electrode, ferroelectric properties of BPO/PZT/BPO and Pt/PZT/BPO sandwiched structures are evaluated. Their remanent polarization and coercive field are 36.6μC/cm2 (81.3kV/cm) and 36.9μC/cm2 (89.1 kV/cm), respectively. The coercive field of the former structure is lower than that of the latter, but remanent polarizations are almost the same. In addition, the results imply that BPO electrode is helpful to improve the fatigue resistance of PZT. The reasons are discussed.

  19. In situ synthesis of porous array films on a filament induced micro-gap electrode pair and their use as resistance-type gas sensors with enhanced performances.

    Science.gov (United States)

    Xu, Zongke; Duan, Guotao; Zhang, Hongwen; Wang, Yingying; Xu, Lei; Cai, Weiping

    2015-09-14

    Resistance-type metal-oxide semiconductor gas sensors with high sensitivity and low detection limit have been explored for practical applications. They require both sensing films with high sensitivity to target gases and an appropriate structure of the electrode-equipped substrate to support the sensing films, which is still challenging. In this paper, a new gas sensor of metal-oxide porous array films on a micro-gap electrode pair is designed and implemented by taking ZnO as a model material. First, a micro-gap electrode pair was constructed by sputtering deposition on a filament template, which was used as the sensor's supporting substrate. Then, the sensing film, made up of ZnO porous periodic arrays, was in situ synthesized onto the supporting substrate by a solution-dipping colloidal lithography strategy. The results demonstrated the validity of the strategy, and the as-designed sensor shows a small device-resistance, an enhanced sensing performance with high resolution and an ultralow detection limit. This work provides an alternative method to promote the practical application of resistance-type gas sensors.

  20. Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO2) thin films

    Science.gov (United States)

    Nordin, N.; Hashim, U.; Azizah, N.

    2016-07-01

    Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO2) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM. Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.

  1. Flexible Nb2O5 nanowires/graphene film electrode for high-performance hybrid Li-ion supercapacitors

    Science.gov (United States)

    Song, Hao; Fu, Jijiang; Ding, Kang; Huang, Chao; Wu, Kai; Zhang, Xuming; Gao, Biao; Huo, Kaifu; Peng, Xiang; Chu, Paul K.

    2016-10-01

    The hybrid Li-ion electrochemical supercapacitor (Li-HSC) combining the battery-like anode with capacitive cathode is a promising energy storage device boasting large energy and power densities. Orthorhombic Nb2O5 is a good anode material in Li-HSCs because of its large pseudocapacitive Li-ion intercalation capacity. Herein, we report a high-performance, binder-free and flexible anode consisting of long Nb2O5 nanowires and graphene (L-Nb2O5 NWs/rGO). The paper-like L-Nb2O5 NWs/rGO film electrode has a large mass loading of Nb2O5 of 93.5 wt% as well as short solid-state ion diffusion length, and enhanced conductivity (5.1 S cm-1). The hybrid L-Nb2O5 NWs/rGO paper electrode shows a high reversible specific capacity of 160 mA h g-1 at a current density of 0.2 A g-1, superior rate capability with capacitance retention of 60% when the current density increases from 0.2 to 5 A g-1, as well as excellent cycle stability. The Li-HSC device based on the L-Nb2O5/rGO anode and the cathode of biomass-derived carbon nanosheets delivers an energy density of 106 Wh kg-1 at 580 W kg-1 and 32 Wh kg-1 at a large power density of 14 kW kg-1. Moreover, the Li-HSC device exhibits excellent cycling performance without obvious capacitance decay after 1000 cycles.

  2. Simultaneous Automatic Electrochemical Detection of Zinc, Cadmium, Copper and Lead Ions in Environmental Samples Using a Thin-Film Mercury Electrode and an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Jiri Kudr

    2014-12-01

    Full Text Available In this study a device for automatic electrochemical analysis was designed. A three electrodes detection system was attached to a positioning device, which enabled us to move the electrode system from one well to another of a microtitre plate. Disposable carbon tip electrodes were used for Cd(II, Cu(II and Pb(II ion quantification, while Zn(II did not give signal in this electrode configuration. In order to detect all mentioned heavy metals simultaneously, thin-film mercury electrodes (TFME were fabricated by electrodeposition of mercury on the surface of carbon tips. In comparison with bare electrodes the TMFEs had lower detection limits and better sensitivity. In addition to pure aqueous heavy metal solutions, the assay was also performed on mineralized rock samples, artificial blood plasma samples and samples of chicken embryo organs treated with cadmium. An artificial neural network was created to evaluate the concentrations of the mentioned heavy metals correctly in mixture samples and an excellent fit was observed (R2 = 0.9933.

  3. Electrosynthesis of Bi{sub 2}O{sub 3} thin films and their use in electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, T.P.; Shinde, V.R.; Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur, Maharashtra 416004 (India); Han, Sung-Hwan [Department of Chemistry, Hanyang University, Sungdong-Ku, Haengdang-dong 17, Seoul (133-791 Korea)

    2006-10-27

    Bismuth oxide (Bi{sub 2}O{sub 3}) thin films are grown on copper substrates at room temperature by electrodeposition from an aqueous alkaline nitrate bath. The usefulness of electrochemically deposited Bi{sub 2}O{sub 3} for electrochemical supercapacitors is proposed for the first time. The supercapacitor properties of Bi{sub 2}O{sub 3} electrode are studied in aqueous NaOH solution. The Bi{sub 2}O{sub 3} electrode exhibits very good electrochemical supercapacitive characteristics as well as stability in aqueous NaOH electrolyte. The effect of electrolyte concentration, scan rate, and number of cycles on the specific capacitance of Bi{sub 2}O{sub 3} electrodes has been studied. The highest specific capacitance achieved with the electrodeposited Bi{sub 2}O{sub 3} films is 98Fg{sup -1}. (author)

  4. 修饰铂电极上Bi(Ⅲ)的示波双电位滴定法%Oscillo-Potentiometric Titration of Bismuth(Ⅲ)Using Modified Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    齐蕾; 齐同喜

    2011-01-01

    Bi ( Ⅲ ) modified Pt-electrode was prepared and the adsorption character of Bi ( Ⅲ ) on the electrode was studied by cyclic voltammetry. The mechanism of electrode response was discussed. A method using oscillo-potentiometry for the titration of Bi( Ⅲ) was described. In 0. 1 mol/L nitric acid solution (pH = 1.0) , Bi( Ⅲ) was titrated with EDTA, and two modified Pt-electrodes were used as bi-indicator electrode system. The end point of titration was determined by an abrupt maximum displacement of the fluorescence spot observed on the screen of the cathodic oscillograph. When Bi( Ⅲ) content was in the range of 1. 19 × 10 -4 ~ 1.44× 10-2 mol/L, the recovery was in the range of 99. 8% ~ 100. 1% and the detection limit was 1. 0 × 10-4 mol/L(S/N = 3). Furthermore, the modified electrode showed excellent stability and reproducibility. In 1.0 × 10-2 mol/L Bi ( Ⅲ ) solution, the values of end point potentials obtained from 7 continuous determinations were all around 100 mV, and the relative standard deviation( RSD) was 0.04%. Moreover, the proposed method has been used in the determination of Bi ( Ⅲ) contained in samples with recoveries of 99. 5%~100. 5% and RSD(n = 7) less than 0. 25% , which are in accordance with the indicator method.%制备了Bi(Ⅲ)修饰铂电极,用循环伏安法表征了Bi(Ⅲ)在电极上的吸附特性,探讨了电极的响应机理.通过优化实验条件,建立了一种测定Bi(Ⅲ)的示波双电位滴定法.在0.1 moL/L的硝酸溶液中(pH=1.0).用制备的修饰铂电极作为双指示电极,以EDTA标准溶液滴定Bi(Ⅲ),利用示波器屏幕上荧光点的显著最大位移指示滴定终点.Bi(Ⅲ)在1.19×10(-1)~1.44×10(-2)moL/L时,回收率为99.8%~100.1%,检出限(S,N=3)为1.0×10(-4)mol/L.该修饰电极具有良好的稳定性和重现性,在含有1.0×10(-2)moL/L Bi(Ⅲ)的溶液中,连续7次测定,所得终点电位值均在100 mV左右,其相对标准偏差(RSD)为0.04%.应用该

  5. Self-assembled multilayer films of sulfonated graphene and polystyrene-based diazonium salt as photo-cross-linkable supercapacitor electrodes.

    Science.gov (United States)

    Xiong, Zhiyuan; Gu, Tonghan; Wang, Xiaogong

    2014-01-21

    Photo-cross-linkable multilayer films composed of sulfonated reduced graphene oxide (SRGO) and polystyrene-based diazonium salt (PSDAS) were fabricated by electrostatic layer-by-layer (LbL) self-assembly. Polystyrene with narrow molecular weight distribution was synthesized by atom transfer radical polymerization (ATRP), and cationic PSDAS was prepared through nitration, reduction, and diazotization reactions. Negatively charged SRGO nanosheets were prepared through prereduced by NaBH4, modified by diazonium salt of sulfanilic acid, and then further reduced by hydrazine. The multilayer films were obtained by alternately dipping substrates in the PSDAS solution and SRGO dispersion in acidic conditions. The cross-linking between the components occurred during the multilayer formation process and was further achieved by the UV light irradiation after the film preparation. The assembling process and surface morphology of LbL multilayer films were monitored by UV-vis spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The cross-linking between SRGO and PSDAS was verified by attenuated total reflectance FTIR (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurement. The graphene nanosheets were found to be homogeneously distributed in the cross-linked network of the films. The large accessible surface area of graphene nanosheets and the cross-linking structure afforded the LbL films with high specific capacitance and excellent cyclic stability when used as supercapacitor electrodes. At a sweeping rate of 10 mV/s, the film with nine bilayers exhibited a specific capacitance of 150.4 F/g with ideal rectangular cyclic voltammogram. Large capacitance retention of 97% was observed after 10 000 charge-discharge cycles under the scanning rate of 1000 mV/s. This new approach for preparing graphene-containing multilayer films can be used to develop supercapacitor electrodes and other functional devices.

  6. Multi-input and -output logic circuits based on bioelectrocatalysis with horseradish peroxidase and glucose oxidase immobilized in multi-responsive copolymer films on electrodes.

    Science.gov (United States)

    Yu, Xue; Lian, Wenjing; Zhang, Jiannan; Liu, Hongyun

    2016-06-15

    Herein, poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethylmethacrylate) copolymer films were polymerized on electrode surface with a simple one-step method, and the enzyme horseradish peroxidase (HRP) was embedded in the films simultaneously, which were designated as P(NiPAAm-co-DMEM)-HRP. The films exhibited a reversible structure change with the external stimuli, such as pH, CO2, temperature and SO4(2-), causing the cyclic voltammetric (CV) response of electroactive K3Fe(CN)6 at the film electrodes to display the corresponding multi-stimuli sensitive ON-OFF behavior. Based on the switchable CV property of the system and the electrochemical reduction of H2O2 catalyzed by HRP in the films and mediated by Fe(CN)6(3-) in solution, a 5-input/3-output logic gate was established. To further increase the complexity of the logic system, another enzyme glucose oxidase (GOD) was added into the films, designated as P(NiPAAm-co-DMEM)-HRP-GOD. In the presence of oxygen, the oxidation of glucose in the solution was catalyzed by GOD in the films, and the produced H2O2 in situ was recognized and electrocatalytically reduced by HRP and mediated by Fe(CN)6(3-). Based on the bienzyme films, a cascaded or concatenated 4-input/3-output logic gate system was proposed. The present work combined the multi-responsive interface with bioelectrocatalysis to construct cascaded logic circuits, which might open a new avenue to develop biocomputing elements with more sophisticated functions and design novel glucose biosensors.

  7. Self-healing protective films prepared on zinc electrodes by treatment in a cerium(III) nitrate solution and modification with sodium phosphate and calcium or magnesium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Aramaki, Kunitsugu

    2003-10-01

    Self-healing protective films were prepared on a zinc electrode by treatment in a Ce(NO{sub 3}){sub 3} solution and modification with Na{sub 3}PO{sub 4} and Ca(NO{sub 3}){sub 2} or Mg(NO{sub 3}){sub 2}. The protective and self-healing abilities of the films were examined by polarization measurements and observation of pit formation after the electrode was scratched with a knife-edge and immersed in aerated 0.5 M NaCl for many hours. The protective efficiency of the film modified with Ca(NO{sub 3}){sub 2} was higher than that of the film without Ca(NO{sub 3}){sub 2} but the self-healing ability of the former film was not sufficiently high during the prolonged immersion. Mechanisms of the protective and self-healing activities were discussed using X-ray photoelectron spectroscopy and electron-probe microanalysis.

  8. Electrocatalytic oxidation and determination of dopamine at a carbon ionic liquid electrode modified with nafion-L-aspartic acid composite film

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The electrocatalytic oxidation of dopamine(DA)was studied by electrochemical approaches at a carbon ionic liquid electrode(CILE)modified with the composite film of nafion and L-aspartic acid(NL-CILE).The CILE was fabricated by replacing non-conductive organic binders with a room-temperature hydrophobic ionic liquid,1-butyl-3-methyl-imidazolium hexafluorophosphate.The composite film of NL was used as matrix to adsorb DA and catalyze the oxidation of DA in phosphate buffer solution(PBS).The electrochemical re...

  9. Dip-coated TiO2CeO2 films as transparent counter-electrode for transmissive electrochromic devices

    OpenAIRE

    Baudry, Paul; Rodrigues, A. C. M.; Michel A. Aegerter; Bulhoes, Luis O. S.

    1990-01-01

    The dip-coating process is an attractive way for the preparation of thin films used in the field of electrochromism. The scope of the present paper is focused on the TiO2CeO2 compounds since they exhibit a reversible electrochemical insertion of lithium ions maintaining a high optical transmissivity. These films can be used as transparent counter-electrode in an all solid state electrochromic transmissive device with, for example, WO3 as electrochromic material and a lithium conductive po...

  10. Effect of conductive BaPbO3 electrode on the structural and dielectric properties of (Pb,Ba)ZrO3 films

    Science.gov (United States)

    Wu, Lin-Jung; Wu, Jenn-Ming

    2007-08-01

    Highly (1 1 1)-oriented (Pb,Ba)ZrO3 (PBZ) thin films were deposited on BaPbO3(BPO) electrode at different deposition temperatures and different thicknesses. As the deposition temperature increased, the dielectric constant and tunability increased from 150 and 4% to 500 and 56%, respectively. A current transient peak observed prior to dielectric degradation can be related to oxygen vacancy migration (redistribution) with space-charge-limited current transient or modulation of the electric conductivity. We infer that an interfacial layer lying between the PBZ and BPO effectively increases the oxygen vacancy (density ~1020 cm-3) mobility by Pb4+ diffusing into the PBZ films.

  11. Electrodeposition of Silver Nanoparticles on MWCNT Film Electrodes for Hydrogen Peroxide Sensing

    Institute of Scientific and Technical Information of China (English)

    DING,Yan-Feng; JIN,Guan-Ping; YIN,Jun-Guang

    2007-01-01

    Silver (Ag) nanoparticles were directly electrodeposited on multi-walled carbon nanotubes (MWCNT) in AgNO3/LiNO3 containing EDTA (ethylenediaminetetraacetic acid). The structure and nature of the resulting Ag/MWNT composite were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), and the distribution shape of Ag nanoparticles was found to be dependent on the presence of EDTA. The modified electrode showed excellent electrocatalytic activity to redox reaction of hydrogen peroxide and the mechanism of hydrogen peroxide was partly reversible procession with oxidation and reduction peaks at 0.77 and -0.83 V, respectively. The oxidation and reduction peak currents were linearly related to hydrogen peroxide concentration in the range of 1×10-6-3×10-4 and 1×10-8-7×10-4 mol·L-1 with correlation coefficients of 0.996 and 0.986, and 3s-detection limit of 9 × 10-7 and 7 × 10-9 mol·L-1.

  12. Poly(brilliant green) and poly(thionine) modified carbon nanotube coated carbon film electrodes for glucose and uric acid biosensors.

    Science.gov (United States)

    Ghica, M Emilia; Brett, Christopher M A

    2014-12-01

    Poly(brilliant green) (PBG) and poly(thionine) (PTH) films have been formed on carbon film electrodes (CFEs) modified with carbon nanotubes (CNT) by electropolymerisation using potential cycling. Voltammetric and electrochemical impedance characterisation were performed. Glucose oxidase and uricase, as model enzymes, were immobilised on top of PBG/CNT/CFE and PTH/CNT/CFE for glucose and uric acid (UA) biosensing. Amperometric determination of glucose and UA was carried out in phosphate buffer pH 7.0 at -0.20 and +0.30 V vs. SCE, respectively, and the results were compared with other similarly modified electrodes existing in the literature. An interference study and recovery measurements in natural samples were successfully performed, indicating these architectures to be good and promising biosensor platforms. PMID:25159399

  13. Electrochemical properties of LiCoPO4-thin film electrodes in LiF-based electrolyte solution with anion receptors

    Science.gov (United States)

    Fukutsuka, Tomokazu; Nakagawa, Takuya; Miyazaki, Kohei; Abe, Takeshi

    2016-02-01

    Compatibility of LiF + anion receptors/propylene carbonate (PC) electrolyte solution with high potential positive electrode for lithium-ion batteries was examined by cyclic voltammetry. As anion receptors, tripropyl borate (TPB), tris(pentafluorophenyl) borane (TPFPB), and tris(hexafluoroisopropyl) borate (THFIPB) were used. LiCoPO4 thin-film electrodes were prepared by sol-gel method and used as both carbon- and binder-free model electrodes. From cyclic voltammograms, LiCoPO4 showed better cycleability in 0.1 mol dm-3 LiF + 0.1 mol dm-3 THFIPB/PC, however, other anion receptors did not give positive influence. It is indicated that the surface protecting layer from F--THFIPB complex and made LiCoPO4 stable. Electrochemical behavior depending on anion receptors was discussed according to reaction activity of F-.

  14. Bismuth subcarbonate as filler particle for an Epoxy-based root canal sealer

    Directory of Open Access Journals (Sweden)

    Eduardo Schwartzer

    2013-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the addition of bismuth subcarbonate with different concentrations regarding the rheological properties of an experimental epoxy-based root canal sealer. Materials and Methods: Endodontic sealers were prepared with epoxy resin-based sealer with bismuth subcarbonate additions of 20%, 40%, 60%, 80%, 100%, and 120%. Flow, film thickness, working time, setting time, dimensional change, sorption, solubility, and cytotoxicity were studied according to the ISO standards. Data were statistically analyzed by one-way ANOVA, and Tukey multiple comparisons were used, with a significance level of 5%. Results: The flow, working time, water sorption, and solubility significantly decreased and the film thickness and dimensional change increased with higher filler particle addition. There were no statistically significant differences for setting time and cytotoxicity between the filler particle proportions. Conclusion: Experimental resin-based sealer with bismuth subcarbonate addition up to 40% can be an alternative for root canal sealer.

  15. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

  16. Excimer laser deinsulation of Parylene-C on iridium for use in an activated iridium oxide film-coated Utah electrode array

    OpenAIRE

    Yoo, Je-Min; Negi, Sandeep; Tathireddy, Prashant; Solzbacher, Florian; Song, Jong-In; Rieth, Loren W

    2013-01-01

    Implantable microelectrodes provide a measure to electrically stimulate neurons in the brain and spinal cord and record their electrophysiological activity. A material with a high charge capacity such as activated or sputter-deposited iridium oxide film (AIROF or SIROF) is used as an interface. The Utah electrode array (UEA) uses SIROF for its interface material with neural tissue and oxygen plasma etching (OPE) with an aluminium foil mask to expose the active area, where the interface betwee...

  17. Enhanced direct electron transfer reactivity of hemoglobin in cationic gemini surfactant-room temperature ionic liquid composite film on glassy carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Li Jiangwen; Liu Lihong; Yan Rui; Xiao Mengying; Liu Liqin [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Zhao Faqiong [Department of Chemistry, Wuhan University, Wuhan 430072 (China)], E-mail: zhaofq@chem.edu.cn; Zeng Baizhao [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2008-05-20

    A novel composite film comprising cationic gemini surfactant butyl-{alpha},{omega}-bis(dimethylcetylammonium bromide) (C{sub 16}H{sub 33}N(CH{sub 3}){sub 2}-C{sub 4}H{sub 8}-N(CH{sub 3}){sub 2}C{sub 16}H{sub 33}, C{sub 16}-C{sub 4}-C{sub 16}) and ionic liquid 1-octyl-3-methylimidazolium hexafluorophate (OMIMPF{sub 6}) has been prepared. The composite film shows good biocompatibility and it can promote the direct electron transfer between hemoglobin (Hb) and glassy carbon (GC) electrode. On the C{sub 16}-C{sub 4}-C{sub 16} (dissolved in ethanol)-OMIMPF{sub 6} film coated GC electrode, the immobilized Hb can exhibit a pair of well-defined, quasi-reversible and stable redox peaks with a formal potential of -0.317 V (vs SCE) in 0.10 M pH 7 phosphate buffer solutions. The electron transfer coefficient ({alpha}) of Hb is calculated to be 0.44 and the heterogeneous electron transfer rate constant is 6.08 s{sup -1}. With the length of alkyl chains of gemini surfactant increasing and the ethanol concentration rising, the redox peaks of the resulting electrode C{sub 16}-C{sub 4}-C{sub 16}-OMIMPF{sub 6}-Hb/GC become bigger. The electrode presents good electrocatalytic response to peroxide hydrogen. The kinetic parameters I{sub max} and k{sub m} for the catalytic reaction are estimated. In addition, UV-vis spectra and reflectance absorption infrared spectra demonstrate that the Hb immobilized in the C{sub 16}-C{sub 4}-C{sub 16}-OMIMPF{sub 6} film almost retains the structure of native Hb.

  18. Layer-by-layer self-assembled multilayer films composed of graphene/polyaniline bilayers: high-energy electrode materials for supercapacitors.

    Science.gov (United States)

    Sarker, Ashis K; Hong, Jong-Dal

    2012-08-28

    Multilayer assemblies of uniform ultrathin film electrodes with good electrical conductivity and very large surface areas were prepared for use as electrochemical capacitors. A layer-by-layer self-assembly approach was employed in an effort to improve the processability of highly conducting polyaniline (PANi) and chemically modified graphene. The electrochemical properties of the multilayer film (MF-) electrodes, including the sheet resistance, volumetric capacitance, and charge/discharge ratio, were determined by the morphological modification and the method used to reduce the graphene oxide (GO) to reduced graphene oxide (RGO) in the multilayer films. The PANi and GO concentrations could be modulated to control the morphology of the GO monolayer film in the multilayer assemblies. Optical ellipsometry was used to determine the thickness of the GO film in a single layer (1.32 nm), which agreed well with the literature value (~1.3 nm). Hydroiodic acid (HI), hydrazine, or pyrolysis were tested for the reduction of GO to RGO. HI was found to be the most efficient technique for reducing the GO to RGO in the multilayer assemblies while minimizing damage to the virgin state of the acid-doped PANi. Ultimately, the MF-electrode, which could be optimized by fine-tuning the nanostructure and selecting a suitable reduction method, exhibited an excellent volumetric capacitance, good cycling stability, and a rapid charge/discharge rate, which are required for supercapacitors. A MF-electrode composed of 15 PANi/RGO bilayers yielded a volumetric capacitance of 584 F/cm(3) at a current density of 3.0 A/cm(3). Although this value decreased exponentially as the current density increased, approaching a value of 170 F/cm(3) at 100 A/cm(3), this volumetric capacitance is one of the best yet reported for the other carbon-based materials. The intriguing features of the MF-electrodes composed of PANi/RGO multilayer films offer a new microdimensional design for high energy storage devices

  19. Enzymatic glucose sensor based on Au nanoparticle and plant-like ZnO film modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Kun [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Alex, Saji [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Chemistry, Government College for Women, Thiruvananthapuram, Kerala 695014 (India); Siegel, Gene [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu [Nanostructured Materials Research Laboratory, Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

    2015-01-01

    A novel electrochemical glucose sensor was developed by employing a composite film of plant-like Zinc oxide (ZnO) and chitosan stabilized spherical gold nanoparticles (AuNPs) on which Glucose oxidaze (GOx) was immobilized. The ZnO was deposited on an indium tin oxide (ITO) coated glass and the AuNPs of average diameter of 23 nm were loaded on ZnO as the second layer. The prepared ITO/ZnO/AuNPs/GOx bioelectrode exhibited a low value of Michaelis–Menten constant of 1.70 mM indicating a good bio-matrix for GOx. The studies of electrochemical properties of the electrode using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed that, the presence of AuNPs provides significant enhancement of the electron transfer rate during redox reactions. The linear sweep voltammetry (LSV) shows that the ITO/ZnO/AuNPs/GOx based sensor has a high sensitivity of 3.12 μA·mM{sup −1}·cm{sup −2} in the range of 50 mg/dL to 400 mg/dL glucose concentration. The results show promising application of the gold nanoparticle modified plant-like ZnO composite bioelectrode for electrochemical sensing of glucose.

  20. Determination of Xanthine in the Presence of Hypoxanthine by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

    Science.gov (United States)

    Farias, Percio Augusto Mardini; Castro, Arnaldo Aguiar

    2014-01-01

    A stripping method for the determination of xanthine in the presence of hypoxanthine at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10−3 mol L−1 NaOH solution as supporting electrolyte, an accumulation potential of 0.00 V for xanthine and −0.50 V for hypoxanthine–copper, and a linear scan rate of 200 mV second−1. The response of xanthine is linear over the concentration ranges of 20–140 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 36 ppt (2.3 × 10−10 mol L−1). Adequate conditions for measuring the xanthine in the presence of hypoxanthine, copper and other metals, uric acid, and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of xanthine associated with hypoxanthine, uric acid, nitrogenated bases, ATP, and ssDNA. PMID:24940040

  1. ATR-SEIRAS study of CO adsorption and oxidation on Rh modified Au(111-25 nm) film electrodes in 0.1 M H2SO4

    International Nuclear Information System (INIS)

    Rh modified Au(111-25 nm) electrodes, prepared by electron beam evaporation and galvanostatic deposition, were employed to study adsorption and electro-oxidation of CO on Rh in 0.1 M sulfuric acid solution by in situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). The results of ATR-SEIRAS experiments were compared with those obtained by infrared reflection absorption spectroscopy on three low-index Rh single crystal surfaces. The Rh film deposited on Au(111-25 nm) electrode consists of 3D clusters forming a highly stepped [n(111) × (111)]-like surface with narrow (111) terraces. When CO was dosed at the hydrogen adsorption potential region, CO adsorbed in both atop (COL) and bridge (COB) configurations, as well as coadsorbed water species, were detected on the Rh film electrode. A partial interconversion of spectroscopic bands due to the CO displacement from bridge to atop sites was found during the anodic potential scan, revealing that there is a potential-dependent preference of CO adsorption sites on Rh surfaces. Our data indicate that CO oxidation on Rh electrode surface in acidic media involves coadsorbed water and follows the nucleation and growth model of a Langmuir-Hinshelwood type reaction

  2. Electrochemical reduction of 2,4-dinitrophenol on nanocomposite electrodes modified with mesoporous silica and poly(vitamin B{sub 1}) films

    Energy Technology Data Exchange (ETDEWEB)

    Yang Ping; Cai Hui; Liu Shantang [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073 (China); Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan 430073 (China); Hubei Key Lab of Novel Reactor and Green Chemical Technology, Wuhan 430073 (China); Wan Qijin, E-mail: qijinwan@mail.wit.edu.cn [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073 (China); Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan 430073 (China); Hubei Key Lab of Novel Reactor and Green Chemical Technology, Wuhan 430073 (China); Wang Xiaoxia [Blumenstrasse 6, Gundelfingen 79194 (Germany); Yang Nianjun, E-mail: nianjun.yang@iaf.fraunhofer.de [Fraunhofer-Institute for Applied Solid State Physics (IAF), Freiburg 79108 (Germany)

    2011-08-01

    Electrochemical reduction of 2,4-dinitrophenol was investigated on a glassy carbon electrode modified with a nanocomposite Santa Barbara Amorphous silica (SBA-15) film and poly(vitamin B{sub 1}) film. For sensitive and selective detections, vanadium pentoxide and cerium oxide nanoparticles were incorporated into the matrix of SBA-15. 2,4-Dinitrophenol was reduced on the modified electrode at -0.39 and -0.25 V, corresponding to the reduction of 4-dinitrophenol and 2-dinitrophenol, respectively. Both cathodic peak currents were controlled by the diffusion of 2,4-dinitrophenol. The amplitude of the peak currents was proportional to the 2,4-dinitrophenol concentration in the range of 3.0-30 {mu}M. The modified electrode demonstrated a long lifetime for the detection of 2,4-dinitrophenol. The detection limit of 2,4-dinitrophenol was 0.5 {mu}M. Moreover, the modified electrode was used successfully to detect 2,4-dinitrophenol in lake water.

  3. Comparative Study of Semiconductors Bismuth Iodate, Bismuth Triiodide and Bismuth Trisulphide Crystals

    Directory of Open Access Journals (Sweden)

    T.K. Patil

    2012-12-01

    Full Text Available In the present investigation, crystals of Bismuth Iodate[Bi(IO33], Bismuth Iodide[BiI3] and Bismuth- Tri Sulphide [Bi2S3] were grown by a simple gel technique using single diffusion method. The optimum growth conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of reactant etc. Gel was prepared by mixing sodium meta silicate (Na2SiO35H2O, glacial acetic acid (CH3COOH and supernant bismuth chloride (BiCl3 at pH value 4.4 and transferred in glass tube of diameter 2.5 cm and 25 cm in length. The mouth of test tube was covered by cotton plug and kept it for the setting. After setting the gel, it was left for aging. After 13 days duration the second supernant K(IO3, KI3 and H2S water gas solution was poured over the set gel by using pipette then it was kept undisturbed. After 72 hours of pouring the second supernatant, the small nucleation growth was observed at below the interface of gel. The good quality crystals of [Bi(IO33], [BiI3] and [Bi2S3] were grown. These grown crystals were characterized by XRD, FTIR, Chemical Analysis and Electrical Conductivity.

  4. Direct Electrochemistry of Glucose Oxidase Immobilized on Chitosan-gold Nanoparticle Composite Film on Glassy Carbon Electrodes and Its Biosensing Application

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The direct electrochemistry of glucose oxidase (Gox) immobilized on a composite matrix based on chitosan (CHIT) and Au nanoparticles (Au NP) underlying on a glassy carbon electrode was achieved. The cyclic voltam-metry and electrochemical impedance spectroscopy were used to characterize the modified electrode. In deaerated buffer solutions, the cyclic voltammetry of the composite films of Gox-Au NP-CHIT showed a pair of well-behaved redox peaks that were assigned to the redox reaction of Gox, confirming the effective immobilization of Gox on the composite film. The electron transfer rate constant was estimated to be 15.6 s-1, indicating a high electron transfer between the Gox redox center and electrode. The combination of CHIT and Au NP also promoted the stability of Gox in the composite film and retained its bioactivity, which might have the potential application to glucose determination. The calculated apparent Michaelis-Menten constant was 10.1 mmol·L-1. Furthermore, the proposed biosensor could be used for the determination of glucose in human plasma samples.

  5. A layer-by-layer assembled graphene/zinc sulfide/polypyrrole thin-film electrode via electrophoretic deposition for solar cells

    International Nuclear Information System (INIS)

    An organic–inorganic photovoltaic electrode consisting of graphene nanosheets, zinc sulfide nanoparticles (ZnS) and polypyrrole nanotubes (PPy) was fabricated on indium tin oxide (ITO) glass using layer-by-layer electrophoretic deposition. The morphology and structure of the as-fabricated electrode were confirmed by X-ray diffraction, high resolution transmission electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. The photovoltaic properties of the ZnS, ZnS/PPy (ZP) and graphene/ZnS/PPy (GZP) ternary composite films modified on ITO electrodes were investigated for their solar cell performance. Both transient photocurrent and current–voltage curve measurements illustrated that the photocurrent and the power conversion efficiency of the GZP ternary composite film were significantly enhanced compared to the ZnS and ZP films. Based on these results, PPy nanotubes are an excellent sensitizer and hole acceptor, ZnS nanoparticles act as a bridge and graphene nanosheets are an excellent conductive collector and transporter, which means that, altogether, this combination of materials can significantly increase the photovoltaic efficiency. - Highlights: • Zinc sulfide (ZnS)/polypyrrole(PPy)/graphene by electrophoretic deposition • Support of ZnS/PPy composite shows efficient performance of organic–inorganic solar cell. • Current–voltage curve and transient current improved in the presence of graphene

  6. Direct electrochemistry of myoglobin in a layer-by-layer film on an ionic liquid modified electrode containing CeO2 nanoparticles and hyaluronic acid

    International Nuclear Information System (INIS)

    We describe an ionic liquid modified electrode (CPE-IL) for sensing hydrogen peroxide (HP) that was modified by the layer-by-layer technique with myoglobin (Mb). In addition, the surface of the electrode was modified with CeO2 nanoparticles (nano-CeO2) and hyaluronic acid. UV-vis and FTIR spectroscopy confirmed that Mb retains its native structure in the composite film. Scanning electron microscopy showed that the nano-CeO2 closely interact with Mb to form an inhomogeneously distributed film. Cyclic voltammetry reveals a pair of quasi-reversible redox peaks of Mb, with the cathodic peak at -0. 357 V and the anodic peak at -0. 269 V. The peak separation (ΔEp) and the formal potential (Eσ) are 88 mV and -0. 313 V (vs. Ag/AgCl), respectively. The Mb immobilized in the modified electrode displays an excellent electrocatalytic activity towards HP in the 0. 6 to 78. 0 μM concentration range. The limit of detection is 50 nM (S/N = 3), and then the Michaelis-Menten constant is 71. 8 μM. We believe that such a composite film has potential to further investigate other redox proteins and in the fabrication of third-generation biosensors. (author)

  7. An artificial photosynthesis anode electrode composed of a nanoparticulate photocatalyst film in a visible light responsive GaN-ZnO solid solution system

    Science.gov (United States)

    Imanaka, Yoshihiko; Anazawa, Toshihisa; Manabe, Toshio; Amada, Hideyuki; Ido, Sachio; Kumasaka, Fumiaki; Awaji, Naoki; Sánchez-Santolino, Gabriel; Ishikawa, Ryo; Ikuhara, Yuichi

    2016-01-01

    The artificial photosynthesis technology known as the Honda-Fujishima effect, which produces oxygen and hydrogen or organic energy from sunlight, water, and carbon dioxide, is an effective energy and environmental technology. The key component for the higher efficiency of this reaction system is the anode electrode, generally composed of a photocatalyst formed on a glass substrate from electrically conductive fluorine-doped tin oxide (FTO). To obtain a highly efficient electrode, a dense film composed of a nanoparticulate visible light responsive photocatalyst that usually has a complicated multi-element composition needs to be deposited and adhered onto the FTO. In this study, we discovered a method for controlling the electronic structure of a film by controlling the aerosol-type nanoparticle deposition (NPD) condition and thereby forming films of materials with a band gap smaller than that of the prepared raw material powder, and we succeeded in extracting a higher current from the anode electrode. As a result, we confirmed that a current approximately 100 times larger than those produced by conventional processes could be obtained using the same material. This effect can be expected not only from the materials discussed (GaN-ZnO) in this paper but also from any photocatalyst, particularly materials of solid solution compositions. PMID:27759108

  8. Influence of Nafion film on oxygen reduction reaction and hydrogen peroxide formation on Pt electrode for proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    The influence of Nafion film on ORR kinetics and H2O2 formation on a Pt electrode was investigated using RRDE in 0.1 M HClO4. It was found that the Nafion-coated Pt system showed lower apparent ORR activity and more H2O2 production than the bare Pt electrode system. From the temperature sensitivity, it was revealed that the apparent activation energies of ORR in the Nafion-coated Pt system were lower than the bare Pt electrode system, and the H2O2 formation was suppressed with the increase of the temperature. In order to analyze the results furthermore, other systems (0.1/1.0 M, HClO4/CF3SO3H) with the bare Pt electrodes were also examined as references. It was exhibited that the ORR kinetic current, the H2O2 formation, and the apparent activation energies of 1.0 M CF3SO3H system were close to those of the Nafion-coated Pt system. We concluded that the orientation of anion species of Nafion and CF3SO3H to the Pt surface via water molecules, as well as a fluorocarbon polymer network of Nafion, might block O2 adsorption, resulting in the smaller effective surface area of the Pt electrode for ORR, the smaller ORR kinetic current, and the more H2O2 production.

  9. Electrochemical and Spectroscopic Analysis of Mg2+ Intercalation into Thin Film Electrodes of Layered Oxides: V2O5 and MoO3

    Energy Technology Data Exchange (ETDEWEB)

    Gershinsky, G; Yoo, HD; Gofer, Y; Aurbach, D

    2013-08-27

    Electrochemical, surface, and structural studies related to rechargeable Mg batteries were carried out with monolithic thin-film cathodes comprising layered V2O5 and MoO3. The reversible intercalation reactions of these electrodes with Mg ion in nonaqueous Mg salt solutions were explored using a variety of analytical tools. These included slow-scan rate cyclic voltammetry (SSCV), chrono-potentiometry (galvanostatic cycling), Raman and photoelectron spectroscopies, high-resolution microscopy, and XRD. The V2O5 electrodes exhibited reversible Mg-ion intercalation at capacities around 150-180 mAh g(-1) with 100% efficiency. A capacity of 220 mAh g(-1) at >95% efficiency was obtained with MoO3 electrodes. By applying the electrochemical driving force sufficiently slowly it was possible to measure the electrodes at equilibrium conditions and verify by spectroscopy, microscopy, and diffractometry that these electrodes undergo fully reversible structural changes upon Mg-ion insertion/deinsertion cycling.

  10. ITO-Free Semitransparent Organic Solar Cells Based on Silver Thin Film Electrodes

    Directory of Open Access Journals (Sweden)

    Zhizhe Wang

    2014-01-01

    Full Text Available ITO-free semitransparent organic solar cells (OSCs based on MoO3/Ag anodes with poly(3-hexylthiophene and [6,6]-phenyl-C61-butyric acid methyl ester films as the active layer are investigated in this work. To obtain the optimal transparent (MoO3/Ag anode, ITO-free reference OSCs are firstly fabricated. The power conversion efficiency (PCE of 2.71% is obtained for OSCs based on the optimal MoO3 (2 nm/Ag (9 nm anode, comparable to that of ITO-based reference OSCs (PCE of 2.85%. Then based on MoO3 (2 nm/Ag (9 nm anode, ITO-free semitransparent OSCs with different thickness combination of Ca and Ag as the cathodes are investigated. It is observed from our results that OSCs with Ca (15 nm/Ag (15 nm cathode have the optimal transparency. Meanwhile, the PCE of 1.79% and 0.67% is obtained for illumination from the anode and cathode side, respectively, comparable to that of similar ITO-based semitransparent OSCs (PCE of 1.59% and 0.75% for illumination from the anode and cathode side, resp. (Sol. Energy Mater. Sol. Cells, 95, pp. 877–880, 2011. The transparency and PCE of ITO-free semitransparent OSCs can be further improved by introducing a light couple layer. The developed method is compatible with various substrates, which is instructive for further research of ITO-free semitransparent OSCs.

  11. Photoelectrocatalytic oxidation of GMP on an ITO electrode modified with clay/[Ru(phen)2(dC18bpy)]2+ hybrid film

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An indium tin oxide (ITO) electrode modified with monolayer clay/[Ru(phen)2(dC18bpy)]2+ (phen= 1,10-phenanthroline, dC18bpy = 4,4′-dioctadecyl-2,2′ bipyridyl) hybrid film has been fabricated by the Langmuir-Blodgett (LB) method. Atomic force microscopy revealed that the single-layered hybrid film of clay/[Ru(phen)2(dC18bpy)]2+ (denoted as Clay-Ru) was closely packed at a surface pressure of 25 mN-m-1 and had a thickness of 3.4±0.5 nm. Cyclic voltammograms showed that the redox current of Ru(Ⅱ) complex decreased when incorporated into the clay film, suggesting that the clay layer acts as a barrier against electron transfer. When applied to oxidizing the mononucleotide of guanosine 5′-monophosphate (GMP), a large catalytic oxidative current was achieved on the Clay-Ru(Ⅱ) modified ITO electrode at the external potential above 900 mV (vs. Ag|AgCl|KCl ) and, more significantly, this response was further enhanced by light irradiation (λ>360 nm), in which the photocurrent is increased about 11 times in comparison with that of a bare ITO. Mechanism of the photoelectrocatalytic effect was proposed in terms of the reduction of the photoelectrochemically generated Ru(Ⅲ) complex in the Clay-Ru film by GMP.

  12. Photoelectrocatalytic oxidation of GMP on an ITO electrode modified with clay/[Ru(phen)2(dC 18bpy)]2+hybrid film

    Institute of Scientific and Technical Information of China (English)

    CHANG Xue-Qin; WANG Shun; LIN Da-Jie; GUAN Wei-Peng; ZHOU Huan; HUANG Shao-Ming

    2009-01-01

    An indium tin oxide (ITO) electrode modified with monolayer clay/[Ru(phen)2(dC18bpy)]2+ (phen= 1,10-phenanthroline, dC18bpy = 4,4'-dioctsdecyl-2,2' bipyridyl) hybrid film has been fabricated by the Langmuir-Blodgett (LB) method. Atomic force microscopy revealed that the single-layered hybrid film of clay/[Ru(phen)2(dC18bpy)]2+. (denoted as Clay-Ru) was closely packed at a surface pressure of 25 Ru(Ⅱ) complex decreased when incorporated into the clay film, suggesting that the clay layer acts as a barrier against electron transfer. When applied to oxidizing the mononucleotide of guanosine 5'-monophosphate (GMP), a large catalytic oxidative current was achieved on the Clay-Ru(Ⅱ) modified ITO electrode at the external potential above 900 mV (vs. AglAgCIlKCI) and, more significantly, this response was further enhanced by light irradiation (λ360 nm), in which the photocurrent is increased about 11 times in comparison with that of a bare ITO. Mechanism of the photoelectrocatalytic effect was proposed in terms of the reduction of the photoelectrochemically generated Ru(Ⅲ) complex in the Clay-Ru film by GMP.

  13. Accurate and representative decoding of the neural drive to muscles in humans with multi-channel intramuscular thin-film electrodes.

    Science.gov (United States)

    Muceli, Silvia; Poppendieck, Wigand; Negro, Francesco; Yoshida, Ken; Hoffmann, Klaus P; Butler, Jane E; Gandevia, Simon C; Farina, Dario

    2015-09-01

    Intramuscular electrodes developed over the past 80 years can record the concurrent activity of only a few motor units active during a muscle contraction. We designed, produced and tested a novel multi-channel intramuscular wire electrode that allows in vivo concurrent recordings of a substantially greater number of motor units than with conventional methods. The electrode has been extensively tested in deep and superficial human muscles. The performed tests indicate the applicability of the proposed technology in a variety of conditions. The electrode represents an important novel technology that opens new avenues in the study of the neural control of muscles in humans. We describe the design, fabrication and testing of a novel multi-channel thin-film electrode for detection of the output of motoneurones in vivo and in humans, through muscle signals. The structure includes a linear array of 16 detection sites that can sample intramuscular electromyographic activity from the entire muscle cross-section. The structure was tested in two superficial muscles (the abductor digiti minimi (ADM) and the tibialis anterior (TA)) and a deep muscle (the genioglossus (GG)) during contractions at various forces. Moreover, surface electromyogram (EMG) signals were concurrently detected from the TA muscle with a grid of 64 electrodes. Surface and intramuscular signals were decomposed into the constituent motor unit (MU) action potential trains. With the intramuscular electrode, up to 31 MUs were identified from the ADM muscle during an isometric contraction at 15% of the maximal force (MVC) and 50 MUs were identified for a 30% MVC contraction of TA. The new electrode detects different sources from a surface EMG system, as only one MU spike train was found to be common in the decomposition of the intramuscular and surface signals acquired from the TA. The system also allowed access to the GG muscle, which cannot be analysed with surface EMG, with successful identification of MU

  14. Fabrication of a porous Pd film on nanoporous stainless steel using galvanic replacement as a novel electrocatalyst/electrode design for glycerol oxidation

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Nanopore arrays were formed on stainless steel surface substrate using anodization. • Cu electrodeposited into the nanopores was spontaneously replaced with Pd. • The electrode showed a remarkable catalytic activity for glycerol electrooxidation. • Cu improves the reaction kinetics and increases the catalytic activity of the Pd. - Abstract: In this work, nanoporous stainless steel (NPSS) prepared by anodization process was used as an electrode material to support noble metal-based catalysts. To decorate NPSS with Pd, copper was deposited into the pores of NPSS using pulsed electrodeposition, and followed by the galvanic replacement reaction between deposited Cu and PdCl2 solution. The surface morphology and composition of the prepared electrode were determined using scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray spectroscopy (EDS). SEM and AFM images showed that self-organized nanopores with an average size of about 77 nm were formed on the stainless steel surface and then were successfully filled with Cu. Galvanic replacement resulted in the formation of a porous film with a high electrochemically active surface area (EASA = 173.4 cm2 mg−1) and greatly reducing Pd loading (29 μg cm−2). The EDS analysis revealed the presence of Cu and Pd in the prepared electrode (NPSS/Cu/Pd). Cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques were used to investigate the electrochemical behavior of the NPSS/Cu/Pd electrode in alkaline media. It was found that the porosity of NPSS and the presence of Cu improve the long-term stability of the Pd film on the surface. The electrode exhibited a remarkable catalytic activity for electrooxidation of glycerol due to the large EASA. The obtained mass activity and onset potential for glycerol oxidation were 0.82 mA μgPd−1 and −0.35 V, respectively, which are acceptable as compared with those of

  15. Tunnel magnetoresistance in full-epitaxial magnetic tunnel junctions with a top electrode consisting of a perpendicularly magnetized D022-Mn3Ge film

    Science.gov (United States)

    Sugihara, Atsushi; Suzuki, Kazuya; Miyazaki, Terunobu; Mizukami, Shigemi

    2015-07-01

    We grew a magnetic tunnel junction (MTJ) with a top electrode consisting of a Mn3Ge film using a thin Co-Fe alloy film as a seed layer. X-ray diffraction showed that the Mn3Ge had (001)-oriented D022 structure epitaxially grown on an MgO(001) substrate. Magnetic hysteresis loops suggested that the D022-Mn3Ge film possessed perpendicular magnetic anisotropy. A magnetoresistance (MR) ratio of 11.3% was observed in the microfabricated MTJ at room temperature. The resistance-field curve suggested that the top-Co-Fe and D022-Mn3Ge layer are weakly coupled antiferromagnetically. The optimization of top-Co-Fe composition would improve MR ratio.

  16. Highly sensitive and multifunctional tactile sensor using free-standing ZnO/PVDF thin film with graphene electrodes for pressure and temperature monitoring.

    Science.gov (United States)

    Lee, James S; Shin, Keun-Young; Cheong, Oug Jae; Kim, Jae Hyun; Jang, Jyongsik

    2015-01-20

    We demonstrate an 80-μm-thick film (which is around 15% of the thickness of the human epidermis), which is a highly sensitive hybrid functional gauge sensor, and was fabricated from poly(vinylidene fluoride) (PVDF) and ZnO nanostructures with graphene electrodes. Using this film, we were able to simultaneously measure pressure and temperature in real time. The pressure was monitored from the change in the electrical resistance via the piezoresistance of the material, and the temperature was inferred based on the recovery time of the signal. Our thin film system enabled us to detect changes in pressure as small as 10 Pa which is pressure detection limit was 10(3)-fold lower than the minimum level required for artificial skin, and to detect temperatures in the range 20-120 °C.

  17. Impedance spectroscopic investigation of the effect of thin azo-calix[4]arene film type on the cation sensitivity of the gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Mlika, R., E-mail: mlikarym@yahoo.fr [Laboratoire de Physique et Chimie des Interfaces (LPCI), Faculte des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Rouis, A. [Laboratoire de Physique et Chimie des Interfaces (LPCI), Faculte des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Bonnamour, I. [Universite de Lyon, Institut de Chimie et Biochimie Moleculaires et Supramoleculaires, Universite Claude Bernar, Lyon 1, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne (France); Ouada, H. Ben [Laboratoire de Physique et Chimie des Interfaces (LPCI), Faculte des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia)

    2011-10-10

    In this work, we report the impedance spectroscopic investigation of the effect of the thin film type on the selectivity of gold/azo-calix[4]arene electrodes. For this purpose, two C1 and C3 azo-calix[4]arene derivative molecules, used as thin films, are deposited by spin-coating process on the gold surface. These thin films were first studied using contact angle measurements. This revealed a less hydrophobic character for C3 thin film, which has been attributed to the presence of hydroxyl groups at the lower rim. The sensitivity study, by Electrochemical Impedance Spectroscopy (EIS), towards Cu{sup 2+} and Eu{sup 3+} cations, has showed that the C3 thin film is more sensitive and selective towards Eu{sup 3+} than C1. This best performance is due to the presence of two ester groups acting as clips and leading to more complexation stability. The EIS results were modeled by an appropriate equivalent circuit for the aim of elucidating electrical properties of thin films. This modeling has exposed that C3 thin film presents lower ionic conductivity and limited diffusion phenomenon at the interface. Highlights: {yields} C1 and C3 azo-calix[4]arenes thin films are deposited on the gold surface. {yields} The lower hydrophobicity for C3 was attributed to the presence of hydroxyl groups. {yields} The C3 thin film is more sensitive and selective towards Eu{sup 3+} than C1 one. {yields} This best performance is due to the presence of two ester groups acting as clips.

  18. Structure and electrical properties of Al-doped HfO₂ and ZrO₂ films grown via atomic layer deposition on Mo electrodes.

    Science.gov (United States)

    Yoo, Yeon Woo; Jeon, Woojin; Lee, Woongkyu; An, Cheol Hyun; Kim, Seong Keun; Hwang, Cheol Seong

    2014-12-24

    The effects of Al doping in atomic-layer-deposited HfO2 (AHO) and ZrO2 (AZO) films on the evolutions of their crystallographic phases, grain sizes, and electric properties, such as their dielectric constants and leakage current densities, were examined for their applications in high-voltage devices. The film thickness and Al-doping concentration were varied in the ranges of 60-75 nm and 0.5-9.7%, respectively, for AHO and 55-90 nm and 1.0-10.3%, respectively, for AZO. The top and bottom electrodes were sputtered Mo films. The detailed structural and electrical property variations were examined as functions of the Al concentration and film thickness. The AHO films showed a transition from the monoclinic phase (Al concentration up to 1.4%) to the tetragonal/cubic phase (Al concentration 2.0-3.5%), and finally, to the amorphous phase (Al concentration >4.7%), whereas the AZO films remained in the tetragonal/cubic phase up to the Al concentration of 6.4%. For both the AHO and AZO films, the monoclinic and amorphous phases had dielectric constants of 20-25, and the tetragonal/cubic phases had dielectric constants of 30-35. The highest electrical performance levels for the application to the high-voltage charge storage capacitors in flat panel displays were achieved with the 4.7-9.7% Al-doped AHO films and the 2.6% Al-doped AZO films. PMID:25423483

  19. Structure of unsupported bismuth nanoparticles

    Science.gov (United States)

    Wurl, A.; Hyslop, M.; Brown, S. A.; Hall, B. D.; Monot, R.

    We present new results of electron diffraction experiments on unsupported nanometer-sized bismuth clusters. The high intensity cluster beam, necessary for electron diffraction, is provided by an inert-gas aggregation source. The cluster beam contains particles with average cluster sizes between 4.5 and 10 nm. When using Helium as a carrier gas we are able to observe a transition from crystalline clusters to a new structure, which we identify with that of amorphous or liquid clusters.

  20. Spray deposited copper zinc tin sulphide (Cu2ZnSnS4) film as a counter electrode in dye sensitized solar cells.

    Science.gov (United States)

    Swami, Sanjay Kumar; Chaturvedi, Neha; Kumar, Anuj; Chander, Nikhil; Dutta, Viresh; Kumar, D Kishore; Ivaturi, A; Senthilarasu, S; Upadhyaya, Hari M

    2014-11-21

    Stoichiometric thin films of Cu2ZnSnS4 (CZTS) were deposited by the spray technique on a FTO coated glass substrate, with post-annealing in a H2S environment to improve the film properties. CZTS films were used as a counter electrode (CE) in Dye-Sensitized Solar Cells (DSCs) with N719 dye and an iodine electrolyte. The DSC of 0.25 cm(2) area using a CE of CZTS film annealed in a H2S environment under AM 1.5G illumination (100 mW cm(-2)) exhibited a short circuit current density (JSC) = 18.63 mA cm(-2), an open circuit voltage (VOC) = 0.65 V and a fill factor (FF) = 0.53, resulting in an overall power conversion efficiency (PCE) = 6.4%. While the DSC using as deposited CZTS film as a CE showed the PCE = 3.7% with JSC = 13.38 mA cm(-2), VOC = 0.57 V and FF = 0.48. Thus, the spray deposited CZTS films can play an important role as a CE in the large area DSC fabrication. PMID:25286339

  1. Study on the fabrication of transparent electrodes by using a thermal-roll imprinted Ag mesh and anATO thin film

    Science.gov (United States)

    Kim, Sung Jin; Choi, Kyoon; Choi, Se Young

    2016-03-01

    Transparent conductive films have been widely studied because of their potential applications in optoelectronic devices such as paper displays, dye-sensitized solar cells (DSSCs), organic lighting-emitting diodes (OLEDs), organic solar cells and so on. In this paper, we report on a low-resistance, a high-transparents conductive film that can be applied as It a flexible device substrate. In order to the fabricate transparent conductive film, we used a high-resolution roll imprinting method. The following steps were performed: The design and manufacture of an electroforming stamp mold, the fabrication of high resolution roll imprinted on flexible film, and the manufacture of an Ag grid that was filled by using a doctor blade process with a nano-sized Ag paste. Then on patterned Its films, antimony tin oxide was coated with ATO sol solution by using bar the coating method. The fabricated ATO/Ag mesh electrode showed good flexibility, and It exhibited a high optical transmittance of 85.3% in the visible wavelength and a sheet resistance of 41 Ω/sq. Furthermore, the bending test for mechanical properties showed that the ATO/Ag thin film had good flexibility.

  2. Synthesis and Characterization of Self-Standing and Highly Flexible δ-MnO2@CNTs/CNTs Composite Films for Direct Use of Supercapacitor Electrodes.

    Science.gov (United States)

    Wu, Peng; Cheng, Shuang; Yang, Lufeng; Lin, Zhiqiang; Gui, Xuchun; Ou, Xing; Zhou, Jun; Yao, Minghai; Wang, Mengkun; Zhu, Yuanyuan; Liu, Meilin

    2016-09-14

    Self-standing and flexible films worked as pseudocapacitor electrodes have been fabricated via a simple vacuum-filtration procedure to stack δ-MnO2@carbon nanotubes (CNTs) composite layer and pure CNT layer one by one with CNT layers ended. The lightweight CNTs layers served as both current collector and supporter, while the MnO2@CNTs composite layers with birnessite-type MnO2 worked as active layer and made the main contribution to the capacitance. At a low discharge current of 0.2 A g(-1), the layered films displayed a high areal capacitance of 0.293 F cm(-2) with a mass of 1.97 mg cm(-2) (specific capacitance of 149 F g(-1)) and thickness of only 16.5 μm, and hence an volumetric capacitance of about 177.5 F cm(-3). Moreover, the films also exhibited a good rate capability (only about 15% fading for the capacitance when the discharge current increased to 5 A g(-1) from 0.2 A g(-1)), outstanding cycling stability (about 90% of the initial capacitance was remained after 5,000 cycles) and high flexibility (almost no performance change when bended to different angles). In addition, the capacitance of the films increased proportionally with the stacked layers and the geometry area. E.g., when the stacked layers were three times many with a mass of 6.18 mg cm(-2), the areal capacitance of the films was increased to 0.764 F cm(-2) at 0.5 A g(-1), indicating a high electronic conductivity. It is not overstated to say that the flexible and lightweight layered films emerged high potential for future practical applications as supercapacitor electrodes. PMID:27561652

  3. Ranitidine bismuth citrate: A review

    Directory of Open Access Journals (Sweden)

    N Chiba

    2001-01-01

    Full Text Available Recognition of the relationship between Helicobacter pylori infection and the development of gastroduodenal disease has increased greatly in recent years. To avoid complications of H pylori infection, such as the development of recurrent duodenal and gastric ulcers, effective therapies are required for eradication of the infection. This article reviews ranitidine bismuth citrate (RBC, a novel complex of ranitidine, bismuth and citrate, which was developed specifically for the purpose of eradicating H pylori. Dual therapy with RBC in combination with clarithromycin for 14 days yields eradication rates of 76%. Triple therapy bid for one week with a proton pump inhibitor, clarithromycin and either amoxicillin or a nitroimidazole (tinidazole or metronidazole is advocated as the treatment of choice for H pylori eradication. Analogous regimens with RBC in place of proton pump inhibitors show effective eradication rates in comparative studies and with pooled data. RBC, used alone or in combination with other antibiotics, appears to be a safe and effective drug for the treatment of H pylori infection. Bismuth levels do not appear to rise to toxic levels.

  4. Bridge-bonded formate: active intermediate or spectator species in formic acid oxidation on a Pt film electrode?

    Science.gov (United States)

    Chen, Y-X; Heinen, M; Jusys, Z; Behm, R J

    2006-12-01

    We present and discuss the results of an in situ IR study on the mechanism and kinetics of formic acid oxidation on a Pt film/Si electrode, performed in an attenuated total reflection (ATR) flow cell configuration under controlled mass transport conditions, which specifically aimed at elucidating the role of the adsorbed bridge-bonded formates in this reaction. Potentiodynamic measurements show a complex interplay between formation and desorption/oxidation of COad and formate species and the total Faradaic current. The notably faster increase of the Faradaic current compared to the coverage of bridge-bonded formate in transient measurements at constant potential, but with different formic acid concentrations, reveals that adsorbed formate decomposition is not rate-limiting in the dominant reaction pathway. If being reactive intermediate at all, the contribution of formate adsorption/decomposition to the reaction current decreases with increasing formic acid concentration, accounting for at most 15% for 0.2 M DCOOH at 0.7 VRHE. The rapid build-up/removal of the formate adlayer and its similarity with acetate or (bi-)sulfate adsorption/desorption indicate that the formate adlayer coverage is dominated by a fast dynamic adsorption-desorption equilibrium with the electrolyte, and that formate desorption is much faster than its decomposition. The results corroborate the proposal of a triple pathway reaction mechanism including an indirect pathway, a formate pathway, and a dominant direct pathway, as presented previously (Chen, Y. X.; et al. Angew. Chem. Int. Ed. 2006, 45, 981), in which adsorbed formates act as a site-blocking spectator in the dominant pathway rather than as an active intermediate.

  5. Electrochemical deposition of molybdenum sulfide thin films on conductive plastic substrates as platinum-free flexible counter electrodes for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chao-Kuang; Hsieh, Chien-Kuo, E-mail: jack_hsieh@mail.mcut.edu.tw

    2015-06-01

    In this study, pulsed electrochemical deposition (pulsed ECD) was used to deposit molybdenum sulfide (MoS{sub x}) thin films on indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as flexible counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The surface morphologies and elemental distributions of the prepared MoS{sub x} thin films were examined using field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy. The chemical states and crystallinities of the prepared MoS{sub x} thin films were examined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The optical transmission (T (%)) properties of the prepared MoS{sub x} samples were determined by ultraviolet–visible spectrophotometry. Cyclic voltammetry (CV) and Tafel-polarization measurements were performed to analyze the electrochemical properties and catalytic activities of the thin films for redox reactions. The FE-SEM results showed that the MoS{sub x} thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulsed ECD method. The CV and Tafel-polarization curve measurements demonstrated that the deposited MoS{sub x} thin films exhibited excellent performances for the reduction of triiodide ions. The photoelectric conversion efficiency (PCE) of the DSSC produced with the pulsed ECD MoS{sub x} thin-film CE was examined by a solar simulator. In combination with a dye-sensitized TiO{sub 2} working electrode and an iodine-based electrolyte, the DSSC with the MoS{sub x} flexible CE showed a PCE of 4.39% under an illumination of AM 1.5 (100 mW cm{sup −2}). Thus, we report that the MoS{sub x} thin films are active catalysts for triiodide reduction. The MoS{sub x} thin films are prepared at room temperature and atmospheric pressure and in a simple and rapid manner. This is an important practical contribution to the production of flexible low-cost thin-film CEs based on plastic substrates. The MoS{sub x

  6. Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wencai [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan 250013 (China); Huang, Hui; Gao, Xiaochun [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Ma, Houyi, E-mail: hyma@sdu.edu.cn [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2014-12-01

    Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1–65 μM with a low detection limit of 0.01 μM (S/N = 3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets. - Highlights: • The 4-ABA/ERGO/GCE was fabricated by a two-step electrochemical method. • Electrochemical behavior of acetaminophen at the 4-ABA/ERGO/GCE was investigated. • The electrochemical sensor exhibited a low detection limit and good selectivity. • This sensor was applied to the detection of acetaminophen in commercial tablets.

  7. Construction of Amperometric Glucose Biosensor based onIn-situ Fabricated Hierarchical Meso-macroporous SiO2 Modiifed AuFilm Electrodes

    Institute of Scientific and Technical Information of China (English)

    TANG Min; LIN Xinhua; LI Maoguo; LI Jie; NI Lin; YIN Shiping

    2016-01-01

    Gold nanoparticles (GNPs) modified hierarchical meso-macroporous (HMMP) SiO2 layer on the surface of Au iflm electrode was developed as a novel enzyme immobilization matrix for biosensors construction. HMMP SiO2-Au bilayer film electrodes were in-situ fabricated with magnetron sputtering process and templating method. The as-prepared HMMP SiO2 films were characterized by SEM, TEM, and cyclic voltammetry (CV). The modiifed layer of HMMP SiO2 has interconnected pore channels, and the sizes of macropores and mesopores are about 330 nm and 9 nm, respectively. The HMMP SiO2 modiifed gold iflm electrodes not only have no diffusion barrier for electrochemical probes, but also exhibit good electrochemical properties. In addition, the activity and stability of the immobilized enzyme can be commendably retained in HMMP SiO2. The biosensor exhibits an excellent bioelectrocatalytic response to glucose with a linear range of 1.0×10-4 M-1.0×10-2 M, high sensitivity of 18.0 μA·mM-1·cm-2, as well as good reproducibility and stability.

  8. In vitro cytotoxicity of surface modified bismuth nanoparticles.

    Science.gov (United States)

    Luo, Yang; Wang, Chaoming; Qiao, Yong; Hossain, Mainul; Ma, Liyuan; Su, Ming

    2012-10-01

    This paper describes in vitro cytotoxicity of bismuth nanoparticles revealed by three complementary assays (MTT, G6PD, and calcein AM/EthD-1). The results show that bismuth nanoparticles are more toxic than most previously reported bismuth compounds. Concentration dependent cytotoxicities have been observed for bismuth nanoparticles and surface modified bismuth nanoparticles. The bismuth nanoparticles are non-toxic at concentration of 0.5 nM. Nanoparticles at high concentration (50 nM) kill 45, 52, 41, 34 % HeLa cells for bare nanoparticles, amine terminated bismuth nanoparticles, silica coated bismuth nanoparticles, and polyethylene glycol (PEG) modified bismuth nanoparticles, respectively; which indicates cytotoxicity in terms of cell viability is in the descending order of amine terminated bismuth nanoparticles, bare bismuth nanoparticles, silica coated bismuth nanoparticles, and PEG modified bismuth nanoparticles. HeLa cells are more susceptible to toxicity from bismuth nanoparticles than MG-63 cells. The simultaneous use of three toxicity assays provides information on how nanoparticles interact with cells. Silica coated bismuth nanoparticles can damage cellular membrane yet keep mitochondria less influenced; while amine terminated bismuth nanoparticles can affect the metabolic functions of cells. The findings have important implications for caution of nanoparticle exposure and evaluating toxicity of bismuth nanoparticles.

  9. Glucose sensor based on an electrochemical reduced graphene oxide-poly(L-lysine) composite film modified GC electrode.

    Science.gov (United States)

    Hua, Liang; Wu, Xiaqin; Wang, Rong

    2012-12-21

    A convenient and environmentally friendly method of fabricating glucose biosensors is proposed. Glucose oxidase (GOD) was immobilized on electrochemically reduced graphene oxide (ERGO) which was adsorbed on the poly-L-lysine (PLL) modified glassy carbon electrode after being immersed in GO solution for 4 h. The electrochemical behaviors of GOD/ERGO/PLL/GC electrode have been investigated by cyclic voltammetry. Direct electron transfer between GOD immobilized with ERGO/PLL and GC electrode was observed. Moreover, the GOD/ERGO/PLL/GC electrode exhibited excellent electrocatalytic activity for the detection of glucose with a linear range from 0.25 to 5 mmol L(-1). PMID:23082313

  10. Effect of Electrode Dimensionality and Morphology on the Performance of Cu2Sb Thin Film Electrodes for Li-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Trahey, Lynn; Kung, Harold H; Thackeray, Michael; Vaughey, John T.

    2011-08-09

    Although graphitic carbons have been commercially used in lithium-ion batteries for many years, their low crystallographic density limits their use in applications where space is at a premium. Among the alternative anode materials being considered for these applications are Zintl phases and intermetallic insertion anodes. Historically, main-group-metal-based anode materials have had problems with respect to volume expansion experienced on lithiation and its effect on cycle life. In this paper, we report the role of morphology and electrode dimensionality in extending the cycle life of the intermetallic insertion anode Cu₂Sb. We have found that controlling the surface area of the active material and building internal volume into the electrode structure significantly decreases the capacity fade on cycling. The decrease in fade rate may be due to the active material gradient identified within the structure produced by the electrodeposition process. This enhancement in cycling can be attributed to keeping the displaced copper closer to the active particles and to reducing the diffusion distances within the electrode.

  11. 钛酸铋钠钾无铅压电厚膜的制备及表征%Preparation and Characterization of Sodium-potassium Bismuth Titanate Lead Free Piezoelectric Thick Films

    Institute of Scientific and Technical Information of China (English)

    张海波; 姜胜林; 曾亦可; 张洋洋

    2009-01-01

    (Na0.82K0.18)0.5Bi0.5TiO3 lead free piezoelectric ceramic powders were prepared by using solid phase synthesis, The organic vehicles consisted 5% ethyl cellulose as binder, 2% 2-(2-n-Butoxyethoxy)ethyl as dispersing agent, 1% dibutyl phthalate as a plasticizer, and 92% α-terpineol as solvent (α-terpineol). The screen printing pastes were produced by mixing the ceramicpowders and the organic vehicles together with the mas ratio of 3:1.The BNKT thick films were screen printed with a 320 mesh screen mask on Pt electroded 96% alumina substrates, after leveling, dring, presintering, pressing and sintering the The resulting 40 μm thick films have average grain size of 1.1 μm, maximum relative permittivity of 782, dielectric loss of 3.6% (at 10 kHz), remnant polarization of 24.8 μC/cm2, coercive field of 71.6 kV/cm, and longitudinal piezoelectric coefficient d33 of 79 pC/N.%采用传统固相法制备(Na0.82K0.18)0.5Bi0.5TiO3无铅压电陶瓷粉体,将质量分数5%的乙基纤维素溶入到质量分数为92%的松油醇中配制粘合剂溶液,加入质量分数2%的二乙二醇丁醚醋酸酯作分散剂,质量分数1%的邻苯二甲酸二丁酯作增塑剂,将陶瓷粉体与粘合剂溶液按3:1的质量比混合碾磨,用320目筛印刷至带有Pt电极的氧化铝衬底上,经放平、烘烤、预烧、加压及烧结后,制备出厚度约40 μm的BNKT厚膜,平均晶粒尺寸为1.1 μm,介电常数也达到最大为782,损耗最小为3.6%(10 kHz),剩余极化为24.8 μC/cm2矫顽场为71.6 kV/cm,纵向压电系数为79 pC/N.

  12. Influence of Oxygen Concentration on the Performance of Ultra-Thin RF Magnetron Sputter Deposited Indium Tin Oxide Films as a Top Electrode for Photovoltaic Devices

    Directory of Open Access Journals (Sweden)

    Jephias Gwamuri

    2016-01-01

    Full Text Available The opportunity for substantial efficiency enhancements of thin film hydrogenated amorphous silicon (a-Si:H solar photovoltaic (PV cells using plasmonic absorbers requires ultra-thin transparent conducting oxide top electrodes with low resistivity and high transmittances in the visible range of the electromagnetic spectrum. Fabricating ultra-thin indium tin oxide (ITO films (sub-50 nm using conventional methods has presented a number of challenges; however, a novel method involving chemical shaving of thicker (greater than 80 nm RF sputter deposited high-quality ITO films has been demonstrated. This study investigates the effect of oxygen concentration on the etch rates of RF sputter deposited ITO films to provide a detailed understanding of the interaction of all critical experimental parameters to help create even thinner layers to allow for more finely tune plasmonic resonances. ITO films were deposited on silicon substrates with a 98-nm, thermally grown oxide using RF magnetron sputtering with oxygen concentrations of 0, 0.4 and 1.0 sccm and annealed at 300 °C air ambient. Then the films were etched using a combination of water and hydrochloric and nitric acids for 1, 3, 5 and 8 min at room temperature. In-between each etching process cycle, the films were characterized by X-ray diffraction, atomic force microscopy, Raman Spectroscopy, 4-point probe (electrical conductivity, and variable angle spectroscopic ellipsometry. All the films were polycrystalline in nature and highly oriented along the (222 reflection. Ultra-thin ITO films with record low resistivity values (as low as 5.83 × 10−4 Ω·cm were obtained and high optical transparency is exhibited in the 300–1000 nm wavelength region for all the ITO films. The etch rate, preferred crystal lattice growth plane, d-spacing and lattice distortion were also observed to be highly dependent on the nature of growth environment for RF sputter deposited ITO films. The structural, electrical

  13. Electrocatalytic Oxidation and Ion Chromatography Detection of S2O32-, SO32-, I- and SCN- at Glassy Carbon Electrode with Functionalized Multi-Wall Carbon Nanotubes Film

    Institute of Scientific and Technical Information of China (English)

    XU Ji-ming; WANG Yan-ping; XIAN Yue-zhong; JIN Li-tong

    2004-01-01

    In this research, a glassy carbon electrode modified with the functionalized multi-wall carbon nanotubes (MWNT-COOHs) film was used as an amperometric sensor for the determination of S2O32-, SO23-, I- and SCN-. The electrochemical behavior of those oxidizable inorganic anions at this modified electrode was studied by means of cyclic voltammetry(CV). The experimental results indicate that the modified electrode exhibits a high electrocatalytic activity towards the oxidation of those anions with a relatively high sensitivity, a good stability and a long-life. Separated by ion chromatography(IC) with 1.25 mmol/L H2SO4 as an eluent,those oxidizable anions can be determined by the MWNT-COOHs modified electrode successfully. Under the optimal chromatographic conditions, the detection limits are 1.5 × 10-7 mol/L for S2O23-, 2. 5 × 10-7 mol/L for SO32-, 1.2 × 10-7 mol/L for I- and 2. 0 × 10-7 mol/L for SCN-, respectively. The method was applied successfully to the determination of those anions in environmental water.

  14. Self-assembled Thiolated Calix[n]arene (n=4, 6, 8) Films on Gold Electrodes and Application for Electrochemical Determination Dopamine

    International Nuclear Information System (INIS)

    Highlights: • TCnA/GE was prepared by using a simple self-assembled strategy. • Multilayer self-assembled films of TCnA molecules were fabricated on GE. • TCnA/GE exhibited high supramolecular recognition and enrichment capability. • TC8A/GE showed excellent electrochemical performance for DA. - Abstract: In this study, gold electrodes (GE) modified with three kinds of thiolated calix[4,6,8]arenes (TCnA: TC4A, TC6A, TC8A) were successfully prepared using a simple self-assembly strategy. Three self-assembled films were characterized by cyclic voltammetry measurement, electrochemical impedance spectroscopy, static contact angle measurement and atomic force microscopy. The results confirmed that TCnA molecules effectively absorbed onto the surface of gold electrodes to fabricate the multilayer self-assembled films. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurement showed that the TCnA/GE exhibited high supramolecular recognition and enrichment capability and consequently displayed good electrochemical response toward dopamine (DA). Especially, TC8A/GE exhibited an excellent electrochemical performance for DA with high current densities of 1.5 mA mmol−1 L cm−2, broad linear range (1 × 10−6 to 1 × 10−3 mol L−1) and low detection limit (5 × 10−7 mol L−1). The mechanism of supramolecular recognition and enrichment capability of TCnA/GE was discussed

  15. Control of oxygen octahedral rotation in BiFeO3 films using modulation of SrRuO3 bottom electrode layer

    Science.gov (United States)

    Lee, Sungsu; Jo, Ji Young

    2015-03-01

    Oxygen octahedral rotation of multiferroic BiFeO3 (BFO) has attracted great attention due to changes of electrical and magnetic properties. Coupling of octahedral rotation in BFO-bottom electrode layer interface remains unexplored. Recently, there have been reported the control of octahedral rotation in SrRuO3 (SRO) film on SrTiO3 (001) substrate by coherently controlling the oxygen pressure during growth and interfacial coupling. Here we demonstrate that the octahedral rotation of BFO film is changed using tetragonal a0a0c- tilted-SRO bottom electrodes. In this work, BFO/SRO heterostructure is fabricated to SrTiO3 (001) single crystal substrates by pulsed laser deposition at different oxygen partial pressures. The rotation pattern of FeO6 and the structural symmetry are identified from half-integer reflections using high-resolution X-ray diffraction. The effects depending on octahedral tilting of BFO films on the magnetic and ferroelectric properties will be presented.

  16. CaCu3Ti4O12 thin films on conductive oxide electrode: A comparative study between chemical and physical vapor deposition routes

    International Nuclear Information System (INIS)

    Highlights: ► Dielectrics growth and characterization is one of the most hot topics of materials science and microelectronics. ► CaCu3Ti4O12 perovskite, recently, demonstrated to possess peculiar dielectric properties (Science, 2001, 293, 673–676). ► To date no deep discussion on the growth processes, properties and perspective of CCTO thin films has been proposed. ► Our paper is an effective example of interdisciplinarity, since the comparison between PLD and MOCVD has been addressed. ► Great attention has been paid to CaCu3Ti4O12 film/substrate interfaces since dielectric properties are strongly affected. - Abstract: Metal Organic Chemical Vapor Deposition (MOCVD) and Pulsed Laser Deposition (PLD) techniques have been used for the growth of CaCu3Ti4O12 (CCTO) thin films on La0.9Sr1.1NiO4/LaAlO3 (LSNO/LAO) stack. (1 0 0) oriented CCTO films have been formed through both deposition routes and film complete structural and morphological characterizations have been carried out using several techniques (X-ray diffraction, scanning electron microscopy, energy-filtered transmission electron microscopy). The comparative study demonstrated some differences at the CCTO/LSNO interfaces depending on the adopted deposition technique. Chemical/structural modification of the LSNO electrode probably occurred as a function of the different oxygen partial pressure used in the PLD and MOCVD processes.

  17. Photoelectrolytic hydrogen production using Bi{sub 2}MNbO{sub 7} (M = Al, Ga) semiconductor film electrodes prepared by dip-coating

    Energy Technology Data Exchange (ETDEWEB)

    Rosas-Barrera, K.L. [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara, Km. 2 via El Refugio, C.P. 681011, Piedecusta, Santander (Colombia); Pedraza-Avella, J.A. [Centro de Investigaciones en Catalisis - CICAT, Universidad Industrial de Santander - UIS, Sede Guatiguara, Km. 2 via El Refugio, C.P. 681011, Piedecuesta, Santander (Colombia); Ballen-Gaitan, B.P.; Cortes-Pena, J.; Pedraza-Rosas, J.E. [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara, Km. 2 via El Refugio, C.P. 681011, Piedecusta (Santander) (Colombia); Laverde-Catano, D.A., E-mail: dlaverde@uis.edu.co [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara, Km. 2 via El Refugio, C.P. 681011, Piedecusta, Santander (Colombia)

    2011-10-25

    The performance of Bi{sub 2}MNbO{sub 7} (M = Al, Ga) films on AISI/SAE 304 stainless steel was evaluated in the photoelectrochemical hydrogen production as a function of the annealing temperature of the films (400, 500 and 600 deg. C) and the composition of the electrolyte solution (containing KOH, KCN and KCl). The films were prepared by sol-gel dip-coating on AISI/SAE 304 stainless steel followed by a thermal annealing. The photoelectrochemical evaluation (UV-Vis, 2.5 V) was carried out in a conventional two-compartment electrochemical cell by using the prepared films as photoanode and a silver plate as cathode. During the process, circulating current was recorded and hydrogen production and cyanide degradation were measured. In both cases, it was found that the higher activity was obtained with the films annealed at 500 deg. C and using an electrolyte solution 0.3 M of KOH and 120 ppm of CN{sup -}. Further works on the subject should involve a cathode evaluation to avoid the electrode polarization in presence of KCl and an experimental design to optimize the evaluated variables.

  18. Studies on distribution of element contents in transient layer at interface between boron-doped diamond film electrode and tantalum substrate

    International Nuclear Information System (INIS)

    The boron-doped diamond film (BDD) grown on tantalum (Ta) substrate as an electrode (BDD/Ta) was prepared by hot filament chemical vapor deposition method. The experimental results demonstrated that our BDD/Ta had high current efficiency, strong ability to degrade wastewater, good corrosion stability and long lifetime. These excellent characteristics of BDD/Ta have been explained in terms of Rutherford backscattering (RBS) experiments. RBS investigation revealed that the continuous transient layer at the interface between boron-doped diamond film and Ta-substrate was formed and the microstructure of the continuous transient layer given by the continuous distribution of all element contents at the interface was obtained. The thicknesses of boron-doped diamond film and the continuous transient layer were about equal to 8000 x 1015 atoms/cm2 and 5800 x 1015 atoms/cm2, respectively. The formation of the continuous transient layer at the interface can eliminate the mismatch of thermal expansion coefficients (TEC) at the interface and only lead to the slow change of TEC because of the continuous distribution of element contents of the film and substrate in the transient layer at the interface. Thus, there is no residual stress to concentrate on the interface and the stress-corrosion delamination of the film disappears. Therefore, the corrosion stability and lifetime of BDD/Ta increase and last well, that have been verified by X-ray diffraction (XRD) experiments.

  19. Studies on distribution of element contents in transient layer at interface between boron-doped diamond film electrode and tantalum substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liang Jiachang, E-mail: jcliang@cauc.edu.cn [College of Science, Civil Aviation University of China, Jin Bei highway No.2898, Southern campus of Civil Aviation, Tianjin 300300 (China); Gao Chengyao [Chinese People' s Armed Police Forces Academy, Langfang, Hebei 065000 (China); Zhang Liping [College of Science, Civil Aviation University of China, Jin Bei highway No.2898, Southern campus of Civil Aviation, Tianjin 300300 (China); Jiang Lihui [Tianjin Key Laboratory for Advanced Signal Processing, Civil Aviation University of China, Tianjin 300300 (China); Yang Zhengquan; Wang Zhiping; Ji Chaohui [College of Science, Civil Aviation University of China, Jin Bei highway No.2898, Southern campus of Civil Aviation, Tianjin 300300 (China); Le Xiaoyun; Rong Cuihua [School of Physics and Nuclear Energy Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Zhang Jian [Hainan Airlines Group, Hainan 570206 (China)

    2011-05-01

    The boron-doped diamond film (BDD) grown on tantalum (Ta) substrate as an electrode (BDD/Ta) was prepared by hot filament chemical vapor deposition method. The experimental results demonstrated that our BDD/Ta had high current efficiency, strong ability to degrade wastewater, good corrosion stability and long lifetime. These excellent characteristics of BDD/Ta have been explained in terms of Rutherford backscattering (RBS) experiments. RBS investigation revealed that the continuous transient layer at the interface between boron-doped diamond film and Ta-substrate was formed and the microstructure of the continuous transient layer given by the continuous distribution of all element contents at the interface was obtained. The thicknesses of boron-doped diamond film and the continuous transient layer were about equal to 8000 x 10{sup 15} atoms/cm{sup 2} and 5800 x 10{sup 15} atoms/cm{sup 2}, respectively. The formation of the continuous transient layer at the interface can eliminate the mismatch of thermal expansion coefficients (TEC) at the interface and only lead to the slow change of TEC because of the continuous distribution of element contents of the film and substrate in the transient layer at the interface. Thus, there is no residual stress to concentrate on the interface and the stress-corrosion delamination of the film disappears. Therefore, the corrosion stability and lifetime of BDD/Ta increase and last well, that have been verified by X-ray diffraction (XRD) experiments.

  20. Oxidation-Resistant of Cr/Cu/Al/Cr Thin Film Electrodes%Cr/Cu/Al/Cr薄膜电极的防氧化性能

    Institute of Scientific and Technical Information of China (English)

    翁卫祥; 于光龙; 贾贞; 李昱; 郭太良

    2011-01-01

    Novel Cr/Cu/Al/Cr thin film electrodes were prepared by DC magnetron sputtering and wet etching technology, in which Al thin film was used as the protective layer for Cu layer.The change of the crystal structure, surface morphology and electric resistivity of the thin films and electrodes before and after heat treatment were studied.The Al layer played a key role as an oxygen diffusion barrier layer, for its protection, the Cr/Cu/Al/Cr thin film still had good thermal stability when the heat treatment was below 600 ℃.Meanwhile, the oxidation diffusion from the lateral edge of the electrodes as the temperature increased caused the decrease of the conduction of the electrodes.The electric resistivity was increasing obviously after 500 ℃ heat treatment, and the oxidation region was expanded from the edge to the surface of the electrode.Nonetheless, the thin film electrode fulfilled the requirements of field emission device for its stable resistance when post annealing temperature was 430 ℃, which was 7.2× 10-8 Ω · m.Based on the new electrode, the FED device was fabricated for verifying its oxidation resistance.%采用Al作为Cu导电层的主要防氧化保护层,在普通浮法玻璃上利用磁控溅射和湿法刻蚀技术制备Cr/Cu/Al/Cr复合薄膜及其电极,研究不同的热处理温度对复合薄膜及其电极的结构、表面形貌和导电性能的影响.由于有Al层作为保护层,在热处理过程中,Al先与穿过Cr保护层的氧进行反应,从而可以更有效地保护Cu膜层在较高的温度下不被氧化,所制备的薄膜在经过600℃的热处理之后仍然具有较好的导电性能.而对于Cr/Cu/Al/Cr电极,侧面裸露的金属层在热处理过程中的氧化是其导电性能逐渐下降的主要原因,退火温度超过500℃之后,电极侧面裸露部分的氧化范围不断往电极的中间扩散,导致了薄膜电极导电性能显著恶化.虽然如此,Cr/Cu/Al/Cr薄膜电极在430℃附近仍然具有较好