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

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...... 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...

Carbon film electrodes for super capacitor applications

Science.gov (United States)

Tan, Ming X.

1999-01-01

A microporous carbon film for use as electrodes in energy strorage devices is disclosed, which is made by the process comprising the steps of: (1) heating a polymer film material consisting essentially of a copolymer of polyvinylidene chloride and polyvinyl chloride in an inert atmosphere to form a carbon film; and (2) activating said carbon film to form said microporous carbon film having a density between about 0.7 g/cm.sup.2 and 1 g/cm.sup.2 and a gravimetric capacitance of about between 120 F/g and 315 F/g.

Room-Temperature Multiferroics and Thermal Conductivity of 0.85BiFe1-2xTixMgxO3-0.15CaTiO3 Epitaxial Thin Films (x = 0.1 and 0.2).

Science.gov (United States)

Zhang, Ji; Sun, Wei; Zhao, Jiangtao; Sun, Lei; Li, Lei; Yan, Xue-Jun; Wang, Ke; Gu, Zheng-Bin; Luo, Zhen-Lin; Chen, Yanbin; Yuan, Guo-Liang; Lu, Ming-Hui; Zhang, Shan-Tao

2017-08-02

Thin films of 0.85BiFe 1-2x Ti x Mg x O 3 -0.15CaTiO 3 (x = 0.1 and 0.2, abbreviated to C-1 and C-2, respectively) have been fabricated on (001) SrTiO 3 substrate with and without a conductive La 0.7 Sr 0.3 MnO 3 buffer layer. The X-ray θ-2θ and ϕ scans, atomic force microscopy, and cross-sectional transmission electron microscopy confirm the (001) epitaxial nature of the thin films with very high growth quality. Both the C-1 and C-2 thin films show well-shaped magnetization-magnetic field hysteresis at room temperature, with enhanced switchable magnetization values of 145.3 and 42.5 emu/cm 3 , respectively. The polarization-electric loops and piezoresponse force microscopy measurements confirm the room-temperature ferroelectric nature of both films. However, the C-1 films illustrate a relatively weak ferroelectric behavior and the poled states are easy to relax, whereas the C-2 films show a relatively better ferroelectric behavior with stable poled states. More interestingly, the room-temperature thermal conductivity of C-1 and C-2 films are measured to be 1.10 and 0.77 W/(m·K), respectively. These self-consistent multiferroic properties and thermal conductivities are discussed by considering the composition-dependent content and migration of Fe-induced electrons and/or charged point defects. This study not only provides multifunctional materials with excellent room-temperature magnetic, ferroelectric, and thermal conductivity properties but may also stimulate further work to develop BiFeO 3 -based materials with unusual multifunctional properties.

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

KAUST Repository

Catrysse, Peter B.; Fan, Shanhui

2010-01-01

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

Rough Electrode Creates Excess Capacitance in Thin-Film Capacitors.

Science.gov (United States)

Torabi, Solmaz; Cherry, Megan; Duijnstee, Elisabeth A; Le Corre, Vincent M; Qiu, Li; Hummelen, Jan C; Palasantzas, George; Koster, L Jan Anton

2017-08-16

The parallel-plate capacitor equation is widely used in contemporary material research for nanoscale applications and nanoelectronics. To apply this equation, flat and smooth electrodes are assumed for a capacitor. This essential assumption is often violated for thin-film capacitors because the formation of nanoscale roughness at the electrode interface is very probable for thin films grown via common deposition methods. In this work, we experimentally and theoretically show that the electrical capacitance of thin-film capacitors with realistic interface roughness is significantly larger than the value predicted by the parallel-plate capacitor equation. The degree of the deviation depends on the strength of the roughness, which is described by three roughness parameters for a self-affine fractal surface. By applying an extended parallel-plate capacitor equation that includes the roughness parameters of the electrode, we are able to calculate the excess capacitance of the electrode with weak roughness. Moreover, we introduce the roughness parameter limits for which the simple parallel-plate capacitor equation is sufficiently accurate for capacitors with one rough electrode. Our results imply that the interface roughness beyond the proposed limits cannot be dismissed unless the independence of the capacitance from the interface roughness is experimentally demonstrated. The practical protocols suggested in our work for the reliable use of the parallel-plate capacitor equation can be applied as general guidelines in various fields of interest.

Performance of a polymer electrolyte membrane fuel cell with thin film catalyst electrodes

Energy Technology Data Exchange (ETDEWEB)

Chun, Young Gab; Kim, Chang Soo; Peck, Dong Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of)

1998-03-15

In order to develop a kW-class polymer electrolyte membrane fuel cell (PEMFC), several electrodes have been fabricated by different catalyst layer preparation procedures and evaluated based on the cell performance. Conventional carbon paper and carbon cloth electrodes were fabricated using a ptfe-bonded Pt/C electrol catalyst by coating and rolling methods. Thin-film catalyst/ionomer composite layers were also formed on the membrane by direct coating and transfer printing techniques. The performance evaluation with catalyst layer preparation methods was carried out using a large or small electrode single cell. Conventional and thin film membrane and electrode assemblies (MEAs) with small electrode area showed a performance of 350 and 650 mA/cm{sup 2} at 0.6 V, respectively. The performance of direct coated thin film catalyst layer with 300 cm{sup 2} MEAs was higher than those of the conventional and transfer printing technique MEAs. The influence of some characteristic parameters of the thin film electrode on electrochemical performance was examined. Various other aspects of overall operation of PEMFC stacks were also discussed. (orig.)

Ultrahigh PEMFC performance of a thin-film, dual-electrode assembly with tailored electrode morphology.

Science.gov (United States)

Jung, Chi-Young; Kim, Tae-Hyun; Yi, Sung-Chul

2014-02-01

A dual-electrode membrane electrode assembly (MEA) for proton exchange membrane fuel cells with enhanced polarization under zero relative humidity (RH) is fabricated by introducing a phase-separated morphology in an agglomerated catalyst layer of Pt/C (platinum on carbon black) and Nafion. In the catalyst layer, a sufficient level of phase separation is achieved by dispersing the Pt catalyst and the Nafion dispersion in a mixed-solvent system (propane-1,2,3-triol/1-methyl-2-pyrrolidinone).The high polymer chain mobility results in improved water uptake and regular pore-size distribution with small pore diameters. The electrochemical performance of the dual-film electrode assembly with different levels of phase separation is compared to conventional electrode assemblies. As a result, good performance at 0 % RH is obtained because self-humidification is dramatically improved by attaching this dense and phase-separated catalytic overlayer onto the conventional catalyst layer. A MEA prepared using the thin-film, dual-layered electrode exhibits 39-fold increased RH stability and 28-fold improved start-up recovery time during the on-off operation relative to the conventional device. We demonstrate the successful operation of the dual-layered electrode comprised of discriminatively phase-separated agglomerates with an ultrahigh zero RH fuel-cell performance reaching over 95 % performance of a fully humidified MEA. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characteristics of sputtered Al-doped ZnO films for transparent electrodes of organic thin-film transistor

International Nuclear Information System (INIS)

Park, Yong Seob; Kim, Han-Ki

2011-01-01

Aluminum-doped ZnO (AZO) thin-films were deposited with various RF powers at room temperature by radio frequency (RF) magnetron sputtering method. The electrical properties of the AZO film were improved with the increasing RF power. These results can be explained by the improvement of the crystallinity in the AZO film. We fabricated the organic thin-film transistor (OTFT) of the bottom gate structure using pentacene active and poly-4-vinyl phenol gate dielectric layers on the indium tin oxide gate electrode, and estimated the device properties of the OTFTs including drain current-drain voltage (I D -V D ), drain current-gate voltage (I D -V G ), threshold voltage (V T ), on/off ratio and field effect mobility. The AZO film that grown at 160 W RF power exhibited low resistivity (1.54 x 10 -3 Ω.cm), high crystallinity and uniform surface morphology. The pentacene thin-film transistor using the AZO film that's fabricated at 160 W RF power exhibited good device performance such as the mobility of 0.94 cm 2 /V s and the on/off ratio of ∼ 10 5 . Consequently, the performance of the OTFT such as larger field-effect carrier mobility was determined the conductivity of the AZO source/drain (S/D) electrode. AZO films prepared at room temperature by the sputtering method are suitable for the S/D electrodes in the OTFTs.

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

International Nuclear Information System (INIS)

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. (cross-disciplinary physics and related areas of science and technology)

Film stresses and electrode buckling in organic solar cells

KAUST Repository

Brand, Vitali; Levi, Kemal; McGehee, Michae D.; Dauskardt, Reinhold H.

2012-01-01

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

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)

Optimized electrode coverage of membrane actuators based on epitaxial PZT thin films

International Nuclear Information System (INIS)

Nguyen, M D; Dekkers, M; Blank, D H A; Rijnders, G; Nazeer, H

2013-01-01

This research presents an optimization of piezoelectric membrane actuators by maximizing the actuator displacement. Membrane actuators based on epitaxial Pb(Zr,Ti)O 3 thin films grown on all-oxide electrodes and buffer layers using silicon technology were fabricated. Electrode coverage was found to be an important factor in the actuation displacement of the piezoelectric membranes. The optimum electrode coverage for maximum displacement was theoretically determined to be 39%, which is in good agreement with the experimental results. Dependences of membrane displacement and optimum electrode coverage on membrane diameter and PZT-film/Si-device-layer thickness ratio have also been investigated. (paper)

Amperometric Noise at Thin Film Band Electrodes

DEFF Research Database (Denmark)

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

2012-01-01

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...

Voltammetric and impedance behaviours of surface-treated nano-crystalline diamond film electrodes

International Nuclear Information System (INIS)

Liu, F. B.; Jing, B.; Cui, Y.; Di, J. J.; Qu, M.

2015-01-01

The electrochemical performances of hydrogen- and oxygen-terminated nano-crystalline diamond film electrodes were investigated by cyclic voltammetry and AC impedance spectroscopy. In addition, the surface morphologies, phase structures, and chemical states of the two diamond films were analysed by scanning probe microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results indicated that the potential window is narrower for the hydrogen-terminated nano-crystalline diamond film than for the oxygen-terminated one. The diamond film resistance and capacitance of oxygen-terminated diamond film are much larger than those of the hydrogen-terminated diamond film, and the polarization resistances and double-layer capacitance corresponding to oxygen-terminated diamond film are both one order of magnitude larger than those corresponding to the hydrogen-terminated diamond film. The electrochemical behaviours of the two diamond film electrodes are discussed

Facile green synthesis of silver nanodendrite/cellulose acetate thin film electrodes for flexible supercapacitors.

Science.gov (United States)

Devarayan, Kesavan; Park, Jiyoung; Kim, Hak-Yong; Kim, Byoung-Suhk

2017-05-01

In this study, we present a highly efficient and economical solution called as 'in situ hydrogenation' for preparation of highly conductive thin film electrode based on silver nanodendrites. The silver nanodendrite (AgND)/cellulose acetate (CA) thin film electrodes exhibited sheet resistance ranging from 0.32ohm/sq to 122.1ohm/sq which could be controlled by changing the concentration of both silver and polymer. In addition, these electrodes exhibited outstanding toughness during the bending test. Further, these thin film electrodes have great potential for scale-up with an average weight of 3mg/cm 2 and can be also combined with active nanomaterials such as multiwalled carbon nanotubes (MWCNTs) to fabricate AgND/CA/MWCNTs thin film for high-performance flexible supercapacitor electrode. The AgND/CA/MWCNTs electrodes exhibited a maximum specific capacitance of 237F/g at a current density of 0.3A/g. After 1000 cycles, the AgND/MWCNT/CA exhibited a decrease of 16.0% of specific capacitance. Copyright © 2017 Elsevier Ltd. All rights reserved.

In and Ga Codoped ZnO Film as a Front Electrode for Thin Film Silicon Solar Cells

Directory of Open Access Journals (Sweden)

Duy Phong Pham

2014-01-01

Full Text Available Doped ZnO thin films have attracted much attention in the research community as front-contact transparent conducting electrodes in thin film silicon solar cells. The prerequisite in both low resistivity and high transmittance in visible and near-infrared region for hydrogenated microcrystalline or amorphous/microcrystalline tandem thin film silicon solar cells has promoted further improvements of this material. In this work, we propose the combination of major Ga and minor In impurities codoped in ZnO film (IGZO to improve the film optoelectronic properties. A wide range of Ga and In contents in sputtering targets was explored to find optimum optical and electrical properties of deposited films. The results show that an appropriate combination of In and Ga atoms in ZnO material, followed by in-air thermal annealing process, can enhance the crystallization, conductivity, and transmittance of IGZO thin films, which can be well used as front-contact electrodes in thin film silicon solar cells.

Investigation of interaction between silver oxide electrode and separator hydrated cellulose film in silver-cadmium accumulators

International Nuclear Information System (INIS)

Molotkova, E.N.; Yarochkina, E.N.

1975-01-01

Oxidation-reduction interaction of the oxysilver electrode with hydrocellulose film during storing charged silver-cadmium accumulators. It was demonstrated that accumulator electric characteristics durinq storing are linearly depending on the capacity of this hydrocellulose film to interact with silver oxide: the more silver is absorbed by film the quicker is the decreasing of the electromotive force and capacity of the accumulators. Preservation of the silver electrode capacity in the silver-cadmium accumulators is determined first of all by hydrocellulose separation film properties and especially by film layer adjacent to positive electrode. The more inert film layer is, regarding to silver oxide in the electrolite, the slower is dissolution of the electrode and also decompousing speed of AgO, the longer is the accumulator preservation time

Electrocatalytic behaviour of hybrid cobalt–manganese hexacyanoferrate film on glassy carbon electrode

International Nuclear Information System (INIS)

Vinu Mohan, A.M.; Rambabu, Gutru; Aswini, K.K.; Biju, V.M.

2014-01-01

A thin film of hybrid cobalt–manganese hexacyanoferrate (CoMnHCF), a redox mediator was electrodeposited on a glassy carbon (GC) electrode and was employed as an amperometric sensor towards L-Tryptophan (L-Trp). The hybrid film was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction technique (XRD), scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDAX), and electrochemical techniques. The atomic absorption spectroscopic analysis provided the stoichiometry of the hybrid film to be K 1.74-y Co y Mn 0.78 [Fe(CN) 6 ], y ≤ 0.68. The electrochemical impedance study revealed the excellent charge transfer properties of GC/CoMnHCF electrode. The voltammetric investigations demonstrated exceptional electrocatalytic properties of the hybrid film modified electrode when compared to that of bare GC, GC/CoHCF and GC/MnHCF electrodes, towards the L-Trp oxidation. The kinetic parameters such as electron transfer coefficient, the electron transfer rate constant, the diffusion coefficient and the catalytic rate constant for the electrooxidation process of L-Trp were investigated. The amperometric detection of L-Trp employing GC/CoMnHCF electrode possessed a good sensitivity of 10 × 10 −2 A M −1 cm −2 in a wide range of detection (2–200 μM) at a reduced overpotential of 680 mV. In addition, the proposed amperometric method was applied to the detection of L-Trp in commercial milk samples with reproducible results. - Highlights: • A hybrid cobalt–manganese hexacyanoferrate film was prepared. • The hybrid film possesses excellent charge transfer properties. • The hybrid film exhibits excellent electrocatalytic properties towards Tryptophan. • Tryptophan detection is possible from commercial milk samples

Cost-effective disposable thiourea film modified copper electrode for capacitive immunosensor

International Nuclear Information System (INIS)

Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Wongkittisuksa, Booncharoen; Asawatreratanakul, Punnee; Limsakul, Chusak

2010-01-01

Cost-effective disposable electrodes were fabricated from copper clad laminate, usually used for printed circuit board (PCB) in electronic industries, by using dry film photoresist. Electro-oxidation (anodisation) was employed to obtain a good formation of thiourea film on the electrode surface. The affinity binding pair of carcinoembryonic antigen (CEA) and anti-carcinoembryonic antigen (anti-CEA) was used as a model system. Anti-CEA was immobilized on thiourea film via covalent coupling. This modified electrode was incorporated with a capacitive system for CEA analysis. This capacitive immunosensor provided a linear range between 0.01 and 10 ng ml -1 with a detection limit of 10 pg ml -1 . When applied to analyze CEA in serum samples, the results agreed well with the enzyme linked fluorescent assay (ELFA) technique (P > 0.05). The proposed strategy for the preparation of disposable modified copper electrode is very cost effective and simple. Moreover, it provides good reproducibility. This technique can easily be applied to immobilize other biological sensing elements for biosensors development.

Flexible probe for measuring local conductivity variations in Li-ion electrode films

Science.gov (United States)

Hardy, Emilee; Clement, Derek; Vogel, John; Wheeler, Dean; Mazzeo, Brian

2018-04-01

Li-ion battery performance is governed by electronic and ionic properties of the battery. A key metric that characterizes Li-ion battery cell performance is the electronic conductivity of the electrodes, which are metal foils with thin coatings of electrochemically active materials. To accurately measure the spatial variation of electronic conductivity of these electrodes, a micro-four-line probe (μ4LP) was designed and used to non-destructively measure the properties of commercial-quality Li-ion battery films. This previous research established that the electronic conductivity of film electrodes is not homogeneous throughout the entirety of the deposited film area. In this work, a micro-N-line probe (μNLP) and a flexible micro-flex-line probe (μFLP) were developed to improve the non-destructive micro-scale conductivity measurements that we can take. These devices were validated by comparing test results to that of the predecessor, the micro-four-line probe (μ4LP), on various commercial-quality Li-ion battery electrodes. Results show that there is significant variation in conductivity on a millimeter and even micrometer length scale through the electrode film. Compared to the μ4LP, the μNLP and μFLP also introduce additional measurement configuration possibilities, while providing a more robust design. Researchers and manufacturers can use these probes to identify heterogeneity in their electrodes during the fabrication process, which will lead to the development of better batteries.

Portable cholesterol detection with polyaniline-carbon nanotube film based interdigitated electrodes

International Nuclear Information System (INIS)

Nguyen, Le Huy; Nguyen, Ngoc Thinh; Nguyen, Hai Binh; Tran, Dai Lam; Nguyen, Tuan Dung

2012-01-01

Polyaniline-carboxylic multiwalled carbon nanotubes composite film (PANi-MWCNT) has been polymerized on the surface of interdigitated platinum electrode (fabricated by MEMS technology) which was compatibly connected to Autolab interface via universal serial bus (USB). An amperometric biosensor based on covalent immobilization of cholesterol oxidase (ChOx) on PANi–MWCNT film with potassium ferricyanide (FeCN) as the redox mediator was developed. The mediator helps to shuttle the electrons between the immobilized ChOx and the PANi-MWCNT electrode, therefore operating at a low potential of −0.3 V compared to the saturated calomel electrode (SCE). This potential precludes the interfering compounds from oxidization. The bio-electrode exhibits good linearity from 0.02 to 1.2 mM cholesterol concentration with a correlation coefficient of 0.9985

High power density supercapacitor electrodes of carbon nanotube films by electrophoretic deposition

International Nuclear Information System (INIS)

Du Chunsheng; Pan Ning

2006-01-01

Carbon nanotube thin films have been successfully fabricated by the electrophoretic deposition technique. The supercapacitors built from such thin film electrodes have a very small equivalent series resistance, and a high specific power density over 20 kW kg -1 was thus obtained. More importantly, the supercapacitors showed superior frequency response. Our study also demonstrated that these carbon nanotube thin films can serve as coating layers over ordinary current collectors to drastically enhance the electrode performance, indicating a huge potential in supercapacitor and battery manufacturing

Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors

International Nuclear Information System (INIS)

Gouveia-Caridade, Carla; Soares, David M.; Liess, Hans-Dieter; Brett, Christopher M.A.

2008-01-01

The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 Ω and 2.0 kΩ nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investigated 2 Ω carbon film resistors. Cyclic voltammetry was performed in acetate buffer and phosphate buffer saline electrolytes and the kinetic parameters of the model redox system Fe(CN) 6 3-/4- obtained. The 1.5 Ω resistor electrodes show the best properties for sensor development with wide potential windows, similar electrochemical behaviour to those of 2 Ω and close-to-reversible kinetic parameters after electrochemical pre-treatment. The 15 and 140 Ω resistor electrodes show wide potential windows although with slower kinetics, whereas the 2.0 kΩ resistor electrodes show poor cyclic voltammetric profiles even after pre-treatment. Electrochemical impedance spectroscopy related these findings to the interfacial properties of the electrodes. Microstructural and morphological studies were carried out using contact mode Atomic Force Microscopy (AFM), Confocal Raman spectroscopy and X-ray diffraction. AFM showed more homogeneity of the films with lower nominal resistances, related to better electrochemical characteristics. X-ray diffraction and Confocal Raman spectroscopy indicate the existence of a graphitic structure in the carbon films

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.

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.

High PEC conversion efficiencies from CuSe film electrodes modified with metalloporphyrin/polyethylene matrices

International Nuclear Information System (INIS)

Zyoud, Ahed; Al-Kerm, Rola S.; Al-Kerm, Rana S.; Waseem, Mansur; Mohammed, H.S. Helal; Park, DaeHoon; Campet, Guy; Sabli, Nordin; Hilal, Hikmat S.

2015-01-01

Enhancement of hole-transfer across CuSe electrode/liquid junction can be facilitated by coating with metalloporphyrin complexes embedded inside polyethylene matrices. - Highlights: • CuSe films were electrochemically deposited onto FTO/Glass • Annealing CuSe film electrodes enhanced PEC characteristics • PEC characteristics were further enhanced by metalloporphyrin/polyethylene matrices, yielding ∼15% efficiency • Matrix behavior as charge transfer mediator enhanced electrode conversion efficiency and stability - Abstract: Electrodeposited CuSe film electrodes have been prepared onto FTO/glass by a facile method based on earlier methods described for other systems. The films were characterized, modified by annealing and further characterized. The films were then modified by coating with tetra(-4-pyridyl) pophyrinato-manganese (MnTPyP) complexes embedded inside commercial polyethylene (PE) matrices. The effects of modifications on different film properties, such as X-ray diffraction (XRD) patterns, surface morphology, photoluminescence (PL) spectra and electronic absorption spectra were investigated. Compared with other thin film electrode systems, very high photoelectrochemical (PEC) conversion efficiency values have been observed here. Pre-annealing the CuSe films at 150°C for 2 h, followed by attaching the MnTPyP/PE matrices remarkably enhanced their PEC characteristics. The conversion efficiency was significantly enhanced, from less than 1.0% to more than 15%. Fill factor (FF) was also enhanced from ∼30% to ∼80%. Values of open-circuit potential (V OC ) and short-circuit current (J SC ) were significantly enhanced. While annealing affects uniformity, particle inter-connection and surface texture of the CuSe films, the MnTPyP complex species behaves as an additional charge-transfer mediator across the film/electrolyte junction. Optimization of PEC characteristics, using different deposition times, different annealing temperatures, different

Influence of thin film thickness of working electrodes on photovoltaic characteristics of dye-sensitized solar cells

Directory of Open Access Journals (Sweden)

Lai Yeong-Lin

2017-01-01

Full Text Available This paper presents the study of the influence of thin film thickness of working electrodes on the photovoltaic characteristics of dye-sensitized solar cells. Titanium dioxide (TiO2 thin films, with the thickness from 7.67 to 24.3 μm, were used to fabricate the working electrodes of dye-sensitized solar cells (DSSCs. A TiO2 film was coated on a fluorine-doped tin oxide (FTO conductive glass substrate and then sintered in a high-temperature furnace. On the other hand, platinum (Pt solution was coated onto an FTO substrate for the fabrication of the counter electrode of a DSSC. The working electrode immersed in a dye, the counter electrode, and the electrolyte were assembled to complete a sandwich-structure DSSC. The material analysis of the TiO2 films of DSSCs was carried out by scanning electron microscopy (SEM and ultraviolet-visible (UV-Vis spectroscopy, while the photovoltaic characteristics of DSSCs were measured by an AM-1.5 sunlight simulator. The light transmittance characteristics of the TiO2 working electrode depend on the TiO2 film thickness. The thin film thickness of the working electrode also affects the light absorption of a dye and results in the photovoltaic characteristics of the DSSC, including open-circuited voltage (VOC, short-circuited current density (JSC, fill factor, and photovoltaic conversion efficiency.

Determination of zinc and cadmium with characterized Electrodes of carbon and polyurethane modified by a bismuth film

Directory of Open Access Journals (Sweden)

Jossy Karla Brasil Bernardelli

2011-09-01

Full Text Available This study aims to use electrodes modified with bismuth films for the determination of zinc and cadmium. The film was electrodeposited ex situ on a composite carbon electrode with polyurethane and 2% metallic bismuth (2BiE and on a carbon bar electrode (CBE. The electrodes were characterized by scanning electron microscopy and energy dispersive spectroscopy. Through differential pulse anodic stripping voltammetry, the electrodes 2BiE and CBE containing bismuth films showed a limit of detection (LOD of 5.56 × 10-5 and 3.07 × 10-5 g.L-1 for cadmium and 1.24 × 10-4 and 1.53 × 10-4 g.L-1 for zinc, respectively. The presence of a bismuth film increased the sensitivity of both electrodes.

Sulfonated Polyaniline Coated Mercury Film Electrodes for Voltammetric Analysis of Metals in Water

Directory of Open Access Journals (Sweden)

Denise Alves Fungaro

2001-11-01

Full Text Available The electrochemical polymerization of 2-aminobenzenesulfonic acid with and without aniline has been carried by cyclic potencial sweep in sulfuric acid solution at the glassy carbon electrode. The polymer and copolymer formed have been characterized voltammetrically. The sulfonated polyaniline coated mercury thin-film electrodes have been evaluated for use with anodic stripping voltammetry. The electrodes were tested and compared with a conventional thin-film mercury electrode. Calibration plots showed linearity up to 10-7 mol L-1. Detection limits for zinc, lead and cadmium test species are very similar at around 12 nmol L-1. Applications to analysis of waters samples are demonstrated.

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

2015-08-05

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.

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.

Micromachined Dense Palladium Electrodes for Thin-film Solid Acid Fuel Cells

NARCIS (Netherlands)

Unnikrishnan, S.

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

Voltammetric Determination of Guanine on the Electrode Modified by Gold Deposit and Nafion Film

Directory of Open Access Journals (Sweden)

L.G. Shaidarova

2016-09-01

Full Text Available Electrodeposited gold and Nafion-gold composite on the surface of glassy carbon electrodes (GCE have shown electrocatalytic activity during guanine oxidation. In comparison with the unmodified electrode, decreasing of the oxidation potential by 100 mV and increasing of the current of organic compound oxidation have been observed. When the Nafion (NF film is applied to the surface of the glassy carbon electrode with electrodeposited gold, a five-fold increase of guanine oxidation current has been achieved compared to its oxidation on the modified electrode without the NF film. Conditions have been found for electrodeposition of gold on the surface of the glassy carbon electrode, including that one covered with the NF film, as well as for registration of the maximum catalytic current on these electrodes. Linear dependence of the electrocatalytic response of the modified electrode from the guanine concentration has been observed in the range from 5·10–6 to 5·10–3 mol·L–1 (for Au GCE and from 5·10–7 to 5·10–3 mol·L–1 (for NF-Au GCE.

Binder-free manganese oxide/carbon nanomaterials thin film electrode for supercapacitors.

Science.gov (United States)

Wang, Ning; Wu, Chuxin; Li, Jiaxin; Dong, Guofa; Guan, Lunhui

2011-11-01

A ternary thin film electrode was created by coating manganese oxide onto a network composed of single-walled carbon nanotubes and single-walled carbon nanohorns. The electrode exhibited a porous structure, which is a promising architecture for supercapacitors applications. The maximum specific capacitances of 357 F/g for total electrode at 1 A/g were achieved in 0.1 M Na(2)SO(4) aqueous solution.

Nafion/2,2'-bipyridyl-modified bismuth film electrode for anodic stripping voltammetry

International Nuclear Information System (INIS)

Torma, Ferenc; Kadar, Mihaly; Toth, Klara; Tatar, Eniko

2008-01-01

This paper describes the fabrication, characterisation and the application of a Nafion/2,2'-bipyridyl/bismuth composite film-coated glassy carbon electrode (NC(Bpy)BiFE) for the anodic stripping voltammetric determination of trace metal ions (Zn 2+ , Cd 2+ and Pb 2+ ). The NC(Bpy)BiFE electrode is prepared by first applying a 2.5 mm 3 drop of a coating solution containing 0.5 wt% Nafion and 0.1% (w/v) 2,2'-bipyridil (Bpy) onto the surface of a glassy carbon electrode, while the Bi film was plated in situ simultaneously with the target metal ions at -1.4 V. The main advantage of the polymer coated bismuth film electrode is that the sensitivity of the stripping responses is increased considerably due to the incorporation of the neutral chelating agent of 2,2'-bipyridyl (Bpy) in the Nafion film, while the Nafion coating improved the mechanical stability of the bismuth film and its resistance to the interference of surfactants. The key experimental parameters relevant to both the electrode fabrication and the voltammetric measurement were optimized on the basis of the stripping signals. With a 2 min deposition time in the presence of oxygen, linear calibration curves were obtained in a wide concentration range (about 2-0.001 μM) with detection limits of 8.6 nM (0.56 μg dm -3 ) for Zn 2+ , 1.1 nM (0.12 μg dm -3 ) for Cd 2+ and 0.37 nM (0.077 μg dm -3 ) for Pb 2+ . For nine successive preconcentration/determination/electrode renewal experiments the standard deviations were between 3 and 5% at 1.2 μM for zinc and 0.3-0.3 μM concentration level for lead and cadmium, respectively, and the method exhibited excellent selectivity in the presence of the excess of several potential interfering metal ions. The analytical utility of the stripping voltammetric method elaborated was tested in the assay of heavy metals in some real samples and the method was validated by ICP-MS technique

Modified lead titanate thin films for pyroelectric infrared detectors on gold electrodes

Science.gov (United States)

Ahmed, Moinuddin; Butler, Donald P.

2015-07-01

Pyroelectric infrared detectors provide the advantage of both a wide spectral response and dynamic range, which also has enabled systems to be developed with reduced size, weight and power consumption. This paper demonstrates the deposition of lead zirconium titanate (PZT) and lead calcium titanate (PCT) thin films for uncooled pyroelectric detectors with the utilization of gold electrodes. The modified lead titanate thin films were deposited by pulsed laser deposition on gold electrodes. The PZT and PCT thins films deposited and annealed at temperatures of 650 °C and 550 °C respectively demonstrated the best pyroelectric performance in this work. The thin films displayed a pyroelectric effect that increased with temperature. Poling of the thin films was carried out for a fixed time periods and fixed dc bias voltages at elevated temperature in order to increase the pyroelectric coefficient by establishing a spontaneous polarization of the thin films. Poling caused the pyroelectric current to increase one order of magnitude.

Highly conductive and flexible color filter electrode using multilayer film structure

Science.gov (United States)

Han, Jun Hee; Kim, Dong-Young; Kim, Dohong; Choi, Kyung Cheol

2016-07-01

In this paper, a high performance flexible component that serves as a color filter and an electrode simultaneously is suggested. The suggested highly conductive and flexible color filter electrode (CFE) has a multilayer film structure composed of silver (Ag) and tungsten trioxide (WO3). The CFE maintained its color filtering capability even when the films were bent on a polyethylene terephthalate (PET) film. Low sheet resistance of the CFE was obtained using WO3 as a bridge layer that connects two Ag layers electrically. The sheet resistance was less than 2 Ω/sq. and it was negligibly changed after bending the film, confirming the flexibility of the CFE. The CFE can be easily fabricated using a thermal evaporator and is easily patterned by photolithography or a shadow mask. The proposed CFE has enormous potential for applications involving optical devices including large area devices and flexible devices.

Preparation and voltammetric characterization of electrodes coated with Langmuir-Schaefer ultrathin films of Nafion®

Directory of Open Access Journals (Sweden)

Bertoncello Paolo

2003-01-01

Full Text Available Ultrathin films of Nafion® perfluorinated polymer were deposited on indium-tin oxide electrodes (ITO by using Langmuir-Schaefer (LS technique, after optimization of the subphase composition conditions. Morphological characteristics of these coatings were obtained by Atomic Force Microscopy (AFM. Nafion® LS films showed a good uniformity and complete coverage of the electrode surface, however a different organization degree of the polymer layer was evidenced with respect to thin films deposited by spin-coating. ITO electrodes modified with Nafion® LS coatings preconcentrate by ion-exchange electroactive cations, such as Ru[(NH36]3+, dissolved in diluted solutions. The electroactive species is retained by the Nafion® LS coated ITO also after transfer of the modified electrode into pure supporting electrolyte. This allowed the use of the ruthenium complex as voltammetric probe to test diffusion phenomena within the Nafion® LS films. Apparent diffusion coefficients (Dapp of Ru[(NH36]3+ incorporated in Nafion® LS films were obtained by voltammetric measurements. Dapp values decrease slightly by increasing the amount of ruthenium complex incorporated in the ultrathin film. They are significantly lower than values typical for recasted Nafion® films, in agreement with the highly condensed nature of the Nafion® LS fims.

Optically Transparent Thin-Film Electrode Chip for Spectroelectrochemical Sensing

Energy Technology Data Exchange (ETDEWEB)

Branch, Shirmir D.; Lines, Amanda M.; Lynch, John A.; Bello, Job M.; Heineman, William R.; Bryan, Samuel A.

2017-07-03

The electrochemical and spectroelectrochemical applications of an optically transparent thin film electrode chip are investigated. The working electrode is composed of indium tin oxide (ITO); the counter and quasi-reference electrodes are composed of platinum. The stability of the platinum quasi-reference electrode is modified by coating it with a planar, solid state Ag/AgCl layer. The Ag/AgCl reference is characterized with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Open circuit potential measurements indicate that the potential of the planar Ag/AgCl electrode varies a maximum of 20 mV over four days. Cyclic voltammetry measurements show that the electrode chip is comparable to a standard electrochemical cell. Randles-Sevcik analysis of 10 mM K3[Fe(CN)6] in 0.1 M KCl using the electrode chip shows a diffusion coefficient of 1.59 × 10-6 cm2/s, in comparison to the standard electrochemical cell value of 2.38 × 10-6 cm2/s. By using the electrode chip in an optically transparent thin layer electrode (OTTLE), the spectroelectrochemical modulation of [Ru(bpy)3]2+ florescence was demonstrated, achieving a detection limit of 36 nM.

Electroactive cytochrome P450BM3 cast polyion films on graphite electrodes

International Nuclear Information System (INIS)

Pardo-Jacques, Aurelie; Basseguy, Regine; Bergel, Alain

2006-01-01

Films of electrochemically active cytochrome P450 BM 3 were constructed on graphite electrodes using alternate assembly with polyethyleneimine (PEI). The original layer-by-layer adsorption method was slightly modified here to form so-called 'cast polyion' films. The cast polyion films were elaborated by immobilizing two successive layers of PEI and protein in very large excess with respect to a monolayer, without any intermediate washing step. Following the immobilization steps by SEM showed that uniform films of a few micrometers were deposited on the graphite surface. The electrochemically activity of the immobilized cytP450 was tested with regard to the reduction of oxygen and the one-electron reduction of the heme. Cyclic voltammetry indicated surface concentration of electrochemically active cytP450 around 0.6nmol/cm 2 , which corresponded to 5% of the total amount of protein that was consumed by the immobilisation process. Adapting the procedure to a graphite felt electrode with the view of scaling up porous electrodes for large scale synthesis increased the concentration to 0.9nmol/cm 2 . Cast polyion films may represent a simple technique to immobilize high amount of electrochemically active protein, keeping the advantage of the electrostatic interactions of the regular layer-by-layer method

Characterization and electrochemical studies of Nafion/nano-TiO2 film modified electrodes

International Nuclear Information System (INIS)

Yuan Shuai; Hu Shengshui

2004-01-01

A nano-TiO 2 film from stable aqueous dispersion has been modified on a glassy carbon electrode (GCE), and was characterized by scanning electron microscopy (SEM) and surface-enhanced Raman spectroscopy (SERS). This nanostructured film exhibits an ability to improve the electron-transfer rate between electrode and dopamine (DA), and electrocatalyze the redox of DA. The electrocatalytical behavior of DA was examined by cyclic voltammetry (CV). Combined with Nafion, the bilayer-modified electrode (N/T/GCE) gives a sensitive voltammetric response of DA regardless of excess ascorbic acid (AA). Electrochemical impedance spectroscopy (EIS) at a fixed potential was performed at variously treated GCEs. The mechanism of the electrode reaction of DA at N/T/GCE and the equivalent circuits of different GCEs have been proposed

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

International Nuclear Information System (INIS)

Feng, Xiaojuan; Shi, Yanlong; Jin, Shuping

2015-01-01

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.

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

Energy Technology Data Exchange (ETDEWEB)

Feng, Xiaojuan, E-mail: cherry-820@163.com; Shi, Yanlong; Jin, Shuping

2015-10-30

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{sup −1} at 0.3 A g{sup −1} current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g{sup −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.

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

KAUST Repository

Jana, Partha Sarathi; Katuri, Krishna; Kavanagh, Paul; Kumar, Amit Ravi Pradeep; Leech, Dó nal

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.

Prussian blue-modified nanoporous gold film electrode for amperometric determination of hydrogen peroxide.

Science.gov (United States)

Ghaderi, Seyran; Mehrgardi, Masoud Ayatollahi

2014-08-01

In this manuscript, the electrocatalytic reduction of hydrogen peroxides on Prussian blue (PB) modified nanoporous gold film (NPGF) electrode is described. The PB/NPGF is prepared by simple anodizing of a smooth gold film followed by PB film electrodeposition method. The morphology of the PB/NPGF electrode is characterized using scanning electron microscopy (SEM). The effect of solution pH and the scan rates on the voltammetric responses of hydrogen peroxide have also been examined. The amperometric determination of H2O2 shows two linear dynamic responses over the concentration range of 1μM-10μM and 10μM-100μM with a detection limit of 3.6×10(-7)M. Furthermore, this electrode demonstrated good stability, repeatability and selectivity remarkably. Copyright © 2014 Elsevier B.V. All rights reserved.

Microstructure of thin film platinum electrodes on yttrium stabilized zirconia prepared by sputter deposition

Energy Technology Data Exchange (ETDEWEB)

Toghan, Arafat, E-mail: arafat.toghan@pci.uni-hannover.de [Institute of Physical Chemistry and Electrochemistry, Leibniz University of Hannover, Callinstrasse 3-3a, D-30167 Hannover (Germany); Khodari, M. [Chemistry Department, Faculty of Science, South Valley University, Qena, 83523 (Egypt); Steinbach, F.; Imbihl, R. [Institute of Physical Chemistry and Electrochemistry, Leibniz University of Hannover, Callinstrasse 3-3a, D-30167 Hannover (Germany)

2011-09-01

(111) oriented thin film Pt electrodes were prepared on single crystals of yttrium-stabilized zirconia (YSZ) by sputter deposition of platinum. The electrodes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and by profilometry. SEM images of the as-sputtered platinum film show a compact amorphous Pt film covering uniformly the substrate. Upon annealing at 1123 K, gaps and pores at the interface develop leading to a partial dewetting of the Pt film. Increasing the annealing temperature to 1373 K transforms the polycrystalline Pt film into single crystalline grains exhibiting a (111) orientation towards the substrate.

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

International Nuclear Information System (INIS)

Arai, Takahiro; Furuya, Masahiro; Kanai, Taizo

2010-01-01

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)

Selective oxidation of serotonin and norepinephrine over eriochrome cyanine R film modified glassy carbon electrode

Energy Technology Data Exchange (ETDEWEB)

Yao Hong; Li Shaoguang [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China); Tang Yuhai [Institute of Analytical Sciences, Xi' an Jiaotong University, Xi' an 710061 (China); Chen Yan [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China); Chen Yuanzhong [Fujian Institute of Hematology, The Affiliated Union Hospital of Fujian Medical University, Fuzhou 350001 (China)], E-Mail: chenyz@pub3.fz.fj.cn; Lin Xinhua [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China)], E-mail: xhlin1963@sin.com

2009-08-01

A novel ECR-modified electrode is fabricated by electrodeposition of Eriochrome Cyanine R (ECR) at a glassy carbon (GC) electrode by cyclic voltammetry (CV) in double-distilled water. The characterization of the ECR film modified electrode is carried out by atomic force microscopy (AFM), infrared spectra (IR), spectroelectrochemistry and cyclic voltammetry. The results show that a slightly heterogeneous film formed on the surface of the modified electrode, and the calculated surface concentration of ECR is 2 x 10{sup -10} mol/cm{sup -2}. The ECR film modified GC electrode shows excellent electrocatalytic activities toward the oxidation of serotonin (5-HT) and norepinephrine (NE). Furthermore, the modified electrode can separately detect 5-HT and NE, even in the presence of 200-fold concentration of ascorbic acid (AA) and 25-fold concentration of uric acid (UA). Using differential pulse voltammetry (DPV), the peak currents of 5-HT and NE recorded in pH 7 solution are linearly dependent on their concentrations in the range of 0.05-5 {mu}M and 2-50 {mu}M, respectively. The limits of detection are 0.05 and 1.5 {mu}M for 5-HT and NE, respectively. The ECR film modified electrode can be stored stable for at least 1 week in 0.05 M PBS (pH 7) at 4 {sup o}C in a refrigerator. Owing to its excellent selectivity and sensitivity, the modified electrode could provide a promising tool for the simultaneous determination of 5-HT and NE in complex biosamples.

Photoelectrochemistry of copper(I) acetylide films electrodeposited onto copper electrodes

Energy Technology Data Exchange (ETDEWEB)

Zotti, G.; Cattarin, S.; Mengoli, G.; Fleischmann, M.; Peter, L.M.

1986-01-01

Films of copper acetylide (Cu/sub 2/C/sub 2/) were grown electrochemically on copper and characterized by transmittance and reflectance techniques. The photoelectrochemical properties of the filmed electrodes in alkaline solution indicate that Cu/sub 2/C/sub 2/ behaves as a p-type semiconducting material (1.5 eV band gap). The photocurrents depend on film thickness and aging and high resistivity or recombination losses limit the quantum yield to some 4% for thicknesses of practical importance (250 nm).

Carbon black nanoparticles film electrode prepared by using substrate-induced deposition approach

Energy Technology Data Exchange (ETDEWEB)

Svegl, Irena Grabec; Bele, Marjan [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia); Ogorevc, Bozidar [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia)], E-mail: bogorevc@ki.si

2008-11-03

A new type of carbon film electrode, composed of a thin layer of tightly packed carbon black (CB) nanoparticles deposited onto a gelatin-covered indium tin oxide/glass support using the surface-induced deposition (SID) approach, is presented. Some parameters of the novel SID method were optimized and the surface image and functionalization of the investigated carbon black film electrode (CBFE) was inspected by employing scanning electron microscopy and infrared spectroscopy. A cyclic voltammetry (CV) study was conducted in which the electron-transfer kinetics and CBFE interfacial characteristics were evaluated employing several selected reference redox systems, such as [Ru(NH{sub 3}){sub 6}]{sup 3+/2+}, [Fe(CN){sub 6}]{sup 3-/4-} and Fe{sup 3+/2+} in aqueous, and ferrocene/ferrocenium in acetonitrile media. CV recordings were also performed in order to compare the electrochemical behavior of the CBFE with that of some well-known and established bare carbon-based electrodes. In order to confirm the validity of the CB film preparation method, the electroanalytical performance of the proposed CBFE was examined by carrying out linear sweep voltammetry of ascorbic acid (AA), anodic stripping square-wave voltammetry of Cu(II) in acidic medium, and amperometric measurements of hydrogen peroxide under flow injection conditions. The sensing characteristics of the novel carbon film electrode, demonstrated in this preliminary study, comprise: (i) a wide working potential window ranging from +1.0 to -1.3 V (depending on the solution pH), (ii) a wide applicable pH range (at least from 2 to 12), (iii) low voltammetric background (<5 {mu}A cm{sup -2}), (iv) a satisfactory linear voltammetric and amperometric response (r{sup 2} > 0.99) to various analytes, (v) good reproducibility (for example, r.s.d. of 2% in amperometric detection of H{sub 2}O{sub 2} and r.s.d. of 8.5% for electrode-to-electrode CV runs), and (vi) stable and fast current response (at least 100 CV runs with

Transparent and conductive electrodes by large-scale nano-structuring of noble metal thin-films

DEFF Research Database (Denmark)

Linnet, Jes; Runge Walther, Anders; Wolff, Christian

2018-01-01

grid, and nano-wire thin-films. The indium and carbon films do not match the chemical stability nor the electrical performance of the noble metals, and many metal films are not uniform in material distribution leading to significant surface roughness and randomized transmission haze. We demonstrate...... solution-processed masks for physical vapor-deposited metal electrodes consisting of hexagonally ordered aperture arrays with scalable aperture-size and spacing in an otherwise homogeneous noble metal thin-film that may exhibit better electrical performance than carbon nanotube-based thin-films...... for equivalent optical transparency. The fabricated electrodes are characterized optically and electrically by measuring transmittance and sheet resistance. The presented methods yield large-scale reproducible results. Experimentally realized thin-films with very low sheet resistance, Rsh = 2.01 ± 0.14 Ω...

Rhenium Alloys as Ductile Substrates for Diamond Thin-Film Electrodes.

Science.gov (United States)

Halpern, Jeffrey M; Martin, Heidi B

2014-02-01

Molybdenum-rhenium (Mo/Re) and tungsten-rhenium (W/Re) alloys were investigated as substrates for thin-film, polycrystalline boron-doped diamond electrodes. Traditional, carbide-forming metal substrates adhere strongly to diamond but lose their ductility during exposure to the high-temperature (1000°C) diamond, chemical vapor deposition environment. Boron-doped semi-metallic diamond was selectively deposited for up to 20 hours on one end of Mo/Re (47.5/52.5 wt.%) and W/Re (75/25 wt.%) alloy wires. Conformal diamond films on the alloys displayed grain sizes and Raman signatures similar to films grown on tungsten; in all cases, the morphology and Raman spectra were consistent with well-faceted, microcrystalline diamond with minimal sp 2 carbon content. Cyclic voltammograms of dopamine in phosphate-buffered saline (PBS) showed the wide window and low baseline current of high-quality diamond electrodes. In addition, the films showed consistently well-defined, dopamine electrochemical redox activity. The Mo/Re substrate regions that were uncoated but still exposed to the diamond-growth environment remained substantially more flexible than tungsten in a bend-to-fracture rotation test, bending to the test maximum of 90° and not fracturing. The W/Re substrates fractured after a 27° bend, and the tungsten fractured after a 21° bend. Brittle, transgranular cleavage fracture surfaces were observed for tungsten and W/Re. A tension-induced fracture of the Mo/Re after the prior bend test showed a dimple fracture with a visible ductile core. Overall, the Mo/Re and W/Re alloys were suitable substrates for diamond growth. The Mo/Re alloy remained significantly more ductile than traditional tungsten substrates after diamond growth, and thus may be an attractive metal substrate for more ductile, thin-film diamond electrodes.

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.

Polymyxin-coated Au and carbon nanotube electrodes for stable [NiFe]-hydrogenase film voltammetry.

NARCIS (Netherlands)

Hoeben, F.J.M.; Heller, I.; Albracht, S.P.J.; Dekker, C.; Lemay, S.G.; Heering, H.A.

2008-01-01

We report on the use of polymyxin (PM), a cyclic cationic lipodecapeptide, as an electrode modifier for studying protein film voltammetry (PFV) on Au and single-walled carbon nanotube (SWNT) electrodes. Pretreating the electrodes with PM allows for the subsequent immobilization of an active

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

International Nuclear Information System (INIS)

Zhao, Wanyu; Fu, Wuyou; Chen, Jingkuo; Li, Huayang; Bala, Hari; Wang, Xiaodong; Sun, Guang; Cao, Jianliang; Zhang, Zhanying

2015-01-01

The composite thin film electrodes were prepared with one-dimensional (1D) TiO 2 -B nanotubes (NTs) and zero-dimensional TiO 2 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 TiO 2 NPs electrodes by rational tuning the weight ratio of TiO 2 -B NTs and TiO 2 NPs. When the weight ratio of TiO 2 -B NTs in the NTs/NPs composite thin film electrodes increased, the density of states and recombination rate decreased. The 1D structure of TiO 2 -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 TiO 2 -B NTs and the high surface area of TiO 2 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

Examining the validity of Stoney-equation for in-situ stress measurements in thin film electrodes using a large-deformation finite-element procedure

Science.gov (United States)

Wen, Jici; Wei, Yujie; Cheng, Yang-Tse

2018-05-01

During the lithiation and delithiation of a thin film electrode, stress in the electrode is deduced from the curvature change of the film using the Stoney equation. The accuracy of such a measurement is conditioned on the assumptions that (a) the mechanical properties of the electrode remain unchanged during lithiation and (b) small deformation holds. Here, we demonstrate that the change in elastic properties can influence the measurement of the stress in thin film electrodes. We consider the coupling between diffusion and deformation during lithiation and delithiation of thin film electrodes and implement the constitutive behavior in a finite-deformation finite element procedure. We demonstrate that both the variation in elastic properties in thin film electrodes and finite-deformation during lithiation and delithiation would challenge the applicability of the Stoney-equation for in-situ stress measurements of thin film electrodes.

Graphene-based electrodes for enhanced organic thin film transistors based on pentacene.

Science.gov (United States)

Basu, Sarbani; Lee, Mu Chen; Wang, Yeong-Her

2014-08-21

This paper presents 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and pentacene-based organic thin film transistors (OTFTs) with monolayer graphene source-drain (S-D) electrodes. The electrodes are patterned using conventional photolithographic techniques combined with reactive ion etching. The monolayer graphene film grown by chemical vapor deposition on Cu foil was transferred on a Si dioxide surface using a polymer-supported transfer method to fabricate bottom-gate, bottom-contact OTFTs. The pentacene OTFTs with graphene S-D contacts exhibited superior performance with a mobility of 0.1 cm(2) V(-1) s(-1) and an on-off ratio of 10(5) compared with OTFTs with Au-based S-D contacts, which had a mobility of 0.01 cm(2) V(-1) s(-1) and an on-off ratio of 10(3). The crystallinity, grain size, and microscopic defects (or the number of layers of graphene films) of the TIPS-pentacene/pentacene films were analyzed by X-ray diffraction spectroscopy, atomic force microscopy, and Raman spectroscopy, respectively. The feasibility of using graphene as an S-D electrode in OTFTs provides an alternative material with high carrier injection efficiency, chemical stability, and excellent interface properties with organic semiconductors, thus exhibiting improved device performance of C-based electronic OTFTs at a reduced cost.

Characterization of Pb(Zr, Ti)O3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes

International Nuclear Information System (INIS)

Lee, Hee-Chul; Lee, Won-Jong

2002-01-01

Structural and electrical characteristics of Pb(Zr, Ti)O 3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO 2 , and Pt/IrO 2 ) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO 2 electrode contain a large amount of PbO x phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO 2 , and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO 2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics

Silicon-based thin films as bottom electrodes in chalcogenide nonvolatile memories

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung-Yun [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)], E-mail: seungyun@etri.re.kr; Yoon, Sung-Min; Choi, Kyu-Jeong; Lee, Nam-Yeal; Park, Young-Sam; Ryu, Sang-Ouk; Yu, Byoung-Gon; Kim, Sang-Hoon; Lee, Sang-Heung [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)

2007-10-31

The effect of the electrical resistivity of a silicon-germanium (SiGe) thin film on the phase transition in a GeSbTe (GST) chalcogenide alloy and the manufacturing aspect of the fabrication process of a chalcogenide memory device employing the SiGe film as bottom electrodes were investigated. While p-type SiGe bottom electrodes were formed using in situ doping techniques, n-type ones could be made in a different manner where phosphorus atoms diffused from highly doped silicon underlayers to undoped SiGe films. The p-n heterojunction did not form between the p-type GST and n-type SiGe layers, and the semiconduction type of the SiGe alloys did not influence the memory device switching. It was confirmed that an optimum resistivity value existed for memory operation in spite of proportionality of Joule heating to electrical resistivity. The very high resistivity of the SiGe film had no effect on the reduction of reset current, which might result from the resistance decrease of the SiGe alloy at high temperatures.

Ti Porous Film-Supported NiCo₂S₄ Nanotubes Counter Electrode for Quantum-Dot-Sensitized Solar Cells.

Science.gov (United States)

Deng, Jianping; Wang, Minqiang; Song, Xiaohui; Yang, Zhi; Yuan, Zhaolin

2018-04-17

In this paper, a novel Ti porous film-supported NiCo₂S₄ nanotube was fabricated by the acid etching and two-step hydrothermal method and then used as a counter electrode in a CdS/CdSe quantum-dot-sensitized solar cell. Measurements of the cyclic voltammetry, Tafel polarization curves, and electrochemical impedance spectroscopy of the symmetric cells revealed that compared with the conventional FTO (fluorine doped tin oxide)/Pt counter electrode, Ti porous film-supported NiCo₂S₄ nanotubes counter electrode exhibited greater electrocatalytic activity toward polysulfide electrolyte and lower charge-transfer resistance at the interface between electrolyte and counter electrode, which remarkably improved the fill factor, short-circuit current density, and power conversion efficiency of the quantum-dot-sensitized solar cell. Under illumination of one sun (100 mW/cm²), the quantum-dot-sensitized solar cell based on Ti porous film-supported NiCo₂S₄ nanotubes counter electrode achieved a power conversion efficiency of 3.14%, which is superior to the cell based on FTO/Pt counter electrode (1.3%).

Nano-sized copper tungstate thin films as positive electrodes for rechargeable Li batteries

International Nuclear Information System (INIS)

Li Chilin; Fu Zhengwen

2008-01-01

Nano-sized CuWO 4 thin films have been fabricated by radio-frequency (R.F.) sputtering deposition, and are used as positive electrode with both LiClO 4 liquid electrolyte and LiPON solid electrolyte in rechargeable lithium batteries. An initial discharge capacity of 192 and 210 mAh/g is obtainable for CuWO 4 film electrode with and without coated LiPON in liquid electrolyte, respectively. An all-solid-state cell with Li/LiPON/CuWO 4 layers shows a high-volume rate capacity of 145 μAh/cm 2 μm in first discharge, and overcomes the unfavorable electrochemical degradation observed in liquid electrolyte system. A two-step reactive mechanism is investigated by both transmission electron microscopy and selected area electron diffraction techniques. Apart from the extrusion and injection of Cu 2+ /Cu 0 , additional capacity can be achieved by the reversible reactivity of (WO 4 ) 2- framework. The chemical diffusion coefficients of Li intercalation/deintercalation are estimated by cyclic voltammetry. Nano-CuWO 4 thin film is expected to be a promising positive electrode material for high-performance rechargeable thin-film lithium batteries

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

International Nuclear Information System (INIS)

Xin-Yi, Wen; Jun, Yu; Yun-Bo, Wang; Wen-Li, Zhou; Jun-Xiong, Gao; Xiao-Hui, Chu

2008-01-01

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/cm 2 (81.3kV/cm) and 36.9μC/cm 2 (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. (cross-disciplinary physics and related areas of science and technology)

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

International Nuclear Information System (INIS)

Ong, Hui-Yng; Shrestha, Milan; Lau, Gih-Keong

2015-01-01

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

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.

Mediatorless bioelectrocatalysis of dioxygen reduction at indium-doped tin oxide (ITO) and ITO nanoparticulate film electrodes

Energy Technology Data Exchange (ETDEWEB)

Rozniecka, Ewa; Jonsson-Niedziolka, Martin; Sobczak, Janusz W. [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warszawa (Poland); Opallo, Marcin, E-mail: mopallo@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warszawa (Poland)

2011-10-01

Highlights: > We introduced ITO nanoparticulate films for enzyme immobilization. > The material promotes mediatorless bioelectrocatalysis towards dioxygen reduction. > The electrocatalytical current increase with the thickness of nanoparticulate film. > There is no difference in electrocatalytic current in the presence or absence of mediator. > The stability of the electrode can be improved by crosslinking of the enzyme with bovine serum albumin and glutaraldehyde. - Abstract: Bilirubin oxidase was immobilised on ITO electrodes: bare or covered by ITO nanoparticulate film. The latter material was obtained by immersion and withdrawal of the substrate into ITO nanoparticles suspension. Formation of a protein deposit was confirmed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The electrode surface is covered by a protein film in the form of globular aggregates and it exhibits mediatorless electrocatalytic activity towards dioxygen reduction to water at pH 4.8. Modification of the electrode with ITO particles increases its catalytic activity about ten times up to 110 {mu}A cm{sup -2} seen for electrodes prepared by twelve immersion and withdrawal steps into ITO nanoparticle suspension. The catalytic activity is almost unaffected by addition of mediator to solution. The stability of the electrodes is increased by cross-linking of the enzyme with bovine serum albumin and glutaraldehyde. This electrode was applied as biocathode in a zinc-dioxygen battery operating in 0.1 mol dm{sup -3} McIlvaine buffer (pH 4.8).

Mediatorless bioelectrocatalysis of dioxygen reduction at indium-doped tin oxide (ITO) and ITO nanoparticulate film electrodes

International Nuclear Information System (INIS)

Rozniecka, Ewa; Jonsson-Niedziolka, Martin; Sobczak, Janusz W.; Opallo, Marcin

2011-01-01

Highlights: → We introduced ITO nanoparticulate films for enzyme immobilization. → The material promotes mediatorless bioelectrocatalysis towards dioxygen reduction. → The electrocatalytical current increase with the thickness of nanoparticulate film. → There is no difference in electrocatalytic current in the presence or absence of mediator. → The stability of the electrode can be improved by crosslinking of the enzyme with bovine serum albumin and glutaraldehyde. - Abstract: Bilirubin oxidase was immobilised on ITO electrodes: bare or covered by ITO nanoparticulate film. The latter material was obtained by immersion and withdrawal of the substrate into ITO nanoparticles suspension. Formation of a protein deposit was confirmed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The electrode surface is covered by a protein film in the form of globular aggregates and it exhibits mediatorless electrocatalytic activity towards dioxygen reduction to water at pH 4.8. Modification of the electrode with ITO particles increases its catalytic activity about ten times up to 110 μA cm -2 seen for electrodes prepared by twelve immersion and withdrawal steps into ITO nanoparticle suspension. The catalytic activity is almost unaffected by addition of mediator to solution. The stability of the electrodes is increased by cross-linking of the enzyme with bovine serum albumin and glutaraldehyde. This electrode was applied as biocathode in a zinc-dioxygen battery operating in 0.1 mol dm -3 McIlvaine buffer (pH 4.8).

Effects of crystalline quality and electrode material on fatigue in Pb(Zr,Ti)O3 thin film capacitors

Science.gov (United States)

Lee, J.; Johnson, L.; Safari, A.; Ramesh, R.; Sands, T.; Gilchrist, H.; Keramidas, V. G.

1993-07-01

Pb(Zr(0.52)Ti(0.48))O3 (PZT)/Y1Ba2Cu3O(x) (YBCO) heterostructures were grown by pulsed laser deposition, in which PZT films were epitaxial, highly oriented, or polycrystalline. These PZT films were obtained by varying the deposition temperature from 550 to 760 C or by using various substrates such as SrTiO3 (100), MgO (100), and r-plane sapphire. PZT films with Pt top electrodes exhibited large fatigue with 35-50 percent loss of the remanent polarization after 10 exp 9 cycles, depending on the crystalline quality. Polycrystalline films showed better fatigue resistance than epitaxial or highly oriented films. However, PZT films with both top and bottom YBCO electrodes had significantly improved fatigue resistance for both epitaxial and polycrystalline films. Electrode material seems to be a more important parameter in fatigue than the crystalline quality of the PZT films.

Effects of mesoscopic poly(3,4-ethylenedioxythiophene) films as counter electrodes for dye-sensitized solar cells

International Nuclear Information System (INIS)

Lee, Kun-Mu; Chiu, Wei-Hao; Wei, Hung-Yu; Hu, Chih-Wei; Suryanarayanan, Vembu; Hsieh, Weng-Feng; Ho, Kuo-Chuan

2010-01-01

Counter electrode coated with chemically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) in a dye-sensitized solar cell (DSSC) was studied. The surface morphology and the nature of I - /I 3 - redox reaction based on PEDOT film were investigated using Atomic Force Microscopy and Cyclic Voltammetry, respectively. The performance of the DSSCs containing the PEDOT coated electrode was compared with sputtered-Pt electrode. We found that the root mean square roughness decreases and conductivity increases as the molar ratio of imidazole (Im)/EDOT in the PEDOT film increases. The DSSC containing the PEDOT coated on fluorine doped tin oxide glass with Im/EDOT molar ratio of 2.0, showed a conversion efficiency of 7.44% compared to that with sputtered-Pt electrode (7.77%). The high photocurrents were attributed to the large effective surface area of the electrode material resulting in good catalytic properties for I 3 - reduction. Therefore, the incorporation of a multi-walled carbon nanotube (MWCNT) in the PEDOT film, coated on various substrates was also investigated. The DSSC containing the PEDOT films with 0.6 wt.% of MWCNT on stainless steel as counter electrode had the best cell performance of 8.08% with short-circuit current density, open-circuit voltage and fill factor of 17.00 mA cm -2 , 720 mV and 0.66, respectively.

Effects of mesoscopic poly(3,4-ethylenedioxythiophene) films as counter electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Kun-Mu, E-mail: d93549007@ntu.edu.t [Photovoltaics Technology Center, Industrial Technology Research Institute, Chutung, Hsinchu 31040, Taiwan (China); Chiu, Wei-Hao [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Road, Hsinchu 30050, Taiwan (China); Wei, Hung-Yu; Hu, Chih-Wei [Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Suryanarayanan, Vembu [Electro Organic Division, Central Electrochemical Research Institute, Karaikudi 630 006 (India); Hsieh, Weng-Feng [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Road, Hsinchu 30050, Taiwan (China); Ho, Kuo-Chuan [Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2010-01-01

Counter electrode coated with chemically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) in a dye-sensitized solar cell (DSSC) was studied. The surface morphology and the nature of I{sup -}/I{sub 3}{sup -} redox reaction based on PEDOT film were investigated using Atomic Force Microscopy and Cyclic Voltammetry, respectively. The performance of the DSSCs containing the PEDOT coated electrode was compared with sputtered-Pt electrode. We found that the root mean square roughness decreases and conductivity increases as the molar ratio of imidazole (Im)/EDOT in the PEDOT film increases. The DSSC containing the PEDOT coated on fluorine doped tin oxide glass with Im/EDOT molar ratio of 2.0, showed a conversion efficiency of 7.44% compared to that with sputtered-Pt electrode (7.77%). The high photocurrents were attributed to the large effective surface area of the electrode material resulting in good catalytic properties for I{sub 3}{sup -} reduction. Therefore, the incorporation of a multi-walled carbon nanotube (MWCNT) in the PEDOT film, coated on various substrates was also investigated. The DSSC containing the PEDOT films with 0.6 wt.% of MWCNT on stainless steel as counter electrode had the best cell performance of 8.08% with short-circuit current density, open-circuit voltage and fill factor of 17.00 mA cm{sup -2}, 720 mV and 0.66, respectively.

Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

International Nuclear Information System (INIS)

Liu, Zhiming; Wang, Xuefeng; Wu, Wenjian; Li, Mei

2015-01-01

Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10 −9 M after being loaded with CaM proteins. (paper)

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...... recorded through the LSM thin film electrodes and revealed distinct compositional changes throughout the electrodes (Figure 2). The electrode elements and impurities separated into distinct layers that were more pronounced for the stronger applied polarisations. The mechanism behind this separation...

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

2016-09-22

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.

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.

High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode

Science.gov (United States)

Mei, Xiaoguang; Cho, Swee Jen; Fan, Benhu; Ouyang, Jianyong

2010-10-01

High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode

International Nuclear Information System (INIS)

Mei Xiaoguang; Cho, Swee Jen; Fan Benhu; Ouyang Jianyong

2010-01-01

High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

Science.gov (United States)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-10-01

A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 °C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 × 10-4 Ω cm with the carrier concentration of 1.65 × 1021 cm-3 and Hall mobility of 11.3 cm2/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Chemically fabricated LiFePO{sub 4} thin film electrode for transparent batteries and electrochromic devices

Energy Technology Data Exchange (ETDEWEB)

Béléké, Alexis B. [Institut de recherche d’Hydro-Québec, 1800 Boul. Lionel-Boulet, Varennes, QC J3X 1S3 (Canada); Department of Mining and Materials Engineering, McGill University, M.H. Wong Building, 3610 rue University, Montréal, QC H3A 2B2 (Canada); Faure, Cyril [Institut de recherche d’Hydro-Québec, 1800 Boul. Lionel-Boulet, Varennes, QC J3X 1S3 (Canada); Röder, Manuel [Center for Applied Electrochemistry, Fraunhofer Institute for Silicate Research, Neunerplatz 2, 97083 Würzburg (Germany); Hovington, Pierre [Institut de recherche d’Hydro-Québec, 1800 Boul. Lionel-Boulet, Varennes, QC J3X 1S3 (Canada); Posset, Uwe [Center for Applied Electrochemistry, Fraunhofer Institute for Silicate Research, Neunerplatz 2, 97083 Würzburg (Germany); Guerfi, Abdelbast [Institut de recherche d’Hydro-Québec, 1800 Boul. Lionel-Boulet, Varennes, QC J3X 1S3 (Canada); Zaghib, Karim, E-mail: zaghib.karim@ireq.ca [Institut de recherche d’Hydro-Québec, 1800 Boul. Lionel-Boulet, Varennes, QC J3X 1S3 (Canada)

2016-12-15

Graphical abstract: Simplified diagram of the novel sol-gel approach of preparation of colorless and transparent LiFePO{sub 4} thin film electrode. - Highlights: • Novel sol-gel synthesis of colorless LFP thin film electrode for transparent Li-ion battery. • High performance of the electrode at various current densities: 5, 10, 20, 50 and 100 μA/cm{sup 2}. • LFP nanoparticles exhibit an excellent electro-activity. • Colorless LFP thin film shows a transmittance above 80% versus FTO. • Higher transmittance of LFP electrode a potential candidate for electrochromic devices. - Abstract: We report a new sol-gel approach of synthesis of LiFePO{sub 4} (LFP) thin film and its application as cathode materials for transparent Li-ion battery in half-cell configuration. LFP thin films were obtained from an alcoholic colloidal suspension of iron acetylacetonate (Fe(AcAc){sub 3}) and aqueous lithium dihydrogen phosphate (LiH{sub 2}PO{sub 4}) deposited on fluorine tin oxide (FTO) glass substrate, followed by heating at 450 °C under nitrogen gas for 1 h. X-ray diffraction (XRD) confirmed that the LFP films have an orthorhombic crystal system with space group Pnma (62). Scanning electron microscopy (SEM) shows spherical LFP nanoparticles aggregates homogenously deposited all over the surface of FTO substrate containing 3-D open pores. The electrochemical behaviors of thin film vs Li/Li{sup +} cell were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The cycle life was evaluated by running 1000 cycles of charge-discharge at a current density of 20 μA/cm{sup 2}. The transmission spectra reveal 85–90% of transparency versus FTO as reference, which makes it a potential candidate as a complementary electrode in electrochromic devices (ECDs).

Catalytic EC′ reaction at a thin film modified electrode

International Nuclear Information System (INIS)

Gerbino, Leandro; Baruzzi, Ana M.; Iglesias, Rodrigo A.

2013-01-01

Numerical simulations of cyclic voltammograms corresponding to a catalytic EC′ reaction taking place at a thin film modified electrode are performed by way of finite difference method. Besides considering the chemical kinetic occurring inside the thin film, the model takes into account the different diffusion coefficients for each species at each of the involved phases, i.e. the thin film layer and bulk solution. The theoretical formulation is given in terms of dimensionless model parameters but a brief discussion of each of these parameters and their relationship to experimental variables is presented. Special emphasis is given to the use of working curve characteristics to quantify diffusion coefficient, homogeneous kinetic constant and thickness of the thin layer in a real system. Validation of the model is made by comparison of experimental results corresponding to the electron charge transfer of Ru(NH 3 ) 6 3+ /Ru(NH 3 ) 6 2+ hemi-couple at a thin film of a cross-linked chitosan film containing an immobilized redox dye

Voltammetric Response of Alizarin Red S-Confined Film-Coated Electrodes to Diol and Polyol Compounds: Use of Phenylboronic Acid-Modified Poly(ethyleneimine) as Film Component.

Science.gov (United States)

Takahashi, Shigehiro; Suzuki, Iwao; Ojima, Takuto; Minaki, Daichi; Anzai, Jun-Ichi

2018-01-22

Alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of phenylboronic acid-modified poly(ethyleneimine) (PBA-PEI) and carboxymethylcellulose (CMC) to study the voltammetric response to diol and polyol compounds. The LbL film-coated gold (Au) electrode and quartz slide were immersed in an ARS solution to uptake ARS into the film. UV-visible absorption spectra of ARS-confined LbL film suggested that ARS formed boronate ester (ARS-PBS) in the film. The cyclic voltammetry of the ARS-confined LbL film-coated electrodes exhibited oxidation peaks at -0.50 and -0.62 V, which were ascribed to the oxidation reactions of ARS-PBS and free ARS, respectively, in the LbL film. The peak current at -0.62 V increased upon the addition of diol or polyol compounds such as L-dopa, glucose, and sorbitol into the solution, depending on the concentration, whereas the peak current at -0.50 V decreased. The results suggest a possible use of ARS-confined PBA-PEI/CMC LbL film-coated Au electrodes for the construction of voltammetric sensors for diol and polyol compounds.

Layered Ni(OH)2-Co(OH)2 films prepared by electrodeposition as charge storage electrodes for hybrid supercapacitors.

Science.gov (United States)

Nguyen, Tuyen; Boudard, Michel; Carmezim, M João; Montemor, M Fátima

2017-01-04

Consecutive layers of Ni(OH) 2 and Co(OH) 2 were electrodeposited on stainless steel current collectors for preparing charge storage electrodes of high specific capacity with potential application in hybrid supercapacitors. Different electrodes were prepared consisting on films of Ni(OH) 2 , Co(OH) 2 , Ni 1/2 Co 1/2 (OH) 2 and layered films of Ni(OH) 2 on Co(OH) 2 and Co(OH) 2 on Ni(OH) 2 to highlight the advantages of the new architecture. The microscopy studies revealed the formation of nanosheets in the Co(OH) 2 films and of particles agglomerates in the Ni(OH) 2 films. Important morphological changes were observed in the double hydroxides films and layered films. Film growth by electrodeposition was governed by instantaneous nucleation mechanism. The new architecture composed of Ni(OH) 2 on Co(OH) 2 displayed a redox response characterized by the presence of two peaks in the cyclic voltammograms, arising from redox reactions of the metallic species present in the layered film. These electrodes revealed a specific capacity of 762 C g -1 at the specific current of 1 A g -1 . The hybrid cell using Ni(OH) 2 on Co(OH) 2 as positive electrode and carbon nanofoam paper as negative electrode display specific energies of 101.3 W h g -1 and 37.8 W h g -1 at specific powers of 0.2 W g -1 and 2.45 W g -1 , respectively.

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

International Nuclear Information System (INIS)

Kymakis, E.; Stratakis, E.; Stylianakis, M.M.; Koudoumas, E.; Fotakis, C.

2011-01-01

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-C 61 -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.

Transparent electrode designs based on optimal nano-patterning of metallic films

KAUST Repository

Catrysse, Peter B.

2010-09-10

Transparent conductive electrodes are critical to the operation of optoelectronic devices, such as photovoltaic cells and light emitting diodes. Effective electrodes need to combine excellent electrical and optical properties. Metal oxides, such as indium tin oxide, are commonly used. There is substantial interest in replacing them, however, motivated by practical problems and recent discoveries regarding the optics of nano-patterned metals. When designing nano-patterned metallic films for use as electrodes, one needs to account for both optical and electrical properties. In general, it is insufficient to optimize nano-structured films based upon optical properties alone, since structural variations will also affect the electrical properties. In this work, we investigate the need for simultaneous optical and electrical performance by analyzing the optical properties of a class of nano-patterned metallic electrodes that is obtained by a constant-sheet-resistance transformation. Within such a class the electrical and optical properties can be separated, i.e., the sheet resistance can be kept constant and the transmittance can be optimized independently. For simple one-dimensional periodic patterns with constant sheet-resistance, we find a transmission maximum (polarization-averaged) when the metal sections are narrow (< 40 nm, ~ 10% metal fill-factor) and tall (> 100 nm). Our design carries over to more complex two-dimensional (2D) patterns. This is significant as there are no previous reports regarding numerical studies on the optical and electrical properties of 2D nano-patterns in the context of electrode design.

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....

Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

Science.gov (United States)

Lo, Momath; Diaw, Abdou K D; Gningue-Sall, Diariatou; Aaron, Jean-Jacques; Oturan, Mehmet A; Chehimi, Mohamed M

2018-05-09

Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb 2+ , Cu 2+ , and Cd 2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu 2+ , Cd 2+ , and Pb 2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99 nM for Cu 2+ , Cd 2+ , and Pb 2+ , respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

Carbon Powder Based Films on Traditional Solid Electrodes as an Alternative to Disposable Electrodes

Czech Academy of Sciences Publication Activity Database

Josypčuk, Bohdan; Barek, J.; Fojta, Miroslav

2006-01-01

Roč. 18, č. 11 (2006), s. 1126-1130 ISSN 1040-0397 R&D Projects: GA MPO 1H-PK/42; GA ČR GA203/03/0182; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z50040507 Keywords : voltammetry * solid electrodes * ink film * disposable sensor Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.444, year: 2006

Effects of the top-electrode preparation method on the ferroelectric properties of Pt/Pb(Zr,Ti)O3/Pt thin film capacitors

International Nuclear Information System (INIS)

Lee, Eun Gu; Lee, Jae Gab; Kim, Sun Jae

2006-01-01

The deformation in the hysteresis loop of Pt/PZT/Pt thin-film capacitors due to deposition and patterning of the top electrode has been investigated. The PZT film was aged during the deposition of the top electrode and was positively poled during reactive ion etching (RIE). The PZT film having sputtered top electrode was very sensitive to the RIE process. The film with a thinner top electrode showed less initial switching polarization due to less compressive stress, but better fatigue characteristics due to an enhanced partial-switching region.

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)

Tyszczuk, Katarzyna

2011-01-01

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.

Transferred metal electrode films for large-area electronic devices

International Nuclear Information System (INIS)

Yang, Jin-Guo; Kam, Fong-Yu; Chua, Lay-Lay

2014-01-01

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 −1 have been obtained for 50-nm thin films of polystyrene and a cyclic olefin copolymer TOPAS ® (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

Nanostructured manganese oxide thin films as electrode material for supercapacitors

Science.gov (United States)

Xia, Hui; Lai, Man On; Lu, Li

2011-01-01

Electrochemical capacitors, also called supercapacitors, are alternative energy storage devices, particularly for applications requiring high power densities. Recently, manganese oxides have been extensively evaluated as electrode materials for supercapacitors due to their low cost, environmental benignity, and promising supercapacitive performance. In order to maximize the utilization of manganese oxides as the electrode material for the supercapacitors and improve their supercapacitive performance, the nanostructured manganese oxides have therefore been developed. This paper reviews the synthesis of the nanostructured manganese oxide thin films by different methods and the supercapacitive performance of different nanostructures.

Electrode size and boundary condition independent measurement of the effective piezoelectric coefficient of thin films

Directory of Open Access Journals (Sweden)

M. Stewart

2015-02-01

Full Text Available The determination of the piezoelectric coefficient of thin films using interferometry is hindered by bending contributions. Using finite element analysis (FEA simulations, we show that the Lefki and Dormans approximations using either single or double-beam measurements cannot be used with finite top electrode sizes. We introduce a novel method for characterising piezoelectric thin films which uses a differential measurement over the discontinuity at the electrode edge as an internal reference, thereby eliminating bending contributions. This step height is shown to be electrode size and boundary condition independent. An analytical expression is derived which gives good agreement with FEA predictions of the step height.

Preferential growth and enhanced dielectric properties of Ba0.7Sr0.3TiO3 thin films with preannealed Pt bottom electrode

International Nuclear Information System (INIS)

Zhu Xiaohong; Ren Yinjuan; Zhang Caiyun; Zhu Jiliang; Zhu Jianguo; Xiao Dingquan; Defaÿ, Emmanuel; Aïd, Marc

2013-01-01

Ba 0.7 Sr 0.3 TiO 3 (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)

Preferential growth and enhanced dielectric properties of Ba0.7Sr0.3TiO3 thin films with preannealed Pt bottom electrode

Science.gov (United States)

Zhu, Xiaohong; Defaÿ, Emmanuel; Aïd, Marc; Ren, Yinjuan; Zhang, Caiyun; Zhu, Jiliang; Zhu, Jianguo; Xiao, Dingquan

2013-03-01

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.

High-Quality AZO/Au/AZO Sandwich Film with Ultralow Optical Loss and Resistivity for Transparent Flexible Electrodes.

Science.gov (United States)

Zhou, Hua; Xie, Jing; Mai, Manfang; Wang, Jing; Shen, Xiangqian; Wang, Shuying; Zhang, Lihua; Kisslinger, Kim; Wang, Hui-Qiong; Zhang, Jinxing; Li, Yu; Deng, Junhong; Ke, Shanming; Zeng, Xierong

2018-05-09

Transparent flexible electrodes are in ever-growing demand for modern stretchable optoelectronic devices, such as display technologies, solar cells, and smart windows. Such sandwich-film-electrodes deposited on polymer substrates are unattainable because of the low quality of the films, inducing a relatively large optical loss and resistivity as well as a difficulty in elucidating the interference behavior of light. In this article, we report a high-quality AZO/Au/AZO sandwich film with excellent optoelectronic performance, e.g., an average transmittance of about 81.7% (including the substrate contribution) over the visible range, a sheet resistance of 5 Ω/sq, and a figure-of-merit (FoM) factor of ∼55.1. These values are well ahead of those previously reported for sandwich-film-electrodes. Additionally, the interference behaviors of light modulated by the coat and metal layers have been explored with the employment of transmittance spectra and numerical simulations. In particular, a heater device based on an AZO/Au/AZO sandwich film exhibits high performance such as short response time (∼5 s) and uniform temperature field. This work provides a deep insight into the improvement of the film quality of the sandwich electrodes and the design of high-performance transparent flexible devices by the application of a flexible substrate with an atomically smooth surface.

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

International Nuclear Information System (INIS)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-01-01

Highlights: ► Surface-textured AZO films were achieved by combining PDMS method with wet etching. ► The AZO film deposited at 230 °C by PDMS exhibited the best performance. ► It is due to the higher plasma density supplied from PDMS system. ► Wet etching of the films produces a crater-like rough surface morphology. - Abstract: A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 °C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 × 10 −4 Ω cm with the carrier concentration of 1.65 × 10 21 cm −3 and Hall mobility of 11.3 cm 2 /V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Plasma assisted fabrication of multi-layer graphene/nickel hybrid film as enhanced micro-supercapacitor electrodes

Science.gov (United States)

Ding, Q.; Li, W. L.; Zhao, W. L.; Wang, J. Y.; Xing, Y. P.; Li, X.; Xue, T.; Qi, W.; Zhang, K. L.; Yang, Z. C.; Zhao, J. S.

2017-03-01

A facile synthesis strategy has been developed for fabricating multi-layer graphene/nickel hybrid film as micro-supercapacitor electrodes by using plasma enhanced chemical vapor deposition. The as-presented method is advantageous for rapid graphene growth at relatively low temperature of 650 °C. In addition, after pre-treating for the as-deposited nickel film by using argon plasma bombardment, the surface-to-volume ratio of graphene film on the treated nickel substrate is effectively increased by the increasing of surface roughness. This is demonstrated by the characterization results from transmission electron microscopy, scanning electron microscope and atomic force microscopy. Moreover, the electrochemical performance of the resultant graphene/nickel hybrid film as micro-supercapacitor working electrode was investigated by cyclic voltammetry and galvanostatic charge/discharge measurements. It was found that the increase of the surface-to-volume ratio of graphene/nickel hybrid film improved the specific capacitance of 10 times as the working electrode of micro-supercapacitor. Finally, by using comb columnar shadow mask pattern, the micro-supercapacitor full cell device was fabricated. The electrochemical performance measurements of the micro-supercapacitor devices indicate that the method presented in this study provides an effective way to fabricate micro-supercapacitor device with enhanced energy storage property.

Mechanical measurements on lithium phosphorous oxynitride coated silicon thin film electrodes for lithium-ion batteries during lithiation and delithiation

Energy Technology Data Exchange (ETDEWEB)

Al-Obeidi, Ahmed, E-mail: alobeidi@mit.edu; Thompson, Carl V., E-mail: reiner.moenig@kit.edu, E-mail: cthomp@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Kramer, Dominik, E-mail: dominik.kramer@kit.edu; Mönig, Reiner, E-mail: reiner.moenig@kit.edu, E-mail: cthomp@mit.edu [Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Helmholtzstraße 11, 89081 Ulm (Germany); Boles, Steven T., E-mail: steven.t.boles@polyu.edu.hk [Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Hong Kong Polytechnic University, 11 Yuk Choi Rd, Hung Hom (Hong Kong)

2016-08-15

The development of large stresses during lithiation and delithiation drives mechanical and chemical degradation processes (cracking and electrolyte decomposition) in thin film silicon anodes that complicate the study of normal electrochemical and mechanical processes. To reduce these effects, lithium phosphorous oxynitride (LiPON) coatings were applied to silicon thin film electrodes. Applying a LiPON coating has two purposes. First, the coating acts as a stable artificial solid electrolyte interphase. Second, it limits mechanical degradation by retaining the electrode's planar morphology during cycling. The development of stress in LiPON-coated electrodes was monitored using substrate curvature measurements. LiPON-coated electrodes displayed highly reproducible cycle-to-cycle behavior, unlike uncoated electrodes which had poorer coulombic efficiency and exhibited a continual loss in stress magnitude with continued cycling due to film fracture. The improved mechanical stability of the coated silicon electrodes allowed for a better investigation of rate effects and variations of mechanical properties during electrochemical cycling.

Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes

International Nuclear Information System (INIS)

Holm, Allan Hjarbaek; Vase, Karina Hojrup; Winther-Jensen, Bjorn; Pedersen, Steen Uttrup; Daasbjerg, Kim

2007-01-01

The hydroquinone/quinone (H 2 Q/Q) redox system was tethered to glassy carbon surfaces using first an electrochemical pre-oxidation treatment to afford carboxylic acid functionalities followed by immobilizing the H 2 Q precursor, n-(2,5-dimethoxyphenyl)alkan-1-amine (general structure: H 2 N-(CH 2 ) n -C 6 H 3 (OCH 3 ) 2 , n = 1, 2, 4, 8, and 12), by carbodiimide chemistry and a final demethylation reaction. The resultant surfaces exhibited the expected chemical reversibility in aqueous solution with a pH-sensitive position of the formal potential (∼55 mV/pH unit), and an increase in the peak potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics was faster than expected for longer alkyl spacers. We suggest that film disorder, electrode-mediating effects, and a roughened electrode material could account for these apparent inconsistencies. To further understand such effects, two complementary electrode modification strategies leading to better film ordering on carbon were adapted; immobilizing a thin layer of benzoic acid by oxidative deposition of 4-aminobenzoic acid or employing a plasma deposition process to tether an acid analogue. Analysis of the various electrodes was accomplished by electrochemical methods, atomic force microscopy, and X-ray photoelectron spectroscopy

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.

Highly Conductive PEDOT:PSS Films with 1,3-Dimethyl-2-Imidazolidinone as Transparent Electrodes for Organic Light-Emitting Diodes.

Science.gov (United States)

Kim, Jin Hee; Joo, Chul Woong; Lee, Jonghee; Seo, Yoon Kyung; Han, Joo Won; Oh, Ji Yoon; Kim, Jong Su; Yu, Seunggun; Lee, Jae Hyun; Lee, Jeong-Ik; Yun, Changhun; Choi, Bum Ho; Kim, Yong Hyun

2016-09-01

Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) films as transparent electrodes for organic light-emitting diodes (OLEDs) are doped with a new solvent 1,3-dimethyl-2-imidazolidinone (DMI) and are optimized using solvent post-treatment. The DMI doped PSS films show significantly enhanced conductivities up to 812.1 S cm(-1) . The sheet resistance of the PSS films doped with DMI is further reduced by various solvent post-treatment. The effect of solvent post-treatment on DMI doped PSS films is investigated and is shown to reduce insulating PSS in the conductive films. The solvent posttreated PSS films are successfully employed as transparent electrodes in white OLEDs. It is shown that the efficiency of OLEDs with the optimized DMI doped PSS films is higher than that of reference OLEDs doped with a conventional solvent (ethylene glycol). The results present that the optimized PSS films with the new solvent of DMI can be a promising transparent electrode for low-cost, efficient ITO-free white OLEDs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Layer-by-layer assembled polyaniline nanofiber/multiwall carbon nanotube thin film electrodes for high-power and high-energy storage applications.

Science.gov (United States)

Hyder, Md Nasim; Lee, Seung Woo; Cebeci, Fevzi Ç; Schmidt, Daniel J; Shao-Horn, Yang; Hammond, Paula T

2011-11-22

Thin film electrodes of polyaniline (PANi) nanofibers and functionalized multiwall carbon nanotubes (MWNTs) are created by layer-by-layer (LbL) assembly for microbatteries or -electrochemical capacitors. Highly stable cationic PANi nanofibers, synthesized from the rapid aqueous phase polymerization of aniline, are assembled with carboxylic acid functionalized MWNT into LbL films. The pH-dependent surface charge of PANi nanofibers and MWNTs allows the system to behave like weak polyelectrolytes with controllable LbL film thickness and morphology by varying the number of bilayers. The LbL-PANi/MWNT films consist of a nanoscale interpenetrating network structure with well developed nanopores that yield excellent electrochemical performance for energy storage applications. These LbL-PANi/MWNT films in lithium cell can store high volumetric capacitance (~238 ± 32 F/cm(3)) and high volumetric capacity (~210 mAh/cm(3)). In addition, rate-dependent galvanostatic tests show LbL-PANi/MWNT films can deliver both high power and high energy density (~220 Wh/L(electrode) at ~100 kW/L(electrode)) and could be promising positive electrode materials for thin film microbatteries or electrochemical capacitors. © 2011 American Chemical Society

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju [Information and Electronic Materials Research Laboratory, Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Son, Myoungwoo [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Ham, Moon-Ho [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Lee, Woong [School of Nano and Advanced Materials Engineering, Changwon National University, 9 Sarim-Dong, Changwon, Gyeongnam 641-773 (Korea, Republic of); Myoung, Jae-Min, E-mail: jmmyoung@yonsei.ac.kr [Information and Electronic Materials Research Laboratory, Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Surface-textured AZO films were achieved by combining PDMS method with wet etching. Black-Right-Pointing-Pointer The AZO film deposited at 230 Degree-Sign C by PDMS exhibited the best performance. Black-Right-Pointing-Pointer It is due to the higher plasma density supplied from PDMS system. Black-Right-Pointing-Pointer Wet etching of the films produces a crater-like rough surface morphology. - Abstract: A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 Degree-Sign C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 Multiplication-Sign 10{sup -4} {Omega} cm with the carrier concentration of 1.65 Multiplication-Sign 10{sup 21} cm{sup -3} and Hall mobility of 11.3 cm{sup 2}/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

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

International Nuclear Information System (INIS)

Choi, J.H.; Kang, S.H.; Oh, H.S.; Yu, T.H.; Sohn, I.S.

2013-01-01

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

Bilayered Oxide thin films for transparent electrode application

Science.gov (United States)

Dutta, Titas; Narayan, Jagdish

2008-10-01

Ga doped ZnO films with electrical and optical properties comparable to indium tin oxide (ITO) is a promising candidate for transparent conducting oxides (TCOs) because of its superior stability in hydrogen environment, benign nature and relatively inexpensive supply. However, ZnO based TCO films suffer from low work function, which is a critical parameter for device applications. We report here the growth of a novel bilayered structure consisting of very thin (few monolayers) ITO, MoOx layer on Zn0.95Ga0.05O film for transparent electrode applications by using pulsed laser deposition technique at different temperatures and oxygen partial pressure. The characteristics of the ITO film and the heterostructure have been investigated in detail using XRD, TEM, XPS, and electrical and optical property measurements. It is envisaged that the overall transmittance and the resistivity are dictated by the thicker layer of ZnGa0.05O beneath the ITO layer. Hence, this study is aimed to improve the surface characteristics without affecting the overall transmittance and sheet resistance. This will enhance the transport of the carriers across the heterojunction in the device, thus, resulting in the increase in device efficiency.

On dual nature of effect of adsorbed polymeric hydroxide films on rate of different electrode processes

International Nuclear Information System (INIS)

Zakharkina, P.S.; Korshunov, V.N.

1985-01-01

The effect of cation Er 3+ hydrolysis products on the electrochemical behaviour of Zn and Na amalgams is studied. The i, t-curves are presented which are moasUred from a film Hg-electrode in 1M LiCl- and 1MNaCl solUtions both with and without the 10 -3 MErCl 3 addition, along with the I, t-dependences obtained from a rotation disk Zn-electrode at E=-1.45 B against the background of 0.1 MLi 2 SO 4 with the 1.5x10 -3 M Er 2 (SO 4 ) 3 addition. Polymeric films of REE oxohydroxo compounds exhibit a distinct dualism in the effect on the rate of different electrode reactions; provided a proton donor is the depolarizator, the films being considered confirm their name of catalytically active matrices accelerating hydrogen evolution by a modified bridge mechanism variant. In case of metal charge-ionization process these films become inhibitors and the more effective, the more hydrated is the corresponding REE ion

Magnetron sputtered TiN thin films toward enhanced performance supercapacitor electrodes

KAUST Repository

Wei, Binbin

2018-04-09

Supercapacitors as a new type of energy storage devices bridging the gap between conventional capacitors and batteries have aroused widespread concern. Herein, binder-free titanium nitride (TiN) thin film electrodes for supercapacitors prepared by reactive magnetron sputtering technology are reported. The effect of N2 content on the supercapacitor performance is evaluated. A highest specific capacitance of 27.3 mF cm−2 at a current density of 1.0 mA cm−2, together with excellent cycling performance (98.2% capacitance retention after 20,000 cycles at 2.0 mA cm−2) is achieved in a 0.5 M H2SO4 aqueous electrolyte. More importantly, a symmetric supercapacitor device assembled on the basis of TiN thin films can deliver a maximum energy density of 17.6 mWh cm−3 at a current density of 0.2 mA cm−2 and a maximum power density of 10.8 W cm−3 at a current density of 2 mA cm−2 with remarkable cycling stability. As a consequence, TiN thin films demonstrate great potential as promising supercapacitor electrode materials.

Magnetron sputtered TiN thin films toward enhanced performance supercapacitor electrodes

KAUST Repository

Wei, Binbin; Liang, Hanfeng; Zhang, Dongfang; Qi, Zhengbing; Shen, Hao; Wang, Zhoucheng

2018-01-01

Supercapacitors as a new type of energy storage devices bridging the gap between conventional capacitors and batteries have aroused widespread concern. Herein, binder-free titanium nitride (TiN) thin film electrodes for supercapacitors prepared by reactive magnetron sputtering technology are reported. The effect of N2 content on the supercapacitor performance is evaluated. A highest specific capacitance of 27.3 mF cm−2 at a current density of 1.0 mA cm−2, together with excellent cycling performance (98.2% capacitance retention after 20,000 cycles at 2.0 mA cm−2) is achieved in a 0.5 M H2SO4 aqueous electrolyte. More importantly, a symmetric supercapacitor device assembled on the basis of TiN thin films can deliver a maximum energy density of 17.6 mWh cm−3 at a current density of 0.2 mA cm−2 and a maximum power density of 10.8 W cm−3 at a current density of 2 mA cm−2 with remarkable cycling stability. As a consequence, TiN thin films demonstrate great potential as promising supercapacitor electrode materials.

Electrical properties of graphene film for counter electrode in dye sensitized solar cells

Science.gov (United States)

Khalifa, Ali; Shafie, S.; Hasan, W. Z. W.; Lim, H. N.; Rusop, M.; Samaila, Buda

2018-05-01

A graphene counter electrode for dye-sensitized solar cell was prepared simply by drop casting method on a conducting FTO glass at room temperature. Raman spectroscopy was used to study the defection in the graphene films. The sheet resistance was also measured and recoded minimum value of 7.04 Ω/□ at 22.19µm thickness. The casted films show good adhesion to substrates with low defects. A DSSC based on graphene counter electrode demonstrates reasonable conversion efficiency of 2.78% with short circuit current of 7.60mA, open circuit voltage of 0.69V and fill factor of 0.52. The high conductivity and low defects render the prepared graphene dispersion for DSSCs' CE application.

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

Hydrogen-bonding effects on film structure and photoelectrochemical properties of porphyrin and fullerene composites on nanostructured TiO 2 electrodes

NARCIS (Netherlands)

Kira, Aiko; Tanaka, Masanobu; Umeyama, Tomokazu; Matano, Yoshihiro; Yoshimoto, Naoki; Zhang, Yi; Ye, Shen; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

2007-01-01

Hydrogen-bonding effects on film structures and photophysical, photoelectrochemical, and photovoltaic properties have been examined in mixed films of porphyrin and fullerene composites with and without hydrogen bonding on nanostructured TiO2 electrodes. The nanostructured TiO2 electrodes modified

Enzymatic logic calculation systems based on solid-state electrochemiluminescence and molecularly imprinted polymer film electrodes.

Science.gov (United States)

Lian, Wenjing; Liang, Jiying; Shen, Li; Jin, Yue; Liu, Hongyun

2018-02-15

The molecularly imprinted polymer (MIP) films were electropolymerized on the surface of Au electrodes with luminol and pyrrole (PY) as the two monomers and ampicillin (AM) as the template molecule. The electrochemiluminescence (ECL) intensity peak of polyluminol (PL) of the AM-free MIP films at 0.7V vs Ag/AgCl could be greatly enhanced by AM rebinding. In addition, the ECL signals of the MIP films could also be enhanced by the addition of glucose oxidase (GOD)/glucose and/or ferrocenedicarboxylic acid (Fc(COOH) 2 ) in the testing solution. Moreover, Fc(COOH) 2 exhibited cyclic voltammetric (CV) response at the AM-free MIP film electrodes. Based on these results, a binary 3-input/6-output biomolecular logic gate system was established with AM, GOD and Fc(COOH) 2 as inputs and the ECL responses at different levels and CV signal as outputs. Some functional non-Boolean logic devices such as an encoder, a decoder and a demultiplexer were also constructed on the same platform. Particularly, on the basis of the same system, a ternary AND logic gate was established. The present work combined MIP film electrodes, the solid-state ECL, and the enzymatic reaction together, and various types of biomolecular logic circuits and devices were developed, which opened a novel avenue to construct more complicated bio-logic gate systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Oleic acid-assisted exfoliated few layer graphene films as counter electrode in dye-sensitized solar cell

International Nuclear Information System (INIS)

Liu, Jincheng; Wang, Yinjie; Sun, Darren Delai

2012-01-01

Highlights: ► Few layer graphene was obtained by liquid exfoliation in oleic acid (OLA). ► The concentration of exfoliated few layer graphene is as high as 1.3 mg/mL. ► OLA-assisted graphite (OLA-G) film has high catalytic activity. ► A power conversion efficiency of 3.56% can be gained by DSSCs with the counter electrode of OLA-G film. - Abstract: We have demonstrated a facile sonication method to exfoliate graphite into few layer graphene with a high concentration of 1.3 mg/mL in oleic acid (OLA). The exfoliations of natural graphite in oleylamine (OA) and trioctylphosphine (TOP) are investigated as a comparison. The few layer graphene dispersion in OLA and the graphite nanoparticles in OA are confirmed by transmission electron microscopy (TEM) observation. The exfoliated graphene dispersion in OLA (OLA-G) and graphite dispersion in OA (OA-G) are fabricated into a film on the FTO substrate by the doctor-blading method. The morphology and catalytic activity in the redox couple regeneration of all the graphite films are examined by field emission scanning electron microscopy and cyclic voltammograms. The OLA-G films on FTO glass with few layer graphene flakes shows better catalytic activity than the OA-G films. The energy conversion efficiency of the cell with the OLA-G film as counter electrode reached 3.56%, which is 70% of dye-sensitized solar cell (DSSC) with the sputtering-Pt counter electrode under the same experimental condition.

High conductivity and transparent aluminum-based multi-layer source/drain electrodes for thin film transistors

Science.gov (United States)

Yao, Rihui; Zhang, Hongke; Fang, Zhiqiang; Ning, Honglong; Zheng, Zeke; Li, Xiaoqing; Zhang, Xiaochen; Cai, Wei; Lu, Xubing; Peng, Junbiao

2018-02-01

In this study, high conductivity and transparent multi-layer (AZO/Al/AZO-/Al/AZO) source/drain (S/D) electrodes for thin film transistors were fabricated via conventional physical vapor deposition approaches, without toxic elements or further thermal annealing process. The 68 nm-thick multi-layer films with excellent optical properties (transparency: 82.64%), good electrical properties (resistivity: 6.64  ×  10-5 Ω m, work function: 3.95 eV), and superior surface roughness (R q   =  0.757 nm with scanning area of 5  ×  5 µm2) were fabricated as the S/D electrodes. Significantly, comprehensive performances of AZO films are enhanced by the insertion of ultra-thin Al layers. The optimal transparent TFT with this multi-layer S/D electrodes exhibited a decent electrical performance with a saturation mobility (µ sat) of 3.2 cm2 V-1 s-1, an I on/I off ratio of 1.59  ×  106, a subthreshold swing of 1.05 V/decade. The contact resistance of AZO/Al/AZO/Al/AZO multi-layer electrodes is as low as 0.29 MΩ. Moreover, the average visible light transmittance of the unpatterned multi-layers constituting a whole transparent TFT could reach 72.5%. The high conductivity and transparent multi-layer S/D electrodes for transparent TFTs possessed great potential for the applications of the green and transparent displays industry.

Preparation and characterization of graphene/turbostratic carbon derived from chitosan film for supercapacitor electrodes

Science.gov (United States)

Hanappi, M. F. Y. M.; Deraman, M.; Suleman, M.; Othman, M. A. R.; Basri, N. H.; Nor, N. S. M.; Hamdan, E.; Sazali, N. E. S.; Tajuddin, N. S. M.

2018-04-01

Electrochemical capacitors or supercapacitors are the potential energy storage devices which are known for having higher specific capacitance and specific energy than electrolytic capacitors. Electric double-layer capacitors (EDLCs) also referred as ultracapacitors is a class of supercapacitors that employ different forms of carbon like activated carbon, CNT, graphene etc., as electrodes. The performance of the supercapacitors is determined by its components namely electrolyte, electrode, etc. Carbon electrodes with high surface area and desired pore size distribution are always preferred and which can be tailored by varying the precursor and method of preparation. In recent years, owing to their low cost, ease of synthesis, high stability and conductivity, the activated carbons derived from biomass precursors have been investigated as potential electrode material for the EDLCs. In this report, we present the preparation and characterization of graphene/turbostratic carbon monolith (CM) electrodes from the carbon grains (CGs) obtained by carbonization (under the flow of nitrogen, N2 gas and over a temperature range from 600 °C to 1000 °C) of biomass precursor chitosan film. The procedure to prepare the chitosan film is described elsewhere. The carbon grains are characterized using Raman spectroscopy (RS) and X-ray diffraction (XRD). We expect that the CGs would have the similar characteristics as graphene and would be a potential electrode material for EDLCs application.

Improvement in fatigue property for a PZT ferroelectric film device with SRO electrode film prepared by chemical solution deposition

International Nuclear Information System (INIS)

Miyazaki, H.; Miwa, Y.; Suzuki, H.

2007-01-01

PZT films with (1 0 0) and (1 1 0) orientation were prepared by spin coating using the chemical solution deposition (CSD) method on an SRO/Si or a Pt/Ti/SiO 2 /Si substrate. The remnant polarization and the saturation polarization of the PZT/SRO/Si film were 21 and 35 μC/cm 2 , and those of the PZT/Pt/Ti/SiO 2 /Si film were 20 and 31 μC/cm 2 . The remnant polarization of the PZT/SRO/Si film maintained more than 10 8 switching cycles, and the fatigue property was observed for the PZT film fabricated on the Pt/Ti/SiO 2 /Si electrode

Critical electrode size in measurement of d33 coefficient of films via spatial distribution of piezoelectric displacement

International Nuclear Information System (INIS)

Wang Zhihong; Miao Jianmin

2008-01-01

Spatial distributions of piezoelectric displacement response across the top electrode have been used in this paper to measure the piezoelectric coefficient d 33 of films based on the converse piezoelectric effect. The technical details and features of a scanning laser Doppler vibrometer have been summarized and discussed for accurately obtaining the spatial displacement distributions. Three definitions, including the apparent, the effective and the constrained piezoelectric coefficient d 33 of films, have been clarified and used to better understand the fundamental phenomenon behind the measured displacement distributions. Finite element analysis reveals that both the apparent and the effective piezoelectric coefficients depend on the electrode radius of test capacitor as well as film thickness. However, there exists a critical electrode size for apparent piezoelectric coefficients and a critical test capacitor aspect ratio for effective piezoelectric coefficient. Beyond their respective critical values, both coefficients converge to the constrained piezoelectric coefficient irrespective of film thickness. The finding of the critical electric size makes it possible to consistently measure the constrained piezoelectric coefficient of films by using the spatial distributions of the piezoelectric displacement response and becomes the fundamental criterion of this measurement method

Pt/AlPO{sub 4} nanocomposite thin-film electrodes for ethanol electrooxidation

Energy Technology Data Exchange (ETDEWEB)

Oh, Yuhong; Kang, Joonhyeon; Nam, Seunghoon; Byun, Sujin [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Byungwoo, E-mail: byungwoo@snu.ac.kr [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)

2012-07-16

The enhanced catalytic properties toward ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposite thin-film electrodes were investigated. The Pt/AlPO{sub 4} nanocomposites with various Al/Pt ratios (0.27, 0.57, and 0.96) were fabricated by a co-sputtering method. All of the Pt/AlPO{sub 4} nanocomposites showed a negative shift in the onset potential and a higher current density than those of pure Pt electrode for the electrooxidation of ethanol. Among the various Pt/AlPO{sub 4} nanocomposite thin-film electrodes, the electrode with an atomic ratio of Al to Pt of 0.57 showed the highest electrocatalytic activity for ethanol electrooxidation. The activation enthalpy for the optimum Pt/AlPO{sub 4} nanocomposite was approximately 0.05 eV lower than that of pure Pt. It is believed that the enhancement in catalytic activity is due to the electron-rich Pt resulting from the Fermi-energy difference between Pt and AlPO{sub 4}. - Highlights: Black-Right-Pointing-Pointer The enhanced ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposites is investigated. Black-Right-Pointing-Pointer The Pt/AlPO{sub 4} exhibits higher current density and lower onset potential than pure Pt. Black-Right-Pointing-Pointer The activation enthalpy for optimum Pt/AlPO{sub 4} electrode is {approx}0.05 eV lower than pure Pt. Black-Right-Pointing-Pointer XPS shows electron-rich Pt due to Fermi-energy difference between Pt and AlPO{sub 4}.

Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

International Nuclear Information System (INIS)

Panky, Sreedevi; Thandavan, Kavitha; Sivalingam, Durgajanani; Sethuraman, Swaminathan; Krishnan, Uma Maheswari; Jeyaprakash, Beri Gopalakrishnan; Rayappan, John Bosco Balaguru

2013-01-01

Nanostructured cerium oxide (CeO 2 ) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO 3 ) 3 ·6H 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 2 and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO 2 /TCO film to form the lipase/nano-CeO 2 /TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO 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 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 CeO 2 /TCO film and hence the lipase/nano-CeO 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 μM with sharp response time of 5 s and a shelf life of about 6

In vitro biocompatibility and electrical stability of thick-film platinum/gold alloy electrodes printed on alumina

Science.gov (United States)

Carnicer-Lombarte, Alejandro; Lancashire, Henry T.; Vanhoestenberghe, Anne

2017-06-01

Objective. High-density electrode arrays are a powerful tool in both clinical neuroscience and basic research. However, current manufacturing techniques require the use of specialised techniques and equipment, which are available to few labs. We have developed a high-density electrode array with customisable design, manufactured using simple printing techniques and with commercially available materials. Approach. Electrode arrays were manufactured by thick-film printing a platinum-gold alloy (Pt/Au) and an insulating dielectric on 96% alumina ceramic plates. Arrays were conditioned in serum and serum-free conditions, with and without 1 kHz, 200 µA, charge balanced stimulation for up to 21 d. Array biocompatibility was assessed using an extract assay and a PC-12 cell contact assay. Electrode impedance, charge storage capacity and charge injection capacity were before and after array conditioning. Main results. The manufactured Pt/Au electrodes have a highly porous surface and exhibit electrical properties comparable to arrays manufactured using alternative techniques. Materials used in array manufacture were found to be non-toxic to L929 fibroblasts by extract assay, and neuronal-like PC-12 cells adhered and extended neurites on the array surfaces. Arrays remained functional after long-term delivery of electrical pulses while exposed to protein-rich environments. Charge storage capacities and charge injection capacities increased following stimulation accounted for by an increase in surface index (real surface area) observed by vertical scanning interferometry. Further, we observed accumulation of proteins at the electrode sites following conditioning in the presence of serum. Significance. This study demonstrates the in vitro biocompatibility of commercially available thick-film printing materials. The printing technique is both simple and versatile, with layouts readily modified to produce customized electrode arrays. Thick-film electrode arrays are an

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

International Nuclear Information System (INIS)

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

2016-01-01

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 Aa), and low electrical resistivity (4.2 x 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 x 10 7 , 0.43 V/decade, 0.7 V, and 2.1 cm 2 /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. (orig.)

Preparation of TiO2/boron-doped diamond/Ta multilayer films and use as electrode materials for supercapacitors

Science.gov (United States)

Shi, Chao; Li, Hongji; Li, Cuiping; Li, Mingji; Qu, Changqing; Yang, Baohe

2015-12-01

We report nanostructured TiO2/boron-doped diamond (BDD)/Ta multilayer films and their electrochemical performances as supercapacitor electrodes. The BDD films were grown on Ta substrates using electron-assisted hot filament chemical vapor deposition. Ti metal layers were deposited on the BDD surfaces by radio frequency magnetron sputtering, and nanostructured TiO2/BDD/Ta thin films were prepared by electrochemical etching and thermal annealing. The successful formation of TiO2 and Ta layered nanostructures was demonstrated using scanning electron and transmission electron microscopies. The electrochemical responses of these electrodes were evaluated by examining their use as electrical double-layer capacitors, using cyclic voltammetry, and galvanostatic charge/discharge and impedance measurements. When the TiO2/BDD/Ta film was used as the working electrode with 0.1 M Na2SO4 as the electrolyte, the capacitor had a specific capacitance of 5.23 mF cm-2 at a scan rate of 5 mV s-1 for a B/C ratio of 0.1% w/w. Furthermore, the TiO2/BDD/Ta film had improved electrochemical stability, with a retention of 89.3% after 500 cycles. This electrochemical behavior is attributed to the quality of the BDD, the surface roughness and electrocatalytic activities of the TiO2 layer and Ta nanoporous structures, and the synergies between them. These results show that TiO2/BDD/Ta films are promising as capacitor electrodes for special applications.

Functionalization of indium-tin-oxide electrodes by laser-nanostructured gold thin films for biosensing applications

Energy Technology Data Exchange (ETDEWEB)

Grochowska, Katarzyna, E-mail: kgrochowska@imp.gda.pl [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland); Siuzdak, Katarzyna [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland); Karczewski, Jakub [Solid State Physics Department, Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, 11/12 Narutowicza St, 80-233, Gdańsk (Poland); Śliwiński, Gerard [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland)

2015-12-01

Graphical abstract: - Highlights: • ITO electrodes modified by NP arrays prepared by laser dewetting of thin Au films. • Enhanced activity, linear response and high sensitivity towards glucose. • Promising biosensor material AuNP-modified ITO of improved performance. - Abstract: 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.

Enhanced selectivity of boron doped diamond electrodes for the detection of dopamine and ascorbic acid by increasing the film thickness

Energy Technology Data Exchange (ETDEWEB)

Qi, Yao; Long, Hangyu [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Ma, Li, E-mail: marycsupm@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Wei, Quiping, E-mail: qiupwei@csu.edu.cn [School of Material Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Li, Site [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Yu, Zhiming [School of Material Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Hu, Jingyuan [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Peizhi [Key laboratory of interface science and engineering in advanced materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024,PR China (China); Wang, Yijia [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Meng, Lingcong [Department of Chemistry, University of Warwick, Coventry, West Midlands CV4 7AL (United Kingdom)

2016-12-30

Highlights: • BDD electrodes with different thickness have been fabricated. • BDD electrodes are used for simultaneous detection of DA and AA. • Anodic pretreatment enhance the separation of DA and AA oxidation peak potential. • Thicker BDD electrode show better performance for DA detection coexisting with AA. - Abstract: In this paper, boron doped diamond (BDD) with different thickness were prepared by hot filament chemical vapor deposition. The performance of BDD electrodes for detecting dopamine (DA) and ascorbic acid (AA) were investigated. Scanning electron microscopy and Raman spectra reveal the grain size increases and the film quality improves with the increase of film thickness. Electrochemical test show that the transfer coefficient in [Fe{sub 3} (CN) {sub 6}]{sup 3−/4−} redox system increases with the increase of the film thickness. The results of selectivity and sensitivity for DA mixed with AA detection show that 8h-BDD and 12h-BDD electrodes possess well selective separated oxidation peaks of DA and AA, and the 12h-BDD electrode exhibits optimal sensitivity until the DA concentration drops to 1 μ M.

In situ photoelectrochemistry and Raman spectroscopic characterization on the surface oxide film of nickel electrode in 30 wt.% KOH solution

International Nuclear Information System (INIS)

Nan Junmin; Yang Yong; Lin Zugeng

2006-01-01

The oxide films of nickel electrode formed in 30 wt.% KOH solution under potentiodynamic conditions were characterized by means of electrochemical, in situ PhotoElectrochemistry Measurement (PEM) and Confocal Microprobe Raman spectroscopic techniques. The results showed that a composite oxide film was produced on nickel electrode, in which aroused cathodic or anodic photocurrent depending upon polarization potentials. The cathodic photocurrent at -0.8 V was raised from the amorphous film containing nickel hydroxide and nickel monoxide, and mainly attributed to the formation of NiO through the separation of the cavity and electron when laser light irradiates nickel electrode. With the potential increasing to more positive values, Ni 3 O 4 and high-valence nickel oxides with the structure of NiO 2 were formed successively. The composite film formed in positive potential aroused anodic photocurrent from 0.33 V. The anodic photocurrent was attributed the formation of oxygen through the cavity reaction with hydroxyl on solution interface. In addition, it is demonstrated that the reduction resultants of high-valence nickel oxides were amorphous, and the oxide film could not be reduced completely. A stable oxide film could be gradually formed on the surface of nickel electrode with the cycling and aging in 30 wt.% KOH solution

Patterning of metallic electrodes on flexible substrates for organic thin-film transistors using a laser thermal printing method

International Nuclear Information System (INIS)

Chen, Kun-Tso; Lin, Yu-Hsuan; Ho, Jeng-Rong; Chen, Chih-Kant; Liu, Sung-Ho; Liao, Jin-Long; Cheng, Hua-Chi

2011-01-01

We report on a laser thermal printing method for transferring patterned metallic thin films on flexible plastic substrates using a pulsed CO 2 laser. Aluminium and silver line patterns, with micrometre scale resolution on poly(ethylene terephthalate) substrates, are shown. The printed electrodes demonstrate good conductivity and fulfil the properties for bottom-contact organic thin-film transistors. In addition to providing the energy for transferring the film, the absorption of laser light results in a rise in the temperature of the film and the substrate. This also further anneals the film and softens the plastic substrate. Consequently, it is possible to obtain a film with better surface morphology and with its film thickness implanted in part into the plastic surface. This implantation reveals excellent characteristics in adhesion and flexure resistance. Being feasible to various substrates and executable at ambient temperatures renders this approach a potential alternative for patterning metallic electrodes.

Polyaniline-Modified Oriented Graphene Hydrogel Film as the Free-Standing Electrode for Flexible Solid-State Supercapacitors.

Science.gov (United States)

Du, Pengcheng; Liu, Huckleberry C; Yi, Chao; Wang, Kai; Gong, Xiong

2015-11-04

In this study, we report polyaniline (PANI)-modified oriented graphene hydrogel (OGH) films as the free-standing electrode for flexible solid-state supercapacitors (SCs). The OGH films are prepared by a facile filtration method using chemically converted graphene sheets and then introduced to PANI on the surface of OGH films by in situ chemical polymerization. The PANI-modified OGH films possess high flexibility, high electrical conductivity, and mechanical robustness. The flexible solid-state SCs based on the PANI-modified OGH films exhibit a specific capacitance of 530 F/g, keeping 80% of its original value up to 10 000 charge-discharge cycles at the current density of 10 A/g. Remarkably, the flexible solid-state SCs maintain ∼100% capacitance retention bent at 180° for 250 cycles. Moreover, the flexible solid-state SCs are further demonstrated to be able to light up a red-light-emitting diode. These results indicate that the flexible solid-state SCs based on PANI-modified OGH films as the free-standing electrode have potential applications as energy-storage devices.

Fabrication of La-doped TiO2 Film Electrode and investigation of its electrocatalytic activity for furfural reduction

International Nuclear Information System (INIS)

Wang, Fengwu; Xu, Mai; Wei, Lin; Wei, Yijun; Hu, Yunhu; Fang, Wenyan; Zhu, Chuan Gao

2015-01-01

Lanthanum trivalent ions (La 3+ ) doped nano-TiO 2 film electrode was prepared by the sol–gel method. The prepared electrode was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The electrocatalytic properties of the roughened TiO 2 film electrode towards the electrocatalytic reduction of furfural to furfural alcohol were evaluated by CV and preparative electrolysis experiments. The results of the optimum molar ratio of La: Ti was 0.005:1. Experimental evidence was presented that the La nano-TiO 2 electrode exhibited higher electrocatalytic activity for the reduction of furfural than the undoped nano-TiO 2 electrode in N,N-dimethylformamide medium. Bulk electrolysis studies were also carried out for the reduction of furfural and the product was confirmed by NMR

Preparation of TiO{sub 2}/boron-doped diamond/Ta multilayer films and use as electrode materials for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Shi, Chao, E-mail: sc_sq1988@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Hongji, E-mail: hongjili@yeah.net [Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Cuiping, E-mail: licp226@126.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Li, Mingji, E-mail: limingji@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Qu, Changqing, E-mail: quchangqing@tjut.edu.cn [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Yang, Baohe, E-mail: bhyang207@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China)

2015-12-01

Highlights: • BDD film was deposited on Ta substrate by hot filament CVD method. • Ti layer was deposited on BDD film by radio frequency magnetron sputtering. • Nanostructured TiO{sub 2}/BDD/nanoporous Ta films were prepared. • The films exhibit good capacitance performance and excellent stability. - Abstract: We report nanostructured TiO{sub 2}/boron-doped diamond (BDD)/Ta multilayer films and their electrochemical performances as supercapacitor electrodes. The BDD films were grown on Ta substrates using electron-assisted hot filament chemical vapor deposition. Ti metal layers were deposited on the BDD surfaces by radio frequency magnetron sputtering, and nanostructured TiO{sub 2}/BDD/Ta thin films were prepared by electrochemical etching and thermal annealing. The successful formation of TiO{sub 2} and Ta layered nanostructures was demonstrated using scanning electron and transmission electron microscopies. The electrochemical responses of these electrodes were evaluated by examining their use as electrical double-layer capacitors, using cyclic voltammetry, and galvanostatic charge/discharge and impedance measurements. When the TiO{sub 2}/BDD/Ta film was used as the working electrode with 0.1 M Na{sub 2}SO{sub 4} as the electrolyte, the capacitor had a specific capacitance of 5.23 mF cm{sup −2} at a scan rate of 5 mV s{sup −1} for a B/C ratio of 0.1% w/w. Furthermore, the TiO{sub 2}/BDD/Ta film had improved electrochemical stability, with a retention of 89.3% after 500 cycles. This electrochemical behavior is attributed to the quality of the BDD, the surface roughness and electrocatalytic activities of the TiO{sub 2} layer and Ta nanoporous structures, and the synergies between them. These results show that TiO{sub 2}/BDD/Ta films are promising as capacitor electrodes for special applications.

Studies of pyrrole black electrodes as possible battery positive electrodes

Energy Technology Data Exchange (ETDEWEB)

Mengoli, G.; Musiani, M.M.; Fleischmann, M.; Pletcher, D.

1984-05-01

It is shown that a polypyrrole, pyrrole black, may be formed anodically in several aqueous acids. The polypyrrole film shows a redox couple at less positive potentials than that required to form the film and the charge associated with these reduction and oxidation processes together with their stabilty to cycling varies with the anion in solution and the potential where the polypyrrole is formed; over-oxidation of the film caused by taking its potential too positive has a particularly disadvantageous affect. In the acids HBr and HI, the polypyrrole films can act as a storage medium for Br/sub 2/ or I/sub 2/ so that they may be used as a substrate for a X/sub 2//X/sup -/ electrode. Such electrodes may be charge/discharge cycled and the pyrrole/Br/sub 2/ electrode shows promise as a battery positive electrode.

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.

Annealing Effect on the Photoelectrochemical Properties of BiVO_4 Thin Film Electrodes

International Nuclear Information System (INIS)

Siti Nur Farhana Mohd Nasir; Mohd Asri Mat Teridi; Mehdi Ebadi; Sagu, J.S.

2015-01-01

Monoclinic bismuth vanadate (BiVO_4) thin film electrodes were fabricated on fluorine-doped tin oxide via aerosol-assisted chemical vapour deposition (AACVD). Annealing and without annealing effect of thin films were analysed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible spectrophotometry (UV-Vis) and current voltage measurement. All BiVO_4 thin films showed an anodic photocurrent. The sample of BiVO_4 annealed at 400 degree Celsius exhibited the highest photocurrent density of 0.44 mAcm"-"2 vs. Ag/ AgCl at 1.23 V. (author)

Layered Cu-based electrode for high-dielectric constant oxide thin film-based devices

International Nuclear Information System (INIS)

Fan, W.; Saha, S.; Carlisle, J.A.; Auciello, O.; Chang, R.P.H.; Ramesh, R.

2003-01-01

Ti-Al/Cu/Ta multilayered electrodes were fabricated on SiO 2 /Si substrates by ion beam sputtering deposition, to overcome the problems of Cu diffusion and oxidation encountered during the high dielectric constant (κ) materials integration. The Cu and Ta layers remained intact through the annealing in oxygen environment up to 600 deg. C. The thin oxide layer, formed on the Ti-Al surface, effectively prevented the oxygen penetration toward underneath layers. Complex oxide (Ba x Sr 1-x )TiO 3 (BST) thin films were grown on the layered Ti-Al/Cu/Ta electrodes using rf magnetron sputtering. The deposited BST films exhibited relatively high permittivity (150), low dielectric loss (0.007) at zero bias, and low leakage current -8 A/cm 2 at 100 kV/cm

A novel in situ electrochemical NMR cell with a palisade gold film electrode

Science.gov (United States)

Ni, Zu-Rong; Cui, Xiao-Hong; Cao, Shuo-Hui; Chen, Zhong

2017-08-01

In situ electrochemical nuclear magnetic resonance (EC-NMR) has attracted considerable attention because of its ability to directly observe real-time electrochemical processes. Therefore, minimizing the incompatibility between the electrochemical device and NMR detection has become an important challenge. A circular thin metal film deposited on the outer surface of a glass tube with a thickness considerably less than the metal skin depth is considered to be the ideal working electrode. In this study, we demonstrate that such a thin film electrode still has a great influence on the radio frequency field homogeneity in the detective zone of the NMR spectrometer probe and provide theoretical and experimental confirmation of its electromagnetic shielding. Furthermore, we propose a novel palisade gold film device to act as the working electrode. The NMR nutation behavior of protons shows that the uniformity of the radio frequency field is greatly improved, increasing the sensitivity in NMR detection. Another advantage of the proposed device is that an external reference standard adapted to the reaction compound can be inserted as a probe to determine the fluctuation of the physico-chemical environment and achieve high-accuracy quantitative NMR analysis. A three-chamber electrochemical device based on the palisade gold film design was successfully fabricated and the in situ electrochemical NMR performance was validated in a standard 5 mm NMR probe by acquiring voltammograms and high-resolution NMR spectra to characterize the electrochemically generated species. The evolution of in situ EC-NMR spectrum monitoring of the redox transformation between p-benzoquinone and hydroquinone demonstrates the ability of the EC-NMR device to simultaneously quantitatively determine the reactants and elucidate the reaction mechanism at the molecular level.

A novel in situ electrochemical NMR cell with a palisade gold film electrode

Directory of Open Access Journals (Sweden)

Zu-Rong Ni

2017-08-01

Full Text Available In situ electrochemical nuclear magnetic resonance (EC-NMR has attracted considerable attention because of its ability to directly observe real-time electrochemical processes. Therefore, minimizing the incompatibility between the electrochemical device and NMR detection has become an important challenge. A circular thin metal film deposited on the outer surface of a glass tube with a thickness considerably less than the metal skin depth is considered to be the ideal working electrode. In this study, we demonstrate that such a thin film electrode still has a great influence on the radio frequency field homogeneity in the detective zone of the NMR spectrometer probe and provide theoretical and experimental confirmation of its electromagnetic shielding. Furthermore, we propose a novel palisade gold film device to act as the working electrode. The NMR nutation behavior of protons shows that the uniformity of the radio frequency field is greatly improved, increasing the sensitivity in NMR detection. Another advantage of the proposed device is that an external reference standard adapted to the reaction compound can be inserted as a probe to determine the fluctuation of the physico-chemical environment and achieve high-accuracy quantitative NMR analysis. A three-chamber electrochemical device based on the palisade gold film design was successfully fabricated and the in situ electrochemical NMR performance was validated in a standard 5 mm NMR probe by acquiring voltammograms and high-resolution NMR spectra to characterize the electrochemically generated species. The evolution of in situ EC-NMR spectrum monitoring of the redox transformation between p-benzoquinone and hydroquinone demonstrates the ability of the EC-NMR device to simultaneously quantitatively determine the reactants and elucidate the reaction mechanism at the molecular level.

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

Electroplating of CdTe Thin Films from Cadmium Sulphate Precursor and Comparison of Layers Grown by 3-Electrode and 2-Electrode Systems

Directory of Open Access Journals (Sweden)

Imyhamy M. Dharmadasa

2017-01-01

Full Text Available Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E and two-electrode (2E systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system.

Ready fabrication of thin-film electrodes from building nanocrystals for micro-supercapacitors.

Science.gov (United States)

Chen, Zheng; Weng, Ding; Wang, Xiaolei; Cheng, Yanhua; Wang, Ge; Lu, Yunfeng

2012-04-18

Thin-film pseudocapacitor electrodes with ultrafast lithium storage kinetics, high capacitance and excellent cycling stability were fabricated from monodispersed TiO(2) building nanocrystals, providing a novel approach towards next-generation micro-supercapacitor applications. This journal is © The Royal Society of Chemistry 2012

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...... 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....

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.

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).

Highly sensitive determination of hydroxylamine using fused gold nanoparticles immobilized on sol-gel film modified gold electrode

Energy Technology Data Exchange (ETDEWEB)

Kannan, P. [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Dindigul, Tamilnadu (India); John, S. Abraham, E-mail: abrajohn@yahoo.co.in [Department of Chemistry, Gandhigram Rural University, Gandhigram 624302, Dindigul, Tamilnadu (India)

2010-03-24

We are reporting the highly sensitive determination of hydroxylamine (HA) using 2-mercapto-4-methyl-5-thiazoleacetic acid (TAA) capped fused spherical gold nanoparticles (AuNPs) modified Au electrode. The fused TAA-AuNPs were immobilized on (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel film, which was pre-assembled on Au electrode. The immobilization of fused TAA-AuNPs on MPTS sol-gel film was confirmed by UV-vis absorption spectroscopy and atomic force microscopy (AFM). The AFM image showed that the AuNPs retained the fused spherical morphology after immobilized on sol-gel film. The fused TAA-AuNPs on MPTS modified Au electrode were used for the determination of HA in phosphate buffer (PB) solution (pH = 7.2). When compared to bare Au electrode, the fused AuNPs modified electrode not only shifted the oxidation potential of HA towards less positive potential but also enhanced its oxidation peak current. Further, the oxidation of HA was highly stable at fused AuNPs modified electrode. Using amperometric method, determination of 17.5 nM HA was achieved for the first time. Further, the current response of HA increases linearly while increasing its concentration from 17.5 nM to 22 mM and a detection limit was found to be 0.39 nM (S/N = 3). The present modified electrode was also successfully used for the determination of 17.5 nM HA in the presence of 200-fold excess of common interferents such as urea, NO{sub 2}{sup -}, NH{sub 4}{sup +}, oxalate, Mn{sup 2+}, Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Ba{sup 2+} and Cu{sup 2+}. The practical application of the present modified electrode was demonstrated by measuring the concentration of HA in ground water samples.

Understanding anodic wear at boron doped diamond film electrodes

International Nuclear Information System (INIS)

Chaplin, Brian P.; Hubler, David K.; Farrell, James

2013-01-01

This research investigated the mechanisms associated with anodic wear of boron-doped diamond (BDD) film electrodes. Cyclic voltammetry (CV), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS) were used to measure changes in electrode response and surface chemistry as a function of the charge passed and applied current density. Density functional theory (DFT) modeling was used to evaluate possible reaction mechanisms. The initial hydrogen-terminated surface was electrochemically oxidized at lower potentials than water oxidation (≤ 1.83 V/SHE), and was not catalyzed by the hydrogen-terminated surface. In the region where water oxidation produces hydroxyl radicals (OH·), the hydrogen-terminated surface may also be oxidized by chemical reaction with OH·. Oxygen atoms became incorporated into the surface via reaction of carbon atoms with OH·, forming both C = O and C-OH functional groups, that were also detected by XPS measurements. Experimental and DFT modeling results indicate that the oxygenated diamond surface lowers the potential for activationless water oxidation from 2.74 V/SHE for the hydrogen terminated surface to 2.29 V/SHE for the oxygenated surface. Electrode wear was accelerated at high current densities (i.e., 500 mA cm −2 ), where SEM results indicated oxidation of the BDD film resulted in significant surface roughening. These results are supported by EIS measurements that document an increase in the double-layer capacitance as a function of the charge passed. DFT simulations provide a possible mechanism that explains the observed diamond oxidation. DFT simulation results indicate that BDD edge sites (=CH 2 ) can be converted to COOH functional groups, which are further oxidized via reactions with OH· to form H 2 CO 3(aq.) with an activation energy of 58.9 kJ mol −1

Effect of multi-layered bottom electrodes on the orientation of strontium-doped lead zirconate titanate thin films

Energy Technology Data Exchange (ETDEWEB)

Bhaskaran, M. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)], E-mail: madhu.bhaskaran@gmail.com; Sriram, S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia); Mitchell, D.R.G.; Short, K.T. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, New South Wales 2234 (Australia); Holland, A.S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)

2008-09-30

This article discusses the results from X-ray diffraction (XRD) analysis of piezoelectric strontium-doped lead zirconate titanate (PSZT) thin films deposited on multi-layer coatings on silicon. The films were deposited by RF magnetron sputtering on a metal coated substrate. The aim was to exploit the pronounced piezoelectric effect that is theoretically expected normal to the substrate. This work highlighted the influence that the bottom electrode architecture exerts on the final crystalline orientation of the deposited thin films. A number of bottom electrode architectures were used, with the uppermost metal layer on which PSZT was deposited being gold or platinum. The XRD analysis revealed that the unit cell of the PSZT thin films deposited on gold and on platinum were deformed, relative to expected unit cell dimensions. Experimental results have been used to estimate the unit cell parameters. The XRD results were then indexed based on these unit cell parameters. The choice and the thickness of the intermediate adhesion layers influenced the relative intensity, and in some cases, the presence of perovskite peaks. In some cases, undesirable reactions between the bottom electrode layers were observed, and layer architectures to overcome these reactions are also discussed.

Novel layered polyaniline-poly(hydroquinone)/graphene film as supercapacitor electrode with enhanced rate performance and cycling stability.

Science.gov (United States)

Ren, Lijun; Zhang, Gaini; Lei, Ji; Wang, Yan; Hu, Dengwei

2018-02-15

It is a challenge to fabricate polyaniline (PANI) materials with high rate performance and excellent stability. Herein a new special supercapacitor electrode material of polyaniline-poly(hydroquinone)/graphene (PANI-PHQ/RGO) film with layered structure was prepared by chemical oxidative polymerization of aniline and hydroquinone (H 2 Q) in the presence of RGO hydrogel film. The synergistic effect and loose layered structure of the composite film facilitate fast diffusion and transportation of electrolyte ions through unimpeded channels during rapid charge-discharge process, resulting in high rate capability and stable cycling performance. As a result, the PANI-PHQ/RGO-61 film electrode exhibited 356 F g -1 at a current density of 0.5 A g -1 and high capacitance retention of 83% from 0.5 to 30 A g -1 . Moreover, it presented an excellent cycling stability with 94% of capacitance retention in comparison with 60% of pure PANI electrode and an outstanding Coulombic efficiency of 99% after 1000 cycles of galvanostatic charge-discharge. These superior electrocapacitive properties make it one of promising candidates for electrochemical energy storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Glassy carbon electrodes modified with a film of nanodiamond-graphite/chitosan: Application to the highly sensitive electrochemical determination of Azathioprine

International Nuclear Information System (INIS)

Shahrokhian, Saeed; Ghalkhani, Masoumeh

2010-01-01

A novel modified glassy carbon electrode with a film of nanodiamond-graphite/chitosan is constructed and used for the sensitive voltammetric determination of azathioprine (Aza). The surface morphology and thickness of the film modifier are characterized using atomic force microscopy. The electrochemical response characteristics of the electrode toward Aza are investigated by means of cyclic voltammetry. The modified electrode showed an efficient catalytic role for the electrochemical reduction of Aza, leading to a remarkable decrease in reduction overpotential and enhancement of the kinetics of the electrode reaction with a significant increase of peak current. The effects of experimental variables, such as the deposited amount of modifier suspension, the pH of the supporting electrolyte, the accumulation potential and time were investigated. Under optimal conditions, the modified electrode showed a wide linear response to the concentration of Aza in the range of 0.2-100 μM with a detection limit of 65 nM. The prepared modified electrode showed several advantages: simple preparation method, high stability and uniformity in the composite film, high sensitivity, excellent catalytic activity in physiological conditions and good reproducibility. The modified electrode can be successfully applied to the accurate determination of trace amounts of Aza in pharmaceutical and clinical preparations.

Glassy carbon electrodes modified with a film of nanodiamond-graphite/chitosan: Application to the highly sensitive electrochemical determination of Azathioprine

Energy Technology Data Exchange (ETDEWEB)

Shahrokhian, Saeed, E-mail: shahrokhian@sharif.ed [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Institute for Nanoscience and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Ghalkhani, Masoumeh [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of)

2010-04-15

A novel modified glassy carbon electrode with a film of nanodiamond-graphite/chitosan is constructed and used for the sensitive voltammetric determination of azathioprine (Aza). The surface morphology and thickness of the film modifier are characterized using atomic force microscopy. The electrochemical response characteristics of the electrode toward Aza are investigated by means of cyclic voltammetry. The modified electrode showed an efficient catalytic role for the electrochemical reduction of Aza, leading to a remarkable decrease in reduction overpotential and enhancement of the kinetics of the electrode reaction with a significant increase of peak current. The effects of experimental variables, such as the deposited amount of modifier suspension, the pH of the supporting electrolyte, the accumulation potential and time were investigated. Under optimal conditions, the modified electrode showed a wide linear response to the concentration of Aza in the range of 0.2-100 muM with a detection limit of 65 nM. The prepared modified electrode showed several advantages: simple preparation method, high stability and uniformity in the composite film, high sensitivity, excellent catalytic activity in physiological conditions and good reproducibility. The modified electrode can be successfully applied to the accurate determination of trace amounts of Aza in pharmaceutical and clinical preparations.

Trans-membrane electron transfer in red blood cells immobilized in a chitosan film on a glassy carbon electrode

International Nuclear Information System (INIS)

Yu, Chunmei; Wang, Li; Zhu, Zhenkun; Bao, Ning; Gu, Haiying

2014-01-01

We have studied the trans-membrane electron transfer in human red blood cells (RBCs) immobilized in a chitosan film on a glassy carbon electrode (GCE). Electron transfer results from the presence of hemoglobin (Hb) in the RBCs. The electron transfer rate (k s ) of Hb in RBCs is 0.42 s −1 , and <1.13 s −1 for Hb directly immobilized in the chitosan film. Only Hb molecules in RBCs that are closest to the plasma membrane and the surface of the electrode can undergo electron transfer to the electrode. The immobilized RBCs displayed sensitive electrocatalytic response to oxygen and hydrogen peroxide. It is believed that this cellular biosensor is of potential significance in studies on the physiological status of RBCs based on observing their electron transfer on the modified electrode. (author)

Investigation of passivating films on Li-electrode by the method of photoelectronic emission

International Nuclear Information System (INIS)

Nimon, E.S.; Churikov, A.V.; Gamayunova, I.M.; L'vov, A.L.

1995-01-01

Spectral dependences of photoeffect under conditions of pulsed illumination by visible and near IR radiation of Li-electrode surface in propylene carbonate and thionyl chloride base solutions have been studied. Photoemission of electrons from lithium to passivating films on its surface is the primary stage of the cathode photoeffect detected. The method of electron photoemission is used to obtain information on the composition and characteristics of the passivating films. 21 refs., 7 figs., 1 tab

Potentiodynamic formation of gold nanoparticles film on glassy carbon electrode using aminophenyl diazonium cations grafted gold nanoparticles: Determination of histamine H2 receptor antagonist

International Nuclear Information System (INIS)

Kesavan, Srinivasan; Revin, S. Brillians; John, S. Abraham

2014-01-01

Graphical abstract: - Highlights: • Grafting based AuNPs were synthesized in aqueous medium by spontaneous grafting. • GC/ITO electrode was modified with AuNPs film by potentiodynamic method. • AuNPs film modified electrode was characterized by XPS, AFM and CV. • Simultaneous determination of ranitidine and paracetamol was demonstrated. • Practical application was demonstrated in commercial drugs. - Abstract: The aminophenyl (AP) functionalized AuNPs (AP-AuNPs) were synthesized in aqueous medium by spontaneous grafting method and were used for the formation of AuNPs film on glassy carbon (GC) and indium tin oxide (ITO) surfaces by potentiodynamic method. The formed AP-AuNPs film modified electrodes were characterized by cyclic voltammetry (CV), atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). EIS studies show that the electron transfer reaction of [Fe(CN) 6 ] 3-/4− was higher at the AP-AuNPs film modified electrode (1.58 × 10 −4 cm s −1 ) than at bare (3.78 × 10 −5 cm s −1 ) GC electrode. The surface coverage of the AP-AuNPs film modified electrode was found to be 4.4 × 10 −10 mol cm −2 . The film formation takes place via -NH 2 groups of AP-AuNPs, which was confirmed by XPS from the observed peaks corresponding to =N-H (396.7 eV), -N-H (399.2 eV), -N = N- (400.2 eV) and -N + -H (403.3 eV). The AP-AuNPs film modified electrode was successfully utilized for the determination of histamine H 2 receptor antagonist ranitidine (RA). Further, the AP-AuNPs film modified electrode was effectively used for the selective determination of RA in the presence of 40-fold excess paracetamol. The present method was successfully used to determine the concentration of RA in commercial drugs

Depositing bulk or micro-scale electrodes

Science.gov (United States)

Shah, Kedar G.; Pannu, Satinderpall S.; Tolosa, Vanessa; Tooker, Angela C.; Sheth, Heeral J.; Felix, Sarah H.; Delima, Terri L.

2016-11-01

Thicker electrodes are provided on microelectronic device using thermo-compression bonding. A thin-film electrical conducting layer forms electrical conduits and bulk depositing provides an electrode layer on the thin-film electrical conducting layer. An insulating polymer layer encapsulates the electrically thin-film electrical conducting layer and the electrode layer. Some of the insulating layer is removed to expose the electrode layer.

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

Energy Technology Data Exchange (ETDEWEB)

Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

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.

A complicated biocomputing system based on multi-responsive P(NIPAM-co-APBA) copolymer film electrodes and electrocatalysis of NADH.

Science.gov (United States)

Liang, Jiying; Yu, Xue; Yang, Tiangang; Li, Menglu; Shen, Li; Jin, Yue; Liu, Hongyun

2017-08-23

In this paper, poly(N-isopropylacrylamide-co-3-aminophenylboronic acid) (P(NIPAM-co-APBA)) copolymer films were successfully electropolymerized on the Au electrode surface. The electroactive probe ferrocene carboxylic acid (FCA) in solution showed reversible thermal-, glucose- and pH-responsive on-off cyclic voltammetric (CV) behaviors at the film electrodes. The comparative experiments demonstrated that the thermo-responsive property of the film electrode was ascribed to the PNIPAM component of the films, whereas the glucose- and pH-sensitive behaviors came from the PAPBA constituent. The reduced form of nicotinamide adenine dinucleotide (NADH) could be electrocatalytically oxidized by FCA at the film electrodes, which would greatly amplify the multi-responsive CV signal difference between the on and off states. On the basis of these results, a binary 4-input/4-output logic circuit was fabricated with temperature, glucose, pH and NADH as inputs and the CV responses at 4 different levels as outputs. Moreover, a ternary CONSENSUS logic circuit was established on the same platform, which was the first report on the combination of ternary logic gate and bioelectrocatalysis without using enzymes. This work provided a novel idea for constructing complicated biocomputing systems by increasing the number of inputs/outputs with multi-sensitive interfaces and by designing new types of multi-valued logic gates on the basis of bioelectrocatalysis.

Probing-models for interdigitated electrode systems with ferroelectric thin films

Science.gov (United States)

Nguyen, Cuong H.; Nigon, Robin; Raeder, Trygve M.; Hanke, Ulrik; Halvorsen, Einar; Muralt, Paul

2018-05-01

In this paper, a new method to characterize ferroelectric thin films with interdigitated electrodes is presented. To obtain accurate properties, all parasitic contributions should be subtracted from the measurement results and accurate models for the ferroelectric film are required. Hence, we introduce a phenomenological model for the parasitic capacitance. Moreover, two common analytical models based on conformal transformations are compared and used to calculate the capacitance and the electric field. With a thin film approximation, new simplified electric field and capacitance formulas are derived. By using these formulas, more consistent CV, PV and stress-field loops for samples with different geometries are obtained. In addition, an inhomogeneous distribution of the permittivity due to the non-uniform electric field is modelled by finite element simulation in an iterative way. We observed that this inhomogeneous distribution can be treated as a homogeneous one with an effective value of the permittivity.

Fabrication and characterization of implantable and flexible nerve cuff electrodes with Pt, Ir and IrOx films deposited by RF sputtering

International Nuclear Information System (INIS)

Lee, Soo Hyun; Jung, Jung Hwan; Chae, Youn Mee; Kang, Ji Yoon; Suh, Jun-Kyo Francis

2010-01-01

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 (IrO x ) 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 IrO x 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 IrO x films, the electrochemical properties were strongly affected by the working pressure as well as the Ar:O 2 gas ratio. The IrO x film deposited with an Ar:O 2 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.

Contact Resistance Reduction of ZnO Thin Film Transistors (TFTs) with Saw-Shaped Electrode

KAUST Repository

Park, Woojin

2018-05-15

We report a saw-shaped electrode architecture ZnO thin film transistor (TFT) for effectively increase channel width. Such a saw-shaped electrode has ~2 times longer contact line at the contact metal/ZnO channel junction. We experimentally observed an enhancement in the output drive current by 50% and reduction in the contact resistance by over 50%, when compared to a typical shaped electrode ZnO TFT consuming the same chip area. This performance enhancement is attributed to extension of channel width. This technique can contribute to device performance enhancement and especially reduction in the contact resistance which is a serious challenge.

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%)

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

International Nuclear Information System (INIS)

Lee, So Hee; Lim, Sooman; Kim, Haekyoung

2015-01-01

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 □ −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 □ −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 ☐ −1 ) and high transmittance (87.6%)

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

Energy Technology Data Exchange (ETDEWEB)

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

2003-08-01

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 attributed to the more active participation of the extruded copper in the functioning of the electrode. The continual and extensive extrusion of copper on cycling the cells leads to the isolation of Li3Sb particles and a consequent formation of Sb. Improved cycling stability of both types of electrodes was obtained when cells were cycled between 0.65 and 1.4 V. A low-capacity lithium-ion cell with Cu2Sb and LiNi0.8Co0.15Al0.05O2 electrodes, laminated from powders, shows excellent cycling stability over the voltage range 3.15 - 2.2 V, the potential difference corresponding to approximately 0.65-1.4 V for the Cu2Sb electrode vs. Li/Li+. Chemical self-discharge of lithiated Cu2Sb electrodes by reaction with the electrolyte was severe when cells were allowed to relax on open circuit after reaching a lower voltage limit of 0.1 V. The solid electrolyte interphase (SEI) layer formed on Cu2Sb electrodes after cells had been cycled between 1.4 and 0.65 V vs. Li/Li+ was characterized by Fourier-transform infrared spectroscopy; the SEI layer contributes to the large irreversible capacity loss on the initial cycle of these cells. The data contribute to a better understanding of the electrochemical behavior of intermetallic electrodes in rechargeable lithium batteries.

Highly Conductive Transparent and Flexible Electrodes Including Double-Stacked Thin Metal Films for Transparent Flexible Electronics.

Science.gov (United States)

Han, Jun Hee; Kim, Do-Hong; Jeong, Eun Gyo; Lee, Tae-Woo; Lee, Myung Keun; Park, Jeong Woo; Lee, Hoseung; Choi, Kyung Cheol

2017-05-17

To keep pace with the era of transparent and deformable electronics, electrode functions should be improved. In this paper, an innovative structure is suggested to overcome the trade-off between optical and electrical properties that commonly arises with transparent electrodes. The structure of double-stacked metal films showed high conductivity (electronics are expected.

NiCo2O4 nanosheets in-situ grown on three dimensional porous Ni film current collectors as integrated electrodes for high-performance supercapacitors

Science.gov (United States)

Wang, Tao; Guo, Ying; Zhao, Bo; Yu, Shuhui; Yang, Hai-Peng; Lu, Daniel; Fu, Xian-Zhu; Sun, Rong; Wong, Ching-Ping

2015-07-01

Three dimensional interconnected hierarchical porous Ni films are easily fabricated as effective current collectors through hydrogen bubble template electrochemical deposition. The binder-free integrated electrodes of spinel NiCo2O4 nanosheets directly coated the three dimensional porous Ni films are facilely obtained through successively electrochemical co-deposition of Ni/Co alloy layer then followed by subsequent annealing at 350 °C in air. Compared with NiCo2O4 nanosheets on smooth Ni foil or porous NiO/Ni film electrodes, the porous NiCo2O4/Ni integrated film electrodes for supercapacitors demonstrate remarkably higher area specific capacitance. The porous NiCo2O4/Ni film electrodes also exhibit excellent rate capability and cycling stability. The super electrochemical capacitive performances are attributed to the unique integrated architecture of NiCo2O4 nanosheets in-situ grown on three dimensional continuous hierarchical porous Ni collector collectors, which could provide large electrode-electrolyte interface area, high active sites, low contact resistance between current collector and active materials, fast electron conduction and ion/electrolyte diffusion.

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

Characteristics of RuO2-SnO2 nanocrystalline-embedded amorphous electrode for thin film microsupercapacitors

International Nuclear Information System (INIS)

Kim, Han-Ki; Choi, Sun-Hee; Yoon, Young Soo; Chang, Sung-Yong; Ok, Young-Woo; Seong, Tae-Yeon

2005-01-01

The characteristics of RuO 2 -SnO 2 nanocrystalline-embedded amorphous electrode, grown by DC reactive sputtering, was investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), and transmission electron diffraction (TED) examination results showed that Sn and Ru metal cosputtered electrode in O 2 /Ar ambient have RuO 2 -SnO 2 nanocrystallines in an amorphous oxide matrix. It is shown that the cyclic voltammorgram (CV) result of the RuO 2 -SnO 2 nanocrystalline-embedded amorphous film in 0.5 M H 2 SO 4 liquid electrolyte is similar to a bulk-type supercapacitor behavior with a specific capacitance of 62.2 mF/cm 2 μm. This suggests that the RuO 2 -SnO 2 nanocrystalline-embedded amorphous film can be employed in hybrid all-solid state energy storage devises as an electrode of supercapacitor

Synthesis and characterization of natural dye and counter electrode thin films with different carbon materials for dye-sensitized solar cells.

Science.gov (United States)

Chang, Ho; Chen, Tien-Li; Kao, Mu-Jung; Chen, Chih-Hao; Chien, Shu-Hua; Jiang, Lii-Jenq

2011-08-01

This study aims to deal with the film of the counter electrode of dye-sensitized solar cells (DSSCs) and the preparation, structure and characteristics of the extract of natural dye. This study adopts different commercial carbon materials such as black lead, carbon black and self-made TiO2-MWCNT compound nanoparticle as the film of the counter electrodes. Moreover, for the preparation of natural dyes, anthocyanins and chlorophyll dyes are extracted from mulberry and pomegranate respectively. Furthermore, the extracted anthocyanins and chlorophyll are blended into cocktail dye to complete the preparation of natural dye. Results show that the photoelectric conversion efficiency of the single-layer TiO2-MWCNT counter electrode film and the cocktail dye of the DSSCs is 0.462%.

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.

Design of a new hypoxanthine biosensor: xanthine oxidase modified carbon film and multi-walled carbon nanotube/carbon film electrodes.

Science.gov (United States)

Torres, A Carolina; Ghica, M Emilia; Brett, Christopher M A

2013-04-01

A new and simple-to-prepare hypoxanthine biosensor has been developed using xanthine oxidase (XOD) immobilised on carbon electrode surfaces. XOD was immobilised by glutaraldehyde cross-linking on carbon film (CF) electrodes and on carbon nanotube (CNT) modified CF (CNT/CF). A comparison of the performance of the two configurations was carried out by the current response using amperometry at fixed potential; the best characteristics being exhibited by XOD/CNT/CF modified electrodes. The effects of electrolyte pH and applied potential were evaluated, and a proposal is made for the enzyme mechanism of action involving competition between regeneration of flavin adenine dinucleotide and reduction of hydrogen peroxide. Under optimised conditions, the determination of hypoxanthine was carried out at -0.2 V vs. a saturated calomel electrode (SCE) with a detection limit of 0.75 μM on electrodes with CNT and at -0.3 V vs. SCE with a detection limit of 0.77 μM on electrodes without CNT. The applicability of the biosensor was verified by performing an interference study, reproducibility and stability were investigated, and hypoxanthine was successfully determined in sardine and shrimp samples.

Screen-printed carbon electrode modified on its surface with amorphous carbon nitride thin film: Electrochemical and morphological study

Energy Technology Data Exchange (ETDEWEB)

Ghamouss, F. [Universite de Nantes, UMR 6006-CNRS, FR-2465-CNRS, Laboratoire d' Analyse isotopique et Electrochimique de Metabolismes (LAIEM) (France); Tessier, P.-Y. [Universite de Nantes, UMR CNRS 6502, Institut des Materiaux Jean Rouxel - IMN Faculte des Sciences and des Techniques de Nantes, 2 rue de la Houssiniere, 44322 Nantes Cedex 3 (France); Djouadi, A. [Universite de Nantes, UMR CNRS 6502, Institut des Materiaux Jean Rouxel - IMN Faculte des Sciences and des Techniques de Nantes, 2 rue de la Houssiniere, 44322 Nantes Cedex 3 (France); Besland, M.-P. [Universite de Nantes, UMR CNRS 6502, Institut des Materiaux Jean Rouxel - IMN Faculte des Sciences and des Techniques de Nantes, 2 rue de la Houssiniere, 44322 Nantes Cedex 3 (France); Boujtita, M. [Universite de Nantes, UMR 6006-CNRS, FR-2465-CNRS, Laboratoire d' Analyse isotopique et Electrochimique de Metabolismes (LAIEM) (France)]. E-mail: mohammed.boujtita@univ-nantes.fr

2007-04-20

The surface of a screen-printed carbon electrode (SPCE) was modified by using amorphous carbon nitride (a-CN {sub x}) thin film deposited by reactive magnetron sputtering. Scanning electron microscopy and photoelectron spectroscopy measurements were used to characterise respectively the morphology and the chemical structure of the a-CN {sub x} modified electrodes. The incorporation of nitrogen in the amorphous carbon network was demonstrated by X ray photoelectron spectroscopy. The a-CN {sub x} layers were deposited on both carbon screen-printed electrode (SPCE) and silicon (Si) substrates. A comparative study showed that the nature of substrate, i.e. SPCE and Si, has a significant effect on both the surface morphology of deposited a-CN {sub x} film and their electrochemical properties. The improvement of the electrochemical reactivity of SPCE after a-CN {sub x} film deposition was highlighted both by comparing the shapes of voltammograms and calculating the apparent heterogeneous electron transfer rate constant.

Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes

DEFF Research Database (Denmark)

Holm, A.H.; Vase, K.H.; Winther-Jensen, Bjørn

2007-01-01

potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics...

Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes

Science.gov (United States)

Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

2016-02-01

We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials.

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

2015-04-08

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.

A flexible graphene/multiwalled carbon nanotube film as a high performance electrode material for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Xiangjun, Lu [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Dou Hui, E-mail: dh_msc@nuaa.edu.cn [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Bo, Gao [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Changzhou, Yuan [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Yang, Sudong; Liang, Hao; Laifa, Shen [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Zhang Xiaogang, E-mail: azhangxg@nuaa.edu.cn [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China)

2011-05-30

Highlights: > A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. > The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. > The freestanding GN/MWCNT film has a potential application in flexible energy storage devices. - Abstract: A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film has been fabricated by flow-directed assembly from a complex dispersion of graphite oxide (GO) and pristine MWCNTs followed by the use of gas-based hydrazine to reduce the GO into GN sheets. The GN/MWCNT (16 wt.% MWCNTs) film characterized by Fourier transformation infrared spectra, X-ray diffraction and scanning electron microscope has a layered structure with MWCNTs uniformly sandwiched between the GN sheets. The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets, increasing electrolyte/electrode contact area and facilitating transportation of electrolyte ion and electron into the inner region of electrode. Electrochemical data demonstrate that the GN/MWCNT film possesses a specific capacitance of 265 F g{sup -1} at 0.1 A g{sup -1} and a good rate capability (49% capacity retention at 50 A g{sup -1}), and displays an excellent specific capacitance retention of 97% after 2000 continuous charge/discharge cycles. The results of electrochemical measurements indicate that the freestanding GN/MWCNT film has a potential application in flexible energy storage devices.

A flexible graphene/multiwalled carbon nanotube film as a high performance electrode material for supercapacitors

International Nuclear Information System (INIS)

Lu Xiangjun; Dou Hui; Gao Bo; Yuan Changzhou; Yang, Sudong; Hao Liang; Shen Laifa; Zhang Xiaogang

2011-01-01

Highlights: → A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. → The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. → The freestanding GN/MWCNT film has a potential application in flexible energy storage devices. - Abstract: A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film has been fabricated by flow-directed assembly from a complex dispersion of graphite oxide (GO) and pristine MWCNTs followed by the use of gas-based hydrazine to reduce the GO into GN sheets. The GN/MWCNT (16 wt.% MWCNTs) film characterized by Fourier transformation infrared spectra, X-ray diffraction and scanning electron microscope has a layered structure with MWCNTs uniformly sandwiched between the GN sheets. The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets, increasing electrolyte/electrode contact area and facilitating transportation of electrolyte ion and electron into the inner region of electrode. Electrochemical data demonstrate that the GN/MWCNT film possesses a specific capacitance of 265 F g -1 at 0.1 A g -1 and a good rate capability (49% capacity retention at 50 A g -1 ), and displays an excellent specific capacitance retention of 97% after 2000 continuous charge/discharge cycles. The results of electrochemical measurements indicate that the freestanding GN/MWCNT film has a potential application in flexible energy storage devices.

Preparation and characterization of flexible asymmetric supercapacitors based on transition-metal-oxide nanowire/single-walled carbon nanotube hybrid thin-film electrodes.

Science.gov (United States)

Chen, Po-Chiang; Shen, Guozhen; Shi, Yi; Chen, Haitian; Zhou, Chongwu

2010-08-24

In the work described in this paper, we have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on transition-metal-oxide nanowire/single-walled carbon nanotube (SWNT) hybrid thin-film electrodes. These hybrid nanostructured films, with advantages of mechanical flexibility, uniform layered structures, and mesoporous surface morphology, were produced by using a filtration method. Here, manganese dioxide nanowire/SWNT hybrid films worked as the positive electrode, and indium oxide nanowire/SWNT hybrid films served as the negative electrode in a designed ASC. In our design, charges can be stored not only via electrochemical double-layer capacitance from SWNT films but also through a reversible faradic process from transition-metal-oxide nanowires. In addition, to obtain stable electrochemical behavior during charging/discharging cycles in a 2 V potential window, the mass balance between two electrodes has been optimized. Our optimized hybrid nanostructured ASCs exhibited a superior device performance with specific capacitance of 184 F/g, energy density of 25.5 Wh/kg, and columbic efficiency of approximately 90%. In addition, our ASCs exhibited a power density of 50.3 kW/kg, which is 10-fold higher than obtained in early reported ASC work. The high-performance hybrid nanostructured ASCs can find applications in conformal electrics, portable electronics, and electrical vehicles.

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)

Wang, Pen-Cheng; Yu, Jing-Yu; Li, Kuan-Hsun

2011-01-01

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 □ -1 and 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.

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.

Nd3-xBixFe4GaO12 (x = 2, 2.5 films on glass substrates prepared by MOD method

Directory of Open Access Journals (Sweden)

Yoshida T.

2014-07-01

Full Text Available We studied Nd3-XBiXFe4GaO12 films to obtain perpendicular magnetic anisotropy as well as large Faraday effect. NdBi2Fe4GaO12 (Bi2:NIGG and Nd0.5Bi2.5Fe4GaO12 (Bi2.5:NIGG films were obtained on Nd2BiFe4GaO12 (Bi1:NIGG layer prepared on glass substrates by metal-organic decomposition (MOD method. Bi2:NIGG and Bi2.5:NIGG films showed large Faraday rotation angles of 7.5 and 10.5 degree/µm, at a wavelength of 520 nm, respectively. Those films have perpendicular magnetic anisotropy with a coercivity of 350 Oe and a saturation magnetic field of 730 Oe.

Application of thin film mercury electrodes and solid amalgam electrodes in electrochemical analysis of the nucleic acids components: detection of the two-dimensional phase transients of adenosine

Czech Academy of Sciences Publication Activity Database

Hasoň, Stanislav; Vetterl, Vladimír

2004-01-01

Roč. 63, 1-2 (2004), s. 37-41 ISSN 1567-5394 R&D Projects: GA AV ČR KJB4004305; GA AV ČR IBS5004107 Institutional research plan: CEZ:AV0Z5004920 Keywords : mercury film electrodes * solid amalgam electrodes * roughness Subject RIV: BO - Biophysics Impact factor: 2.261, year: 2004

Charge transfer processes on electrodes modified by polymer films of metal complexes with Schiff bases

International Nuclear Information System (INIS)

Levin, O.V.; Karushev, M.P.; Timonov, A.M.; Alekseeva, E.V.; Zhang, Shuanghua; Malev, V.V.

2013-01-01

Electrochemical properties of glassy carbon electrodes modified by two polymer films of different nickel complexes with Schiff base ligands containing methoxy substituents in their aromatic parts were studied in acetonitrile solutions with cyclic voltammetry, quartz crystal microbalance, atomic force microscopy, and impedance spectroscopy. It was observed that introduction of such substituents leads to a noticeable splitting of cycling voltammetric curves into at least two ox/red transitions. In addition, solvent flows accompanying the counter-ions ones during charging/discharge processes within the films appeared significantly greater than those observed in the case of non-substituted ligands. The obtained impedance results as a whole were satisfactorily treated in scope of the so-called model of homogeneous films with two kinds of charge carriers. However, determinations of the Warburg constant as a function of the electrode potential require additional verifications, at least in the ranges of overlapping ox/red transitions. In particular, it was established that in this region the impedance frequency dependence was some superposition of the diffusion (Warburg) and the pseudo-capacitive constituents. This, most likely, resulted from the presence of three kinds of charge carriers in the film interior

Voltammetric Determination of Lead (II) and Cadmium (II) Using a Bismuth Film Electrode Modified with Mesoporous Silica Nanoparticles

International Nuclear Information System (INIS)

Yang, Die; Wang, Liang; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

2014-01-01

A new chemically modified glassy carbon electrode based on bismuth film coated mesoporous silica nanoparticles was developed and evaluated for reliable quantification of trace Pb 2+ and Cd 2+ by anodic stripping square wave voltammetry in natural water samples. Compared with conventional bismuth film electrodes or bismuth nanoparticles modified electrodes, this electrode exhibited significantly improved sensitivity and stability for Pb 2+ and Cd 2+ detection. The key experimental parameters related to the fabrication of the electrode and the voltammetric measurements were optimized on the basis of the stripping signals, where the peak currents increased linearly with the metal concentrations in a range of 2-150 μg L −1 with a detect limit of 0.2 μg L −1 for Pb 2+ , and 0.6 μg L −1 for Cd 2+ for 120s deposition. Good reproducibility was achieved on both single and equally prepared electrodes. In addition, scanning electron microscopy reveals that fibril-like bismuth structures were formed on silica nanoparticles, which could be responsible for the improved voltammetric performance due to the enhanced surface area. Finally, the developed electrode was applied to determine Pb 2+ and Cd 2+ in water samples, indicating that this electrode was sensitive, reliable and effective for the simultaneous determination of Pb 2+ and Cd 2+

Solid-state electrochromic cell with anodic iridium oxide film electrodes

International Nuclear Information System (INIS)

Dautremont-Smith, W.C.; Beni, G.; Schiavone, L.M.; Shay, J.L.

1979-01-01

A new solid-state electrochromic cell has been fabricated using an anodic iridium oxide film (AIROF) display electrode. The cell has the symmetric sandwich structure AIROFvertical-barNafionvertical-barAIROF, with the Nafion solid electrolyte opacified by an in situ precipitation technique. A symmetric square-wave voltage of 1.5 V amplitude produces clearly perceivable color changes from pale to dark blue-gray in approx. =1 sec when viewed in diffuse reflection. Good open-circuit optical memory is exhibited:

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

International Nuclear Information System (INIS)

Pan Mingfei; Fang Guozhen; Liu Bing; Qian Kun; Wang Shuo

2011-01-01

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 (r 2 = 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.

Stripping chronopotentiometric measurements of lead(II) and cadmium(II) in soils extracts and wastewaters using a bismuth film screen-printed electrode assembly

Energy Technology Data Exchange (ETDEWEB)

Kadara, Rashid O.; Tothill, Ibtisam E. [Cranfield Biotechnology Centre, Cranfield University, MK45 4DT, Silsoe, Bedfordshire (United Kingdom)

2004-02-01

The key to remediative processes is the ability to measure toxic contaminants on-site using simple and cheap sensing devices, which are field-portable and can facilitate more rapid decision-making. A three-electrode configuration system has been fabricated using low-cost screen-printing (thick-film) technology and this coupled with a portable electrochemical instrument has provided a a relatively inexpensive on-site detector for trace levels of toxic metals. The carbon surface of the screen-printed working electrode is used as a substrate for in situ deposition of a metallic film of bismuth, which allows the electrochemical preconcentration of metal ions. Lead and cadmium were simultaneously detected using stripping chronopotentiometry at the bismuth film electrode. Detection limits of 8 and 10 ppb were obtained for cadmium(II) and lead(II), respectively, for a deposition time of 120 s. The developed method was applied to the determination of lead and cadmium in soils extracts and wastewaters obtained from polluted sites. For comparison purposes, a mercury film electrode and ICP-MS were also used for validation. (orig.)

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.

Development of a poly(alizarin red S)/ionic liquid film modified electrode for voltammetric determination of catechol

International Nuclear Information System (INIS)

Zhang, Qing; Pan, Dawei; Zhang, Haiyun; Han, Haitao; Kang, Qi

2014-01-01

Highlights: • This study is the first to conduct electroploymerization of ARS in RTILs. • BMIMBF 4 was successfully mixed in polymeric ARS film. • PARS/BMIMBF 4 film was tighter, smoother and better electrochemical property. • PARS/BMIMBF 4 /GCE showed superior performance for catechol determination. - Abstract: A novel modified electrode for voltammetric catechol determination was fabricated by electroploymerization of alizarin red S (ARS) onto a glassy carbon electrode (GCE) in one kind of room-temperature ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF 4 ). The polymeric ARS/ionic liquid (PARS/BMIMBF 4 ) film modified electrode was characterized by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and electrochemical methods. The EDX, XPS and FTIR results indicated that PARS/BMIMBF 4 film was successfully obtained. Compared with the GCE modified by electroploymerization of ARS in aqueous solution, the GCE modified by electroploymerization of ARS in BMIMBF 4 showed smoother and more compact morphology for coating and better electroanalytical properties. Given the combined electrochemical activity of PARS and excellent conductivity of BMIMBF 4 , the PARS/BMIMBF 4 /GCE has been successfully used for catechol determination by differential pulse voltammetry (DPV) with a linear range of 0.10 to 500 μM. The sensitivity and detection limit are 42 nA/μM and 0.026 μM, respectively. The PARS/BMIMBF 4 modified electrode was successfully applied to the determination of catechol in real water samples and may serve as a simple but high-performance sensor for the determination of some environmental pollutants

Pulsed-laser deposition and growth studies of Bi3Fe5O12 thin films

International Nuclear Information System (INIS)

Lux, Robert; Heinrich, Andreas; Leitenmeier, Stephan; Koerner, Timo; Herbort, Michael; Stritzker, Bernd

2006-01-01

Magneto-optical garnets are attractive because of their high Faraday rotation and low optical loss in the near infrared. Therefore their use is generally in nonreciprocal devices, i.e., as optical isolators in optical communication. In this paper we present data concerning the deposition of Bi 3 Fe 5 O 12 (BIG) thin films on (100) and (111) Gd 3 Ga 5 O 12 substrates using pulsed-laser deposition. Laser-induced processes on the surface of the oxide target used for ablation were analyzed and numerous films were deposited. We found the BIG film quality to be strongly affected by oxygen pressure, laser energy density, and the Bi/Fe film ratio, whereas temperature had a minor influence. We also investigated the BIG-film deposition using a target pressed from metallic Bi and Fe powders and found information on the growth behavior of BIG. We report on details of the film deposition and film properties determined by environmental scanning electron microscopy, energy dispersive x-ray analysis, Rutherford backscattering spectroscopy, and x-ray diffraction. In addition, we determined the Faraday rotation of the films

Preparation and Characterization of Nicke-iron Alloy Film as Freestanding Electrode for Oxygen Evolution Reaction

Directory of Open Access Journals (Sweden)

Yao Mengqi

2018-01-01

Full Text Available This work reports the porous nicke-iron alloy film supported on stainless steel mesh as freestanding electrode for enhanced oxygen evolution reaction (OER catalyst prepared from an one step electrodeposition method. Results indicated that the porous nickle-iron alloy film exhibits a low overpotential of 270 mV at 10 mA cm-2 and excellent electroconductibility. The superior OER properties can be attributed to its novel synthetic process, conductive substrate and porous structure. This work will provide a new strategy to fabricate alloy film for OER electrocatalyst.

Comparison of lead zirconate titanate thin films on ruthenium oxide and platinum electrodes

OpenAIRE

Bursill, Les A.; Reaney, Ian M.; Vijay, Dilip P.; Desu, Seshu B.

1994-01-01

High-resolution and bright- and dark-field transmission electron microscopy are used to characterize and compare the interface structures and microstructure of PZT/RuO2/SiO2/Si and PZT/Pt/Ti/SiO2/Si ferroelectric thin films, with a view to understanding the improved fatigue characteristics of PZT thin films with RuO2 electrodes. The RuO2/PZT interface consists of a curved pseudoperiodic minimal surface. The interface is chemically sharp with virtually no intermixing of RuO2 and PZT, as eviden...

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%).

Effect of an electrolyte salt dissolving in polysiloxane-based electrolyte on passive film formation on a graphite electrode

Science.gov (United States)

Nakahara, Hiroshi; Nutt, Steven

Electrochemical impedance spectroscopy (EIS) was performed during the first charge of a graphite/lithium metal test cell to determine the effect of an electrolyte salt on passive film formation in a polysiloxane-based electrolyte. The graphite electrode was separated from the lithium metal electrode by a porous polyethylene membrane immersed in a polysiloxane-based electrolyte with the dissolved lithium bis(oxalato) borate (LiBOB) or lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). In case of LiTFSI, the conductivity of system decreased at 1.2 V. In contrast, for the case of LiBOB, the conductivity decreased at 1.7 V. The magnitudes of charge transfer resistance and film resistance for LiTFSI were smaller than that for LiBOB. Passive films on highly oriented pyrolytic graphite (HOPG) after charging (lithiating) in polysiloxane-based electrolyte were inspected microscopically. Gel-like film and island-like films were observed for LiBOB [H. Nakahara, A. Masias, S.Y. Yoon, T. Koike, K. Takeya, Proceedings of the 41st Power Sources Conference, vol. 165, Philadelphia, June 14-17, 2004; H. Nakahara, S.Y. Yoon, T. Piao, S. Nutt, F. Mansfeld, J. Power Sources, in press; H. Nakahara, S.Y. Yoon, S. Nutt, J. Power Sources, in press]. However, for LiTFSI, there was sludge accumulation on the HOPG surface. Compositional analysis revealed the presence of silicon on both HOPG specimens with LiBOB and with LiTFSI. The electrolyte salt dissolved in the polysiloxane-based electrolyte changed the electrochemical and morphological nature of passive films on graphite electrode.

Electrochemical reactivity at graphitic micro-domains on polycrystalline boron doped diamond thin-films electrodes

International Nuclear Information System (INIS)

Mahe, E.; Devilliers, D.; Comninellis, Ch.

2005-01-01

This paper deals with the electrochemical reactivity of boron doped diamond (BDD) electrodes. A comparative study has been carried out to show the influence of the presence of graphitic micro-domains upon the surface of these films. Those graphitic domains are sometimes present on as-grown boron doped diamond electrodes. The effect of doping a pure Csp 3 diamond electrode is established by highly oriented pyrolytic graphite (HOPG) abrasion onto the diamond surface. In order to establish the effect of doping on a pure Csp 3 diamond electrode, the amount of graphitic domains was increased by means of HOPG crystals grafted onto the BDD surface. Indeed that method allows the enrichment of the Csp 2 contribution of the electrode. The presence of graphitic domains can be correlatively associated with the presence of kinetically active redox sites. The electrochemical reactivity of boron doped diamond electrodes shows a distribution of kinetic constants on the whole surface of the electrode corresponding to different active sites. In this paper, we have studied by cyclic voltammetry and electrochemical impedance spectroscopy the kinetics parameters of the ferri/ferrocyanide redox couple in KCl electrolyte. A method is proposed to diagnose the presence of graphitic domains on diamond electrodes, and an electrochemical 'pulse cleaning' procedure is proposed to remove them

LiFePO_4_−_xN_y thin-film electrodes coated on carbon fiber-modified current collectors for pseudocapacitors

International Nuclear Information System (INIS)

Chiu, Kuo-Feng; Su, Shih-Hsuan; Leu, Hoang-Jyh; Huang, Wei-Chieh

2015-01-01

LiFePO_4_−_xN_y thin films were sputter-deposited on micron carbon fibers (MCFs) under a gas mixture of N_2/Ar/H_2 as electrode materials in pseudocapacitors. The MCFs were fabricated by thermal chemical vapor deposition on stainless steel substrates as current collectors. Various amounts of N_2 were introduced by controlling the flow ratios of N_2 to Ar/H_2. The LiFePO_4_−_xN_y thin films coated on the surfaces of MCFs were observed by field emission scanning electron microscopy. The electrochemical properties of the LiFePO_4_−_xN_y thin films were characterized using cyclic voltammetry and charge–discharge processes. The LiFePO_4_−_xN_y thin-film electrode deposited under the optimal N_2 contents exhibited a high specific capacitance of 722 F/g at 1 A/g. Even at a current of 20 A/g, the electrode delivered a capacitance of 298 F/g. The pseudocapacitors using LiFePO_4_−_xN_y thin-film electrodes showed no significant capacitance fading after 1000 cycles at 1 A/g. The results indicated that nitrogen doping improved the electrochemical performances of LiFePO_4, demonstrating the potential of LiFePO_4_−_xN_y as an active material in pseudocapacitors. - Highlights: • LiFePO_4_−_xN_y thin films were sputter-deposited on micron carbon fibers (MCFs). • MCFs only act as a three-dimensional current collector in this system. • The pseudocapacitor exhibits a high specific capacitance.

Physical characterization of amorphous In-Ga-Zn-O thin-film transistors with direct-contact asymmetric graphene electrode

Directory of Open Access Journals (Sweden)

Jaewook Jeong

2014-09-01

Full Text Available High performance a-IGZO thin-film transistors (TFTs are fabricated using an asymmetric graphene drain electrode structure. A-IGZO TFTs (channel length = 3 μm were successfully demonstrated with a saturation field-effect mobility of 6.6 cm2/Vs without additional processes between the graphene and a-IGZO layer. The graphene/a-IGZO junction exhibits Schottky characteristics and the contact property is affected not only by the Schottky barrier but also by the parasitic resistance from the depletion region under the graphene electrode. Therefore, to utilize the graphene layer as S/D electrodes for a-IGZO TFTs, an asymmetric electrode is essential, which can be easily applied to the conventional pixel electrode structure.

Influence of aluminum nitride interlayers on crystal orientation and piezoelectric property of aluminum nitride thin films prepared on titanium electrodes

International Nuclear Information System (INIS)

Kamohara, Toshihiro; Akiyama, Morito; Ueno, Naohiro; Nonaka, Kazuhiro; Kuwano, Noriyuki

2007-01-01

Highly c-axis-oriented aluminum nitride (AlN) thin films have been prepared on titanium (Ti) bottom electrodes by using AlN interlayers. The AlN interlayers were deposited between Ti electrodes and silicon (Si) substrates, such as AlN/Ti/AlN/Si. The crystallinity and crystal orientation of the AlN films and Ti electrodes strongly depended on the thickness of the AlN interlayers. Although the sputtering conditions were the same, the X-ray diffraction intensity of AlN (0002) and Ti (0002) planes drastically increased, and the full-width at half-maximum (FWHM) of the X-ray rocking curves decreased from 5.1 o to 2.6 o and from 3.3 o to 2.0 o , respectively. Furthermore, the piezoelectric constant d 33 of the AlN films was significantly improved from - 0.2 to - 4.5 pC/N

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

Energy Technology Data Exchange (ETDEWEB)

Brewer, Steven J.; Bassiri-Gharb, Nazanin [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Deng, Carmen Z.; Callaway, Connor P. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Paul, McKinley K. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Woodward Academy, College Park, Georgia 30337 (United States); Fisher, Kenzie J. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Riverwood International Charter School, Atlanta, Georgia 30328 (United States); Guerrier, Jonathon E.; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Rudy, Ryan Q.; Polcawich, Ronald G. [Army Research Laboratory, Adelphi, Maryland 20783 (United States); Glaser, Evan R.; Cress, Cory D. [Naval Research Laboratory, Washington, DC 20375 (United States)

2016-07-14

The effects of gamma irradiation on the dielectric and piezoelectric responses of Pb[Zr{sub 0.52}Ti{sub 0.48}]O{sub 3} (PZT) thin film stacks were investigated for structures with conductive oxide (IrO{sub 2}) 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) {sup 60}Co gamma radiation. However, the low-field, relative dielectric permittivity, ε{sub r}, 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 (IrO{sub 2} electrodes).

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.

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

Energy Technology Data Exchange (ETDEWEB)

Pan Mingfei; Fang Guozhen; Liu Bing; Qian Kun [Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457 (China); Wang Shuo, E-mail: pmf2006@126.com [Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457 (China)

2011-04-01

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 (r{sup 2} = 0.9906). The limit of detection (S/N = 3) of the modified electrode was achieved to 1.34 x 10{sup -8} mol L{sup -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.

Stress and piezoelectric properties of aluminum nitride thin films deposited onto metal electrodes by pulsed direct current reactive sputtering

International Nuclear Information System (INIS)

Dubois, Marc-Alexandre; Muralt, Paul

2001-01-01

Polycrystalline aluminum nitride thin films were deposited onto platinum, aluminum, and titanium electrodes by reactive magnetron sputtering in the pulsed direct current mode. The films exhibited all a columnar microstructure and a c-axis texture. The built-in stress and the piezoelectric properties of these films were studied as a function of both the processing conditions and the electrode material. Stress was found to be very much dependent on the growth conditions, and values ranging from strong compression to high tension were observed. The piezoelectric d 33,f coefficient was shown to rely on substrate quality and ionic bombardment: The nucleation surface must be stable with regard to the nitrogen plasma and present a hexagonal symmetry and, on the other hand, enough energy must be delivered to the growing film through ionic bombardment. [copyright] 2001 American Institute of Physics

Improvement of High-Temperature Stability of Al2O3/Pt/ZnO/Al2O3 Film Electrode for SAW Devices by Using Al2O3 Barrier Layer

Directory of Open Access Journals (Sweden)

Xingpeng Liu

2017-12-01

Full Text Available In order to develop film electrodes for the surface acoustic wave (SAW devices operating in harsh high-temperature environments, novel Al2O3/Pt/ZnO/Al2O3 multilayered film electrodes were prepared by laser molecular beam epitaxy (LMBE at 150 °C. The first Al2O3 layer was used as a barrier layer to prevent the diffusion of Ga, La, and Si atoms from the La3Ga5SiO14 (LGS substrate to the film electrode and thus improved the crystalline quality of ZnO and Pt films. It was found that the resistance of the Al2O3/Pt/ZnO/Al2O3 electrode did not vary up to a temperature of 1150 °C, suggesting a high reliability of electrode under harsh high-temperature environments. The mechanism of the stable resistance of the Al2O3/Pt/ZnO/Al2O3 film electrodes at high temperature was investigated by analyzing its microstructure. The proposed Al2O3/Pt/ZnO/Al2O3 film electrode has great potential for application in high-temperature SAW devices.

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

Study of corrosion behavior of carbon steel under seawater film using the wire beam electrode method

International Nuclear Information System (INIS)

Liu, Zaijian; Wang, Wei; Wang, Jia; Peng, Xin; Wang, Yanhua; Zhang, Penghui; Wang, Haijie; Gao, Congjie

2014-01-01

Corrosion behavior of carbon steel under seawater film with various thickness was investigated by the wire beam electrode (WBE) method. It was found that the corrosion rate of carbon steel increased significantly under thin seawater film than it was immersed in seawater. The current variation under seawater film indicated that the thickness of diffusion layer of oxygen was about 500 μm, and the maximal current appeared around 40 μm, at which corrosion rate transited from cathodic control to anodic control. The results suggest that WBE method is helpful to study the corrosion process under thin electrolyte film

Free-standing 3D graphene/polyaniline composite film electrodes for high-performance supercapacitors

Science.gov (United States)

Wang, Shiyong; Ma, Li; Gan, Mengyu; Fu, Shenna; Dai, Wenqin; Zhou, Tao; Sun, Xiaowu; Wang, Huihui; Wang, Huining

2015-12-01

The research paper describes polyaniline (PANI) nanowires array on flexible polystyrene microsphere/reduced graphene (PS/rGN) film is synthesized by dilute polymerization, and then the PS microspheres are removed to form free-standing three-dimensional (3D) rGN/PANI composite film. The chemical and structural properties of the 3D rGN/PANI film are characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET), and the results confirm the 3D rGN/PANI film is synthesized successfully. When the film is used as a supercapacitor electrode, the maximum specific capacitance is as high as 740 F g-1 (or 581 F cm-3 for volumetric capacitance) at a current density of 0.5 A g-1 and the specific capacitance retains 87% of the initial after constant charge-discharge 1000 cycles at current density of 10 A g-1. It is believed that the free-standing 3D rGN/PANI film will have a great potential for application in supercapacitors.

Use of polished and mercury film-modified silver solid amalgam electrodes in electrochemical analysis of DNA

Czech Academy of Sciences Publication Activity Database

Fadrná, Renata; Cahová, Kateřina; Havran, Luděk; Josypčuk, Bohdan; Fojta, Miroslav

2005-01-01

Roč. 17, 5-6 (2005), s. 452-459 ISSN 1040-0397 R&D Projects: GA MPO 1H-PK/42; GA ČR GA203/04/1325; GA AV ČR KJB4004302 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z50040507 Keywords : DNA electrochemistry * solid amalgam electrodes * mercury film electrodes * DNA damage Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.189, year: 2005

Fluorination of Boron-Doped Diamond Film Electrodes for Minimization of Perchlorate Formation.

Science.gov (United States)

Gayen, Pralay; Chaplin, Brian P

2017-08-23

This research investigated the effects of surface fluorination on both rates of organic compound oxidation (phenol and terephthalic acid (TA)) and ClO 4 - formation at boron-doped diamond (BDD) film anodes at 22 °C. Different fluorination methods (i.e., electrochemical oxidation with perfluorooctanoic acid (PFOA), radio frequency plasma, and silanization) were used to incorporate fluorinated moieties on the BDD surface, which was confirmed by X-ray photoelectron spectroscopy (XPS). The silanization method was found to be the most effective fluorination method using a 1H,1H,2H,2H-perfluorodecyltrichlorosilane precursor to form a self-assembled monolayer (SAM) on the oxygenated BDD surface. The ClO 4 - formation decreased from rates of 0.45 ± 0.03 mmol m -2 min -1 during 1 mM NaClO 3 oxidation and 0.28 ± 0.01 mmol m -2 min -1 during 10 mM NaCl oxidation on the BDD electrode to below detectable levels (layer on the BDD surface that inhibited charge transfer via steric hindrance and hydrophobic effects. The surface coverages and thicknesses of the fluorinated films controlled the charge transfer rates, which was confirmed by estimates of film thicknesses using XPS and density functional theory simulations. The aliphatic silanized electrode also showed very high stability during OH • production. Perchlorate formation rates were below the detection limit (<0.12 μmoles m -2 min -1 ) for up to 10 consecutive NaClO 3 oxidation experiments.

(110)-Textured Ca-doped BiFeO_3 film on refined Pt(111) electrode layer on glass substrate at reduced temperature

International Nuclear Information System (INIS)

Chang, H.W.; Shen, C.Y.; Yuan, F.T.; Tien, S.H.; Lin, S.Y.; Chen, W.A.; Wang, C.R.; Tu, C.S.; Jen, S.U.

2016-01-01

Multiferroic and photovoltaic properties of polycrystalline Bi_0_._8_5Ca_0_._1_5FeO_3 (BCFO) film on refined Pt(111) electrode buffered glass substrate have been studied. Optimized Pt(111) electrode layer having large grain size and smooth morphology enables the development of highly (110)-textured BCFO film at a temperature as low as 450 °C. The prepared BCFO film has dense microstructure, fine grain size, and smooth surface morphology. Good ferroelectric properties with the remanent polarization (2P_r) of 108 μC/cm"2 and electrical coercive field of 405 kV/cm are achieved. Improved ferromagnetic properties with magnetization of 9.2 emu/cm"3 and coercivity of 1250 Oe are also attained. Significant PV properties with open-circuit photovoltage of 0.49 V and the short-circuit photocurrent of 67.4 μA/cm"2 at illumination intensity of 228 mW/cm"2 are observed, which are comparable to BCFO ceramics or BFO epitaxial films. - Highlights: • BCFO polycrystalline film with (110) texture is formed on Pt(111) electrode. • Pt(111) underlayer induces BCFO(110) film with fine grain and flat surface. • Good multiferroic and photovoltaic properties are achieved simultaneously. • Improved multiferroic and photovoltaic properties makes BCFO film a multifunctional material for advanced applications.

Solid-state electrochemiluminescence sensor through the electrodeposition of Ru(bpy)32+/AuNPs/chitosan composite film onto electrode

International Nuclear Information System (INIS)

Yun Wen; Xu Ying; Dong Ping; Ma Xiongxiong; He Pingang; Fang Yuzhi

2009-01-01

Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+ ) has been successfully immobilized onto electrode through the electrodeposition of Ru(bpy) 3 2+ /AuNPs/chitosan composite film. In the experiments, chitosan solution was first mixed with Au nanoparticles (AuNPs) and Ru(bpy) 3 2+ . Then, during chronopotentiometry experiments in this mixed solution, a porous 3D network structured film containing Ru(bpy) 3 2+ , AuNPs and chitosan has been electrodeposited onto cathode due to the deposition of chitosan when pH value is over its pK a (6.3). The applied current density is crucial to the film thickness and the amount of the entrapped Ru(bpy) 3 2+ . Additionally, these doping Ru(bpy) 3 2+ in the composite film maintained their intrinsic electrochemical and electrochemiluminescence activities. Consequently, this Ru(bpy) 3 2+ /AuNPs/chitosan modified electrode has been used in ECL to detect tripropylamine, and the detection limit was 5 x 10 -10 M

Investigations of magnetoelectric behavior in BiFe0.95Co0.05O3 nanoparticles

Science.gov (United States)

Shrimali, V. G.; Gadani, Keval; Rathod, K. N.; Boricha, Hetal; Prajapati, Pooja; Keshvani, M. J.; Kataria, B. R.; Joshi, A. D.; Pandya, D. D.; Shah, N. A.; Solanki, P. S.

2017-05-01

Nanophasic BiFe0.95Co0.05O3 (BFCO) particles were synthesized using low cost, easy, simple, environment friendly and low temperature acetate precursor based modified sol-gel method. Influence of particle size and magnetic field on the structural, dielectric, impedance and a.c. conductivity of BFCO is investigated. X-ray diffraction (XRD) measurement has been performed to understand the structural modifications in the samples upon increasing the sintering temperature. Crystallite size (CS) increases from 33.62nm to 39.56nm due to agglomeration effect between the smaller crystallites. Effect of sintering temperature on the dielectric, impedance and conductivity has been studied and understood in the context of the creation of crystallite (particle) size and oxygen vacancies created due to high temperature sintering process. Magnetic field induced modifications in all these electrical properties [magnetoelectric (ME) effects] for the presently studied BFCO samples have been discussed on the basis of magnetostriction effect and charge mobility across the Fe-O lattice in the samples.

Transparent ambipolar organic thin film transistors based on multilayer transparent source-drain electrodes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Nan; Hu, Yongsheng, E-mail: huyongsheng@ciomp.ac.cn, E-mail: liuxy@ciomp.ac.cn; Lin, Jie; Li, Yantao; Liu, Xingyuan, E-mail: huyongsheng@ciomp.ac.cn, E-mail: liuxy@ciomp.ac.cn [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

2016-08-08

A fabrication method for transparent ambipolar organic thin film transistors with transparent Sb{sub 2}O{sub 3}/Ag/Sb{sub 2}O{sub 3} (SAS) source and drain electrodes has been developed. A pentacene/N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic di-imide (PTCDI-C13) bilayer heterojunction is used as the active semiconductor. The electrodes are deposited by room temperature electron beam evaporation. The devices are fabricated without damaging the active layers. The SAS electrodes have high transmittance (82.5%) and low sheet resistance (8 Ω/sq). High performance devices with hole and electron mobilities of 0.3 cm{sup 2}/V s and 0.027 cm{sup 2}/V s, respectively, and average visible range transmittance of 72% were obtained. These transistors have potential for transparent logic integrated circuit applications.

Transparent and flexible electrodes and supercapacitors using polyaniline/single-walled carbon nanotube composite thin films

Science.gov (United States)

Ge, Jun; Cheng, Guanghui; Chen, Liwei

2011-08-01

Large-scale transparent and flexible electronic devices have been pursued for potential applications such as those in touch sensors and display technologies. These applications require that the power source of these devices must also comply with transparent and flexible features. Here we present transparent and flexible supercapacitors assembled from polyaniline (PANI)/single-walled carbon nanotube (SWNT) composite thin film electrodes. The ultrathin, optically homogeneous and transparent, electrically conducting films of the PANI/SWNT composite show a large specific capacitance due to combined double-layer capacitance and pseudo-capacitance mechanisms. A supercapacitor assembled using electrodes with a SWNT density of 10.0 µg cm-2 and 59 wt% PANI gives a specific capacitance of 55.0 F g-1 at a current density of 2.6 A g-1, showing its possibility for transparent and flexible energy storage.

Deactivation of nickel hydroxide-gold modified electrodes

OpenAIRE

Caram, Bruno; Tucceri, Ricardo

2013-01-01

The aim of the present work was to study how the charge-transport process of a nickel hydroxide film electrochemically synthesized on a gold substrate is modified when the electrode is stored for a long time. It was found that nickel hydroxide films are deactivated under storage, that is, films became less conductive than films immediately prepared (nondeactivated). This study was carried out in the context of the rotating disc electrode voltammetry when the modified electrode contacts an ele...

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

Electrochemical reactivity at graphitic micro-domains on polycrystalline boron doped diamond thin-films electrodes

Energy Technology Data Exchange (ETDEWEB)

Mahe, E. [LI2C CNRS/UMR 7612, Laboratoire d' Electrochimie, Universite Pierre-et-Marie Curie - case courrier 51, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Devilliers, D. [LI2C CNRS/UMR 7612, Laboratoire d' Electrochimie, Universite Pierre-et-Marie Curie - case courrier 51, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Comninellis, Ch. [Unite de Genie Electrochimique, Institut de sciences des procedes chimiques et biologiques, Ecole Polytechnique Federale de Lausanne, 1015, Lausanne (Switzerland)

2005-04-01

This paper deals with the electrochemical reactivity of boron doped diamond (BDD) electrodes. A comparative study has been carried out to show the influence of the presence of graphitic micro-domains upon the surface of these films. Those graphitic domains are sometimes present on as-grown boron doped diamond electrodes. The effect of doping a pure Csp{sup 3} diamond electrode is established by highly oriented pyrolytic graphite (HOPG) abrasion onto the diamond surface. In order to establish the effect of doping on a pure Csp{sup 3} diamond electrode, the amount of graphitic domains was increased by means of HOPG crystals grafted onto the BDD surface. Indeed that method allows the enrichment of the Csp{sup 2} contribution of the electrode. The presence of graphitic domains can be correlatively associated with the presence of kinetically active redox sites. The electrochemical reactivity of boron doped diamond electrodes shows a distribution of kinetic constants on the whole surface of the electrode corresponding to different active sites. In this paper, we have studied by cyclic voltammetry and electrochemical impedance spectroscopy the kinetics parameters of the ferri/ferrocyanide redox couple in KCl electrolyte. A method is proposed to diagnose the presence of graphitic domains on diamond electrodes, and an electrochemical 'pulse cleaning' procedure is proposed to remove them.

Electrocatalytic reduction of oxygen at glassy carbon electrode modified by polypyrrole/anthraquinones composite film in various pH media

International Nuclear Information System (INIS)

Valarselvan, S.; Manisankar, P.

2011-01-01

Graphical abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . Highlights: → Hydroxyl derivatives of anthraquinones as electrocatalysts for dioxygen reduction. → AQ/PPy composite film on GC electrode exhibits potent electrocatalytic activity. → Substituent groups influence electrocatalytic dioxygen reduction. → Surface coverage varies the rate of electrocatalytic dioxygen reduction. - Abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. The electrochemical behaviour of the modified electrodes was examined in various pH media and both the formal potential of anthraquinones and reduction potential of dioxygen exhibited pH dependence. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . pH 6.0 was chosen as the most suitable medium to study the electrocatalysis by comparing the peak potential of oxygen reduction and enhancement in peak current for oxygen reduction. The diffusion coefficient values of AQ at the modified electrodes and the number of electrons involved in AQ reduction were evaluated by chronoamperometric and chronocoulometric techniques, respectively. In addition, hydrodynamic voltammetric studies showed the involvement of two electrons in O 2 reduction. The mass specific activity of AQ used, the diffusion coefficient of oxygen and the heterogeneous rate constants for the oxygen reduction at the surface of modified electrodes were also determined by rotating disk voltammetry.

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...

Pt-graphene electrodes for dye-sensitized solar cells

International Nuclear Information System (INIS)

Hoshi, Hajime; Tanaka, Shumpei; Miyoshi, Takashi

2014-01-01

Highlights: • Graphene films with Pt nanoparticles were prepared from commercial graphene. • Pt consumption can be reduced by using Pt-graphene films. • The film showed improved catalytic activity for the reaction I 3 − /I − . • The film can be used as the counter electrode of dye-sensitized solar cells (DSSCs). • The performance of DSSC was superior to that of the Pt electrode. - Abstract: A simple paste method for fabricating graphene films with Pt nanoparticles was developed. First, graphene pastes with Pt nanoparticles were prepared from commercially available graphene. The resulting films of graphene nanoplatelet aggregates with Pt nanoparticles (Pt-GNA) contained Pt nanoparticles distributed over the entire three-dimensional surface of the GNA. Then, the catalytic activity for the I 3 − /I − redox reaction was evaluated by cyclic voltammetry. The GNA electrode exhibited higher activity than a graphene nanoplatelet electrode because of its higher effective surface area. Addition of Pt nanoparticles to the electrodes improved the catalytic activity. In particular, a large Faradaic current for the I 3 − /I − reaction was observed for the Pt-GNA electrode. As the counter electrodes of dye-sensitized solar cells (DSSCs), their performance was consistent with the cyclic voltammetry results. In particular, the DSSC performance of the Pt-GNA electrode was superior to that of the Pt electrodes commonly used in DSSCs

Free-standing, flexible β-Ni(OH)2/electrochemically-exfoliated graphene film electrode for efficient oxygen evolution

Science.gov (United States)

Wang, Lanlan; Zhang, Jian; Jiang, Weitao; Zhao, Hong; Liu, Hongzhong

2018-03-01

The oxidation of water into molecular oxygen (oxygen evolution reaction, OER) is a pivotal reaction in many energy conversion devices. The high cost of IrO2, however, seriously hinder its large-scale applications in water oxidation. Here, we have at first reported a free-standing and flexible film electrode consisting of 2D β-Ni(OH)2/electrochemically-exfoliated graphene hybrid nanosheets (NiG-2), which is synthesized by a solvothermal reaction and an assembly process. The as-obtained NiG-2 film electrode exhibited an excellent electrocatalytic OER activity with an extremely low OER onset overpotential of ∼250 mV in a 1 M KOH aqueous solution, which is lower than these of the commercial Ir/C (370 mV at 10 mA cm-2) catalyst.

N-Doped graphene/PEDOT composite films as counter electrodes in DSSCs: Unveiling the mechanism of electrocatalytic activity enhancement

Science.gov (United States)

Paterakis, Georgios; Raptis, Dimitrios; Ploumistos, Alexandros; Belekoukia, Meltiani; Sygellou, Lamprini; Ramasamy, Madeshwaran Sekkarapatti; Lianos, Panagiotis; Tasis, Dimitrios

2017-11-01

A composite film was obtained by layer deposition of N-doped graphene and poly(3,4-ethylenedioxythiophene) (PEDOT) and was used as Pt-free counter electrode for dye-sensitized solar cells. N-doping of graphene was achieved by annealing mixtures of graphene oxide with urea. Various parameters concerning the treatment of graphene oxide-urea mixtures were monitored in order to optimize the electrocatalytic activity in the final solar cell device. These include the mass ratio of components, the annealing temperature, the starting concentration of the mixture in aqueous solution and the spinning rate for film formation. PEDOT was applied by electrodeposition. The homogeneity of PEDOT coverage onto either untreated or thermally annealed graphene oxide-urea film was assessed by imaging (AFM/SEM) and surface techniques (XPS). It was found that PEDOT was deposited in the form of island structures onto untreated graphene oxide-urea film. On the contrary, the annealed film was homogeneously covered by the polymer, acquiring morphology of decreased roughness. An apparent chemical interaction between PEDOT and N-doped graphene flakes was revealed by XPS data, involving potential grafting of PEDOT chains onto graphitic lattice through Csbnd C bonding. In addition, diffusion of nitrogen-containing fragments within the PEDOT layer was found to take place during electrodeposition process, resulting in enhanced interfacial interactions between components. The solar cell with the optimized N-doped graphene/PEDOT composite counter electrode exhibited a power conversion efficiency (η) of 7.1%, comparable within experimental error to that obtained by using a reference Pt counter electrode, which showed a value of 7.0%.

Fabrication of Polymer Microneedle Electrodes Coated with Nanoporous Parylene

Science.gov (United States)

Nishinaka, Yuya; Jun, Rina; Setia Prihandana, Gunawan; Miki, Norihisa

2013-06-01

In this study, we demonstrate the fabrication of polymer microneedle electrodes covered with a nanoporous parylene film that can serve as flexible electrodes for a brain-machine interface. In brain wave measurement, the electric impedance of electrodes should be below 10 kΩ at 15 Hz, and the conductive layer needs to be protected to survive its insertion into the stratum corneum. Polymer microneedles can be used as substrates for flexible electrodes, which can compensate for the movement of the skin; however, the adhesion between a conductive metal film, such as a silver film, and a polymer, such as poly(dimethylsiloxane) (PDMS), is weak. Therefore, we coated the electrode surface with a nanoporous parylene film, following the vapor deposition of a silver film. When the porosity of the parylene film is appropriate, it protects the silver film while allowing the electrode to have sufficient conductivity. The porosity can be controlled by adjusting the amount of the parylene dimer used for the deposition or the parylene film thickness. We experimentally verified that a conductive membrane was successfully protected while maintaining a conductivity below 10 kΩ when the thickness of the parylene film was between 25 and 38 nm.

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.

Electrografting of N’,N’-dimethylphenothiazin-5-ium-3,7-diamine (Azure A) diazonium salt forming electrocatalytic organic films on gold or graphene oxide gold hybrid electrodes

International Nuclear Information System (INIS)

Gómez-Anquela, C.; Revenga-Parra, M.; Abad, J.M.; Marín, A. García; Pau, J.L.; Pariente, F.; Piqueras, J.; Lorenzo, E.

2014-01-01

Electroactive films containing redox active phenothiazine moieties are covalently bound onto gold and graphene oxide gold hybrid electrodes, using reductive redox grafting of N’,N’-dimethylphenothiazin-5-ium-3,7-diamine (Azure A) diazonium salt. The grafting procedure is based on continuous voltammetric potential sweep of solutions containing the phenothiazine diazonium salt previously generated in situ. Control of the film thickness, electroactivity and stability can easily be exerted through appropriate choice of the concentration and number of potential scans performed. Cyclic Voltammetry, Electrochemical Quartz Crystal Microbalance (EQCM) and Spectroscopic Ellipsometry are used to characterize the growth process as well as the viscoelastic properties of the resulting stable electrografted films. The electron transfer reactions through the films are mediated by the presence of the Azure A redox moieties, which show a quasi-reversible electrochemical response and exhibit a potent electrocatalytic effect toward the oxidation of NADH. This electrocatalytic model has been used to compare the properties of Azure A electrografted films generated on gold electrodes with those obtained on hybrid electrodes composed by graphene oxide modified gold electrodes

Effect of pore structure on anomalous behaviour of the lithium intercalation into porous V2O5 film electrode using fractal geometry concept

International Nuclear Information System (INIS)

Jung, Kyu-Nam; Pyun, Su-Il

2006-01-01

The effect of pore structure on anomalous behaviour of the lithium intercalation into porous V 2 O 5 film electrode has been investigated in terms of fractal geometry by employing ac-impedance spectroscopy combined with N 2 gas adsorption method and atomic force microscopy (AFM). For this purpose, porous V 2 O 5 film electrodes with different pore structures were prepared by the polymer surfactant templating method. From the analysis of N 2 gas adsorption isotherms and the triangulation analysis of AFM images, it was found that porous V 2 O 5 surfaces exhibited self-similar scaling properties with different fractal dimensions depending upon amount of the polymer surfactant in solution and the spatial cut-off ranges. All the ac-impedance spectra measured on porous V 2 O 5 film electrodes showed the non-ideal behaviour of the charge-transfer reaction and the diffusion reaction, which resulted from the interfacial capacitance dispersion and the frequency dispersion of the diffusion impedance, respectively. From the comparison between the surface fractal dimensions by using N 2 gas adsorption method and AFM, and the analysis of ac-impedance spectra by employing a constant phase element (CPE), it is experimentally confirmed that the lithium intercalation into porous V 2 O 5 film electrode is crucially influenced by the pore surface irregularity and the film surface irregularity

Pt-graphene electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Hoshi, Hajime, E-mail: hoshi@ed.tus.ac.jp; Tanaka, Shumpei; Miyoshi, Takashi

2014-12-15

Highlights: • Graphene films with Pt nanoparticles were prepared from commercial graphene. • Pt consumption can be reduced by using Pt-graphene films. • The film showed improved catalytic activity for the reaction I{sub 3}{sup −}/I{sup −}. • The film can be used as the counter electrode of dye-sensitized solar cells (DSSCs). • The performance of DSSC was superior to that of the Pt electrode. - Abstract: A simple paste method for fabricating graphene films with Pt nanoparticles was developed. First, graphene pastes with Pt nanoparticles were prepared from commercially available graphene. The resulting films of graphene nanoplatelet aggregates with Pt nanoparticles (Pt-GNA) contained Pt nanoparticles distributed over the entire three-dimensional surface of the GNA. Then, the catalytic activity for the I{sub 3}{sup −}/I{sup −} redox reaction was evaluated by cyclic voltammetry. The GNA electrode exhibited higher activity than a graphene nanoplatelet electrode because of its higher effective surface area. Addition of Pt nanoparticles to the electrodes improved the catalytic activity. In particular, a large Faradaic current for the I{sub 3}{sup −}/I{sup −} reaction was observed for the Pt-GNA electrode. As the counter electrodes of dye-sensitized solar cells (DSSCs), their performance was consistent with the cyclic voltammetry results. In particular, the DSSC performance of the Pt-GNA electrode was superior to that of the Pt electrodes commonly used in DSSCs.

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)

Wang, Zhiqiang; Wang, Hui; Zhang, Zhihao; Yang, Xiaojing; Liu, Gang

2014-01-01

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

Printed optically transparent graphene cellulose electrodes

Science.gov (United States)

Sinar, Dogan; Knopf, George K.; Nikumb, Suwas; Andrushchenko, Anatoly

2016-02-01

Optically transparent electrodes are a key component in variety of products including bioelectronics, touch screens, flexible displays, low emissivity windows, and photovoltaic cells. Although highly conductive indium tin oxide (ITO) films are often used in these electrode applications, the raw material is very expensive and the electrodes often fracture when mechanically stressed. An alternative low-cost material for inkjet printing transparent electrodes on glass and flexible polymer substrates is described in this paper. The water based ink is created by using a hydrophilic cellulose derivative, carboxymethyl cellulose (CMC), to help suspend the naturally hydrophobic graphene (G) sheets in a solvent composed of 70% DI water and 30% 2-butoxyethanol. The CMC chain has hydrophobic and hydrophilic functional sites which allow adsorption on G sheets and, therefore, permit the graphene to be stabilized in water by electrostatic and steric forces. Once deposited on the functionalized substrate the electrical conductivity of the printed films can be "tuned" by decomposing the cellulose stabilizer using thermal reduction. The entire electrode can be thermally reduced in an oven or portions of the electrode thermally modified using a laser annealing process. The thermal process can reduce the sheet resistance of G-CMC films to < 100 Ω/sq. Experimental studies show that the optical transmittance and sheet resistance of the G-CMC conductive electrode is a dependent on the film thickness (ie. superimposed printed layers). The printed electrodes have also been doped with AuCl3 to increase electrical conductivity without significantly increasing film thickness and, thereby, maintain high optical transparency.

Ion transport and phase transformation in thin film intercalation electrodes

Energy Technology Data Exchange (ETDEWEB)

Wunde, Fabian; Nowak, Susann; Muerter, Juliane; Hadjixenophontos, Efi; Berkemeier, Frank; Schmitz, Guido [Stuttgart Univ. (Germany). Inst. fuer Materialwissenschaft

2017-11-15

Thin film battery electrodes of the olivine structure LiFePO{sub 4} and the spinel phase LiMn{sub 2}O{sub 4} are deposited through ion-beam sputtering. The intercalation kinetics is studied by cyclo-voltammetry using variation of the cycling rate over 4 to 5 orders of magnitude. The well-defined layer geometry allows a detailed quantitative analysis. It is shown that LiFePO{sub 4} clearly undergoes phase separation during intercalation, although the material is nano-confined and very high charging rates are applied. We present a modified Randles-Sevcik evaluation adapted to phase-separating systems. Both the charging current and the overpotential depend on the film thickness in a systematic way. The analysis yields evidence that the grain boundaries are important short circuit paths for fast transport. They increase the electrochemical active area with increasing layer thickness. Evidence is obtained that the grain boundaries in LiFePO{sub 4} have the character of an ion-conductor of vanishing electronic conductivity.

Nanostructured Cu2O thin film electrodes prepared by electrodeposition for rechargeable lithium batteries

International Nuclear Information System (INIS)

Bijani, S.; Gabas, M.; Martinez, L.; Ramos-Barrado, J.R.; Morales, J.; Sanchez, L.

2007-01-01

Uniform films of Cu 2 O with thickness below 1 μm were prepared from a Cu(II) lactate solution. The deposits were compact and of high purity with the particle size varying from 60 to 400 nm. They were tested as electrodes in lithium batteries and their electrochemical response was consistent with the Cu 2 O + 2e - + 2Li + ↔ 2Cu + Li 2 O reaction. Nevertheless, the reversibility of this reaction was dependent on thickness. Kinetic factors associated with the poor electronic conductivity of Cu 2 O could account for the relevance of the influence of film thickness. The thinnest film, about 300 nm thick, exhibited the best electrochemical performance by sustaining a specific capacity as high as 350 Ah kg -1

Characteristics of RuO{sub 2}-SnO{sub 2} nanocrystalline-embedded amorphous electrode for thin film microsupercapacitors

Energy Technology Data Exchange (ETDEWEB)

Kim, Han-Ki [Core Technology Laboratory, Samsung SDI, 575 Shin-dong, Youngtong-Gu, Suwon, Gyeonggi-Do 442-391 (Korea, Republic of)]. E-mail: hanki1031.kim@samsung.com; Choi, Sun-Hee [Nano Materials Research Center, Korea Institute of Science and Technology (KIST), PO Box 131 Choengryang, Seoul 130-650 (Korea, Republic of); Yoon, Young Soo [Department of Advanced Fusion Technology (DAFT), Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Chang, Sung-Yong [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Kwangju 500-712 (Korea, Republic of); Ok, Young-Woo [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Kwangju 500-712 (Korea, Republic of); Seong, Tae-Yeon [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Kwangju 500-712 (Korea, Republic of)

2005-03-22

The characteristics of RuO{sub 2}-SnO{sub 2} nanocrystalline-embedded amorphous electrode, grown by DC reactive sputtering, was investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM), and transmission electron diffraction (TED) examination results showed that Sn and Ru metal cosputtered electrode in O{sub 2}/Ar ambient have RuO{sub 2}-SnO{sub 2} nanocrystallines in an amorphous oxide matrix. It is shown that the cyclic voltammorgram (CV) result of the RuO{sub 2}-SnO{sub 2} nanocrystalline-embedded amorphous film in 0.5 M H{sub 2}SO{sub 4} liquid electrolyte is similar to a bulk-type supercapacitor behavior with a specific capacitance of 62.2 mF/cm{sup 2} {mu}m. This suggests that the RuO{sub 2}-SnO{sub 2} nanocrystalline-embedded amorphous film can be employed in hybrid all-solid state energy storage devises as an electrode of supercapacitor.

Enhanced Cyclability of Lithium-Oxygen Batteries with Electrodes Protected by Surface Films Induced via In-Situ Electrochemical Process

Energy Technology Data Exchange (ETDEWEB)

Liu, Bin; Xu, Wu; Tao, Jinhui; Yan, Pengfei; Zheng, Jianming; Engelhard, Mark H.; Lu, Dongping; Wang, Chongmin; Zhang, Jiguang

2018-04-16

Although the rechargeable lithium-oxygen (Li-O2) batteries have extremely high theoretical specific energy, the practical application of these batteries is still limited by the instability of their carbon-based air-electrode, Li metal anode, and electrolytes towards reduced oxygen species. Here we demonstrate a simple one-step in-situ electrochemical pre-charging strategy to generate thin protective films on both carbon nanotubes (CNTs) air-electrode and Li metal anode simultaneously under an inert atmosphere. Li-O2 cells after such pre-treatment demonstrate significantly extended cycle life of 110 and 180 cycles under the capacity-limited protocol of 1000 mAh g-1 and 500 mAh g-1, respectively, which is far more than those without pre-treatment. The thin-films formed from decomposition of electrolyte during in-situ electrochemical pre-charging process in an inert environment can protect both CNTs air-electrode and Li metal anode prior to conventional Li-O2 discharge/charge cycling where reactive reduced oxygen species are formed. This work provides a new approach for protections of carbon-based air-electrode and Li metal anode in practical Li-O2 batteries, and may also be applied to other battery systems.

Nitric Oxide Detection with Glassy Carbon Electrodes Coated with Charge-different Polymer Films

Directory of Open Access Journals (Sweden)

Jianping Lei

2005-04-01

Full Text Available Trace amounts of nitric oxide (NO have been determined in aqueous phosphate buffersolutions (pH=7.4 by using a glassy carbon electrode coated with three charge-different polymerfilms. The glassy carbon electrode was coated first with negatively charged Nafion film containingtetrakis(pentafluorophenylporphyrin iron(III chloride (Fe(IIITPFPP as the NO oxidation catalyst,and then with positively charged poly(acrylamide-co-diallyldimethylammonium chloride (PADDAand with neutral poly(dimethylsiloxane (silicone at the outermost layer. This polymer-coatedelectrode showed an excellent selectivity towards NO against possible concomitants in blood such asnitrite, ascorbic acid, uric acid, and dopamine. All current ratios between each concomitant and NOat the cyclic voltammogram was in 10-3 ~ 10-4. This type of electrode showed a detection limit of80 nM for NO. It was speculated from the electrochemical study in methanol that high-valent oxoiron(IV of Fe(TPFPP participated in the catalytic oxidation of NO.

Electrocatalytic oxidation of ascorbic acid by [Fe(CN){sub 6}]{sup 3-/4-} redox couple electrostatically trapped in cationic N,N-dimethylaniline polymer film electropolymerized on diamond electrode

Energy Technology Data Exchange (ETDEWEB)

Roy, Protiva Rani [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Saha, Madhu Sudan [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Okajima, Takeyoshi [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Ohsaka, Takeo [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Mail Box G1-5, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)]. E-mail: ohsaka@echem.titech.ac.jp

2006-06-01

Multinegatively charged metal complex, hexacyanoferrate ([Fe(CN){sub 6}]{sup 4-}), was electrostatically trapped in the cationic polymer film of N,N-dimethylaniline (PDMA) which was electrochemically deposited on the boron-doped diamond (BDD) electrode by controlled-potential electro-oxidation of the monomer. This ferrocyanide-trapped PDMA film was used to catalyze the oxidation of ascorbic acid (AA). Increase in the oxidation current response with a negative shift of the anodic peak potential was observed at the cationic PDMA film-coated BDD (PDMA|BDD) electrode, compared with that at the bare BDD electrode. A more drastic enhancement in the oxidation peak current as well as more negative shift of oxidation potential was found at the ferrocyanide-trapped PDMA film-coated BDD ([Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD) electrode. This [Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD electrode can be used as an amperometric sensor of AA. Ferrocyanide, electrostatically trapped in the polymer film shows more electrocatalytic activity than that coordinatively attached to the polymer film or dissolved in the solution phase. The electrocatalytic current depends on the surface coverage of ferricyanide, {gamma} {sub Fe}, within the polymer film. Diffusion coefficient (D) of AA in the solution was estimated by rotating disk electrode voltammetry: D = (5.8 {+-} 0.3) x 10{sup -6} cm{sup 2} s{sup -1}. The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0 x 10{sup 4} M{sup -1} s{sup -1}. In the hydrodynamic amperometry using the [Fe(CN){sub 6}]{sup 3-/4-}|PDMA|BDD electrode, a successive addition of 1 {mu}M AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233 {mu}A cm{sup -2} {mu}M{sup -1}.

Preparation and Properties of Mercury Film Electrodes on Solid Amalgam Surface

Czech Academy of Sciences Publication Activity Database

Josypčuk, Bohdan; Fojta, Miroslav; Barek, J.

2010-01-01

Roč. 22, 17-18 (2010), s. 1967-1973 ISSN 1040-0397. [International Conference on Modern Electroanalytical Methods. Prague, 09.12.2009-14.12.2009] R&D Projects: GA ČR GA203/07/1195; GA AV ČR IAA400400806; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : voltammetry * solid and paste amalgam * Mercury film electrode Subject RIV: CG - Electrochemistry Impact factor: 2.721, year: 2010

Modification of Patterned Nanoporous Gold Thin Film Electrodes via Electro-annealing and Electrochemical Etching

Science.gov (United States)

Dorofeeva, Tatiana

Nanostructured materials have had a major impact on various fields, including medicine, catalysis, and energy storage, for the major part due to unique phenomena that arise at nanoscale. For this reason, there is a sustained need for new nanostructured materials, techniques to pattern them, and methods to precisely control their nanostructure. To that end, the primary focus of this dissertation is to demonstrate novel techniques to fabricate and tailor the morphology of a class of nanoporous metals, obtained by a process known as dealloying. In this process, while the less noble constituent of an alloy is chemically dissolved, surface-diffusion of the more noble constituent leads to self-assembly of a bicontinuous ligament network with characteristic porosity of ˜70% and ligament diameter of 10s of nanometers. As a model material produced by dealloying, this work employ nanoporous gold (np-Au), which has attracted significant attention of desirable features, such as high effective surface area, electrical conductivity, well-defined thiol-based surface modification strategies, microfabrication-compatibility, and biocompatibility. The most commonly method used to modify the morphology of np-Au is thermal treatment, where the enhanced diffusivity of the surface atoms leads to ligament (and consequently pore) coarsening. This method, however, is not conducive to modifying the morphology of thin films at specific locations on the film, which is necessary for creating devices that may need to contain different morphologies on a single device. In addition, coarsening attained by thermal treatment also leads to an undesirable reduction in effective surface area. In response to these challenges, this work demonstrates two different techniques that enables in situ modification of np-Au thin film electrodes obtained by sputter-deposition of a precursors silver-rich gold-silver alloy. The first method, referred to as electro-annealing, is achieved by injecting electrical

Improving electrochemical performance of flexible thin film electrodes with micropillar array structures

International Nuclear Information System (INIS)

Myllymaa, Sami; Myllymaa, Katja; Lappalainen, Reijo; Pirinen, Sami; Pakkanen, Tapani A; Pakkanen, Tuula T; Suvanto, Mika

2012-01-01

For reliable function, bioelectrodes require a stable, low-impedance contact with the target tissue. In biosignal monitoring applications, in which low ion current densities are recorded, it is important to minimize electrode contact impedances. Recently, several flexible electrode concepts have been introduced for single-patient use. These electrodes conform well on the patient skin enabling an artifact-free, low-noise recording. In this study, polydimethylsiloxane (PDMS) elastomer was used as an electrode substrate material. One half of the substrates were surface-patterned with micropillars produced by using micro-working robot-made mold inserts and a replica molding technique. The substrates were subsequently coated with thin films of titanium (Ti), copper (Cu), silver (Ag) or silver–silver chloride (Ag/AgCl). Electrical impedance spectroscopy studies revealed that the micropillar structure caused statistically significant reductions in impedance modulus and phase for each coating candidate. The relative effect was strongest for pure Ag, for which the values of the real part (Z′) and the imaginary part (Z″) decreased to less than one tenth of the original (smooth) values. However, Ag/AgCl, as expected, proved to be a superior electrode material. Coating with chloride drastically reduced the interfacial impedance compared to pure Ag. Further significant reduction was achieved by the micropillars, since the phase angle declined from 10–13° (for smooth samples, f < 50 Hz) to a value as low as 5°. Equivalent circuit modeling was used to obtain a better understanding of phenomena occurring at various electrode–electrolyte interfaces. The knowledge obtained in this study will be exploited in the further development of flexible electrodes and miniaturized biointerfaces with improved electrochemical characteristics. (paper)

Electrochemical dissolution of fresh and passivated chalcopyrite electrodes. Effect of pyrite on the reduction of Fe3+ ions and transport processes within the passive film

International Nuclear Information System (INIS)

Olvera, O.G.; Quiroz, L.; Dixon, D.G.; Asselin, E.

2014-01-01

Graphical abstract: - Highlights: • FeS 2 increased the dissolution rate of fresh and passivated CuFeS 2 electrodes. • Fe 3+ reduction was the rate controlling step in the dissolution of fresh CuFeS 2 . • Diffusion within the passive film controlled the dissolution rate of passivated CuFeS 2 . - Abstract: The effect of pyrite (FeS 2 ) on the electrochemical dissolution of fresh and passivated chalcopyrite (CuFeS 2 ) electrodes has been studied. Current density values for the dissolution of CuFeS 2 were calculated from EIS measurements. FeS 2 increased the dissolution rate of fresh and passivated CuFeS 2 electrodes indicating that the galvanic effect continued even after the electrode was chemically passivated. The dissolution rate of CuFeS 2 decreased by a factor of 3 after the passivation treatment. Due to the low diffusion rates of ions within the CuFeS 2 passive film and due to an increase in the resistance to the transfer of electrons at the electrode/film interface, the activity of FeS 2 for the reduction of Fe 3+ ions was also reduced by a factor of 2.3 even though FeS 2 was not exposed to any chemical treatment. The results in this work indicate that the dissolution rate of the fresh CuFeS 2 electrode was controlled by the reduction of Fe 3+ ions whereas for the passivated CuFeS 2 electrode the dissolution rate was controlled by diffusion within the passive film

Sheet resistance, transmittance, and chromatic property of CNTs coated with PEDOT:PSS films for transparent electrodes of touch screen panels

Energy Technology Data Exchange (ETDEWEB)

Kim, Bu-Jong; Han, Sang-Hoon; Park, Jin-Seok

2014-12-01

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.

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)

Kim, Bu-Jong; Han, Sang-Hoon; Park, Jin-Seok

2014-01-01

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

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors.

Science.gov (United States)

Yang, Jiang; Kwak, Tae-Joon; Zhang, Xiaodong; McClain, Robert; Chang, Woo-Jin; Gunasekaran, Sundaram

2016-11-22

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (µPAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

Gold nanoparticles embedded electropolymerized thin film of pyrimidine derivative on glassy carbon electrode for highly sensitive detection of l-cysteine.

Science.gov (United States)

Kannan, Ayyadurai; Sevvel, Ranganathan

2017-09-01

This paper demonstrates the fabrication of novel gold nanoparticles incorporated poly (4-amino-6-hydroxy-2-mercaptopyrimidine) (Nano-Au/Poly-AHMP) film modified glassy carbon electrode and it is employed for highly sensitive detection of l-cysteine (CYS). The modified electrode was characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). SEM images of modified electrode revealed the homogeneous distribution of gold nanoparticles on poly (4-amino-6-hydroxy-2-mercaptopyrimidine) thin film modified glassy carbon electrode. The modified electrode was successfully utilized for highly selective and sensitive determination of l-cysteine at physiological pH7.0. The present electrochemical sensor successfully resolved the voltammetric signals of ascorbic acid (AA) and l-cysteine with peak separation of 0.510V. To the best of our knowledge, this is the first report of larger peak separation between AA and CYS. Wide linear concentration ranges (2μM-500μM), low detection limit (0.020μM), an excellent reproducibility and stability are achieved for cysteine sensing with this Nano-Au/Poly-AHMP/GCE. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Multiferroic properties of the Y2BiFe5O12 garnet

Science.gov (United States)

Durán, A.; Ostos, C.; Arnache, O.; Siqueiros, J. M.; García-Guaderrama, M.

2017-10-01

Multiferroic properties are found in the Yttrium iron garnet (YIG) modified with Bi3+. The X-ray diffraction pattern shows that the Bi3+ ion is completely soluble up to one-third of the Y molar content forming the Y2BiFe5O12 compound as a single phase. Structural analysis did not show signals of other incipient non-centrosymmetric phases in the compound. However, the dielectric and polarization studies clearly exhibit a typical relaxor ferroelectric behavior at room temperature where the maxima of the broad permittivity peaks shift with frequency. The quadratic diffuseness coefficient obtained from the modified Curie-Weiss law suggests polar nanoregion switching in a broad temperature range. Using the Vogel-Fulcher relationship, the activation energy and freezing temperature were found to be 243.1 meV and 322.6 K, respectively. Here, the main contribution to relaxation comes from thermally activated reorientation of the dipole moments, as confirmed by the well-defined hysteresis loops in the P-E measurements. The dipole fluctuations arise from the compositional disorder induced by Bi3+ ions randomly distributed in the lattice, having thermally active polarization fluctuations above the freezing temperature, Tf. Furthermore, it is found that Bi3+ preserves the magnetization features of this compound. Thus, the Bi3+ modified YIG compound is found to be a multiferroic material at room temperature.

Electrode patterning of ITO thin films by high repetition rate fiber laser

International Nuclear Information System (INIS)

Lin, H.K.; Hsu, W.C.

2014-01-01

Indium tin oxide (ITO) thin films are deposited on glass substrates using a radio frequency magnetron sputtering system. As-deposited ITO thin film was 100 nm in thickness and a transmittance of ITO film on glass substrate was 79% at 550 nm. Conductive electrodes are then patterned on the ITO films using a high repetition rate fiber laser system followed by a wet chemical etching process. The electrical, optical and structural properties of the patterned samples are evaluated by means of a four-point probe technique, spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the samples annealed with a pulse repetition rate of 150 kHz or 400 kHz have a low sheet resistivity of 21 Ω/□ and a high optical transmittance of 90%. In addition, it is shown that a higher pulse repetition rate reduces both the residual stress and the surface roughness of the patterned specimens. Therefore, the present results suggest that a pulse repetition rate of 400 kHz represents the optimal processing condition for the patterning of crack-free ITO-coated glass substrates with good electrical and optical properties.

Electrode patterning of ITO thin films by high repetition rate fiber laser

Energy Technology Data Exchange (ETDEWEB)

Lin, H.K., E-mail: HKLin@mail.npust.edu.tw; Hsu, W.C.

2014-07-01

Indium tin oxide (ITO) thin films are deposited on glass substrates using a radio frequency magnetron sputtering system. As-deposited ITO thin film was 100 nm in thickness and a transmittance of ITO film on glass substrate was 79% at 550 nm. Conductive electrodes are then patterned on the ITO films using a high repetition rate fiber laser system followed by a wet chemical etching process. The electrical, optical and structural properties of the patterned samples are evaluated by means of a four-point probe technique, spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the samples annealed with a pulse repetition rate of 150 kHz or 400 kHz have a low sheet resistivity of 21 Ω/□ and a high optical transmittance of 90%. In addition, it is shown that a higher pulse repetition rate reduces both the residual stress and the surface roughness of the patterned specimens. Therefore, the present results suggest that a pulse repetition rate of 400 kHz represents the optimal processing condition for the patterning of crack-free ITO-coated glass substrates with good electrical and optical properties.

Effect of micro-patterned fluorine-doped tin oxide films on electrochromic properties of Prussian blue films

International Nuclear Information System (INIS)

Lee, Kyuha; Kim, A-Young; Park, Ji Hun; Jung, Hun-Gi; Choi, Wonchang; Lee, Hwa Young; Lee, Joong Kee

2014-01-01

Graphical abstract: - Highlights: • PB-based ECD employed micro-patterned FTO electrode was fabricated. • Effect of interface morphology on electrochromic characteristics was examined. • Electrochromic properties were enhanced by employing a patterned interface. - Abstract: The effect of interface morphology on electrochromic characteristics was examined for an electrochromic device (ECD). Micro-patterned fluorine-doped tin oxide (FTO) films were fabricated using a photolithography process. Prussian blue (PB) films were then deposited on the patterned FTO films. The surface areas of both PB films and FTO films were increased by patterning. ECDs were assembled using patterned PB/FTO films as the electrochromic electrode, bare FTO films as the counter electrode, and an electrolyte containing LiClO 4 salt. The increased effective surface area of the patterned PB/FTO electrode boosted the mobility of ions at the interphase between the electrolyte and PB electrode, and the electron transfer between PB films and FTO films. As a result, electrochromic properties such as transmittance and response time were significantly improved by employing the patterned FTO films as the transparent conductive oxide layer of the electrochromic electrode

Electrocatalytic activity of electropolymerized cobalt tetraaminophthalocyanine film modified electrode towards 6-mercaptopurine and 2-mercaptobenzimidazole

OpenAIRE

Fan, Jie-Ping; Zhang, Xiao-Min; Ying, Min

2010-01-01

The electrocatalytic activity of electropolymerized cobalt tetraaminophthalocyanine (poly-CoTAPc) film modified on the glassy carbon electrode (GCE) towards 6-mercaptopurine (6MP) and 2-Mercaptobenzimidazole (MBI) was studied. Comparing with the case at the unmodified GCE, the poly-CoTAPc film decreased the overpotential of oxidation of 6MP (1.0 x 10-3 mol L-1) and MBI (1.0 x 10-3 mol L-1) by 335 and 189 mV, respectively, and increased the peak current by about 3 and 2 times, respectively, wh...

Horseradish Peroxidase (HRP Immobilized Poly(aniline-co-m-aminophenol Film Electrodes–fabrication and Evaluation as Hydrogen Peroxide Sensor

Directory of Open Access Journals (Sweden)

Seong-Ho Choi

2007-05-01

Full Text Available Enzyme modified electrodes were fabricated with poly(aniline-co-m-aminophenol. Electrochemical polymerization of aniline and m-aminophenol wasperformed to get the film of copolymer on the surface of gold electrode. Modifiedelectrodes were fabricated by two methods, physical entrapment and covalent cross-linking.In one of the method, gold nanoparticles were loaded into the copolymer film andhorseradish peroxidase (HRP was immobilized into the Au nanoparticle loaded copolymerfilm through physical entrapment. In the other method, the amino and -OH groups in thecopolymer are utilized to form covalent functionalization with HRP via glutaric dialdehydeas cross-linker/mediator. The conducting copolymer/enzyme modified electrodes preparedby physical entrapment/covalent functionalization of enzyme were tested forelectrocatalytic activities towards sensing of H2O2. Amperometric results indicate thatenzyme modified electrode via physical entrapment possesses better electrocatalyticperformance over covalent functionalized enzyme electrode.

Layer-by-Layer Self-Assembled Graphene Multilayer Films via Covalent Bonds for Supercapacitor Electrodes

Directory of Open Access Journals (Sweden)

Xianbin Liu

2015-05-01

Full Text Available To maximize the utilization of its single-atom thin nature, a facile scheme to fabricate graphene multilayer films via a layer-by-layer self-assembled process was presented. The structure of multilayer films was constructed by covalently bonding graphene oxide (GO using p-phenylenediamine (PPD as a covalent cross-linking agent. The assembly process was confirmed to be repeatable and the structure was stable. With the π-π conjugated structure and a large number of spaces in the framework, the graphene multi‐ layer films exhibited excellent electrochemical perform‐ ance. The uniform ultrathin electrode exhibited a capacitance of 41.71 μF/cm2 at a discharge current of 0.1 μA/cm2, and displayed excellent stability of 88.9 % after 1000 charge-discharge cycles.

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)

Shajdarova, L.G.; Gedmina, A.V.; Chelnokova, I.A.; Budnikov, G.K.

2008-01-01

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 [ru

Spectroelectrochemical study of the adsorption of acetate anions at gold single crystal and thin-film electrodes

International Nuclear Information System (INIS)

Berna, Antonio; Delgado, Jose Manuel; Orts, Jose Manuel; Rodes, Antonio; Feliu, Juan Miguel

2008-01-01

Acetate adsorption at gold electrodes is studied in perchloric acid solutions by cyclic voltammetry and in-situ infrared spectroscopy. External reflection measurements, performed with gold single crystal electrodes, are combined with Surface Enhanced Infrared Reflection Absorption Spectroscopy experiments under attenuated total reflection conditions (ATR-SEIRAS) carried out with sputtered gold thin-film electrodes. Theoretical harmonic IR frequencies of acetate species adsorbed with different geometries on Au clusters with (1 1 1), (1 0 0) and (1 1 0) orientations have been obtained from B3LYP/LANL2DZ, 6-31 + G* calculations. The theoretical and experimental results confirm that, irrespective of the surface crystallographic orientation, bonding of acetate to the surface involves the two oxygen atoms of the carboxylate group, with the OCO plane perpendicular to the metal surface. DFT calculations reveal also that the total charge of the metal cluster-acetate supermolecule has small effect on the vibrational frequencies of adsorbed acetate species. Both the external and the internal reflection measurements show the co-adsorption of acetate and perchlorate anions. Step-scan measurements carried out with the gold thin-film electrodes have allowed the monitoring of the time-dependent behaviour of perchlorate, acetate and water bands in potential step experiments. Acetate adsorption under those conditions is shown to involve perchlorate desorption and to follow a Langmuir-type kinetics. The step-scan spectra also show the rise and decay of transient water structures with parallel time-dependent shifts of the background intensity in the infrared spectra

Comparison of lead zirconate titanate thin films on ruthenium oxide and platinum electrodes

International Nuclear Information System (INIS)

Bursill, L.A.; Reaney, I.M.

1994-01-01

High-resolution and bright- and dark-field transmission electron microscopy are used to characterize and compare the interface structures and microstructure of PZT/RuO 2 /SiO 2 /Si and PZT/Pt/Ti/SiO 2 /Si ferroelectric thin films, with a view to understanding the improved fatigue characteristics of PZT thin films with RuO 2 electrodes. The RuO 2 /PZT interface consists of a curved pseudoperiodic minimal surface. The interface is chemically sharp with virtually no intermixing of RuO 2 and PZT, as evidenced by the atomic resolution images as well as energy dispersive X-ray analysis. A nanocrystalline pyrochlore phase Pb 2 ZrTiO 7-x (x ≠ 1) was found on the top surface of the PZT layer. The PZT/Pt/Ti/SiO 2 /Si thin film was well-crystallized and showed sharp interfaces throughout. Possible reasons for the improved fatigue characteristics of PZT/RuO 2 /SiO 2 /Si thin films are discussed. 13 refs; 7 figs

Comparison of lead zirconate titanate thin films on ruthenium oxide and platinum electrodes

Energy Technology Data Exchange (ETDEWEB)

Bursill, L A; Reaney, I M

1994-12-31

High-resolution and bright- and dark-field transmission electron microscopy are used to characterize and compare the interface structures and microstructure of PZT/RuO{sub 2}/SiO{sub 2}/Si and PZT/Pt/Ti/SiO{sub 2}/Si ferroelectric thin films, with a view to understanding the improved fatigue characteristics of PZT thin films with RuO{sub 2} electrodes. The RuO{sub 2}/PZT interface consists of a curved pseudoperiodic minimal surface. The interface is chemically sharp with virtually no intermixing of RuO{sub 2} and PZT, as evidenced by the atomic resolution images as well as energy dispersive X-ray analysis. A nanocrystalline pyrochlore phase Pb{sub 2}ZrTiO{sub 7-x} (x {ne} 1) was found on the top surface of the PZT layer. The PZT/Pt/Ti/SiO{sub 2}/Si thin film was well-crystallized and showed sharp interfaces throughout. Possible reasons for the improved fatigue characteristics of PZT/RuO{sub 2}/SiO{sub 2}/Si thin films are discussed. 13 refs; 7 figs.

Flexible Electrode Design: Fabrication of Freestanding Polyaniline-Based Composite Films for High-Performance Supercapacitors.

Science.gov (United States)

Khosrozadeh, Ali; Darabi, Mohammad Ali; Xing, Malcolm; Wang, Quan

2016-05-11

Polyaniline (PANI) is a promising pseudocapacitance electrode material. However, its structural instability leads to low cyclic stability and limited rate capability which hinders its practical applications. In view of the limitations, flexible PANI-based composite films are developed to improve the electrochemical performance of electrode materials. We report in the research a facile and cost-effective approach for fabrication of a high-performance supercapacitor (SC) with excellent cyclic stability and tunable energy and power densities. SC electrode containing a very high mass loading of active materials is a flexible film of PANI, tissue wiper-based cellulose, graphite-based exfoliated graphite (ExG), and silver nanoparticles with potential applications in wearable electronics. The optimum preparation weight ratios of silver nitrate/aniline and ExG/aniline used in the research are estimated to be 0.18 and 0.65 (or higher), respectively. Our results show that an ultrahigh capacitance of 3.84 F/cm(2) (240.10 F/g) at a discharge rate of 5 mA can be achieved. In addition, our study shows that the power density can be increased from 1531.3 to 3000 W/kg by selecting the weight ratio of ExG/aniline to be more than 0.65, with a sacrifice in the energy density. The obtained promising electrochemical properties are found to be mainly attributed to an effective combination of PANI, ExG, cushiony cellulose scaffold, and silver as well as the porosity of the composite.

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

International Nuclear Information System (INIS)

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

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. (paper)

Energy harvesting efficiency of piezoelectric polymer film with graphene and metal electrodes.

Science.gov (United States)

Park, Sanghoon; Kim, Yura; Jung, Hyosub; Park, Jun-Young; Lee, Naesung; Seo, Yongho

2017-12-11

In this study, we investigated an energy harvesting effect of tensile stress using piezoelectric polymers and flexible electrodes. A chemical-vapor-deposition grown graphene film was transferred onto both sides of the PVDF and P(VDF-TrFE) films simultaneously by means of a conventional wet chemical method. Output voltage induced by sound waves was measured and analyzed when a mechanical tension was applied to the device. Another energy harvester was made with a metallic electrode, where Al and Ag were deposited by using an electron-beam evaporator. When acoustic vibrations (105 dB) were applied to the graphene/PVDF/graphene device, an induced voltage of 7.6 V pp was measured with a tensile stress of 1.75 MPa, and this was increased up to 9.1 V pp with a stress of 2.18 MPa for the metal/P(VDF-TrFE)/metal device. The 9 metal/PVDF/metal layers were stacked as an energy harvester, and tension was applied by using springs. Also, we fabricated a full-wave rectifying circuit to store the electrical energy in a 100 μF capacitor, and external vibration generated the electrical charges. As a result, the stored voltage at the capacitor, obtained from the harvester via a bridge diode rectifier, was saturated to ~7.04 V after 180 s charging time.

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.

Pulsed voltage deposited lead selenide thin film as efficient counter electrode for quantum-dot-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Jin, Bin Bin [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Department of Chemical Engineering, Institute of Chemical Industry, Shaanxi Institute of Technology, Xi’an 710300 (China); Wang, Ye Feng [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Wang, Xue Qing [Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China); Zeng, Jing Hui, E-mail: jhzeng@ustc.edu [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China)

2016-04-30

Highlights: • PbSe thin film is deposited on FTO glass by a pulse voltage electrodeposition method. • The thin film is used as counter electrode (CE) in quantum dot-sensitized solar cell. • Superior electrocatalytic activity and stability in the polysulfide electrolyte is received. • The narrow band gap characteristics and p-type conductivity enhances the cell efficiency. • An efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells. - Abstract: Lead selenide (PbSe) thin films were deposited on fluorine doped tin oxide (FTO) glass by a facile one-step pulse voltage electrodeposition method, and used as counter electrode (CE) in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). A power conversion efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells, which is much better than that of 2.39% received using Pt CEs. The enhanced performance is attributed to the extended absorption in the near infrared region, superior electrocatalytic activity and p-type conductivity with a reflection of the incident light at the back electrode in addition. The physical and chemical properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), reflectance spectra, electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The present work provides a facile pathway to an efficient CE in the QDSSCs.

Voltammetry of osmium-modified DNA at a mercury film electrode application in detecting DNA hybridization

Czech Academy of Sciences Publication Activity Database

Kostečka, Pavel; Havran, Luděk; Pivoňková, Hana; Fojta, Miroslav

2004-01-01

Roč. 63, 1-2 (2004), s. 245-248 ISSN 1567-5394 R&D Projects: GA AV ČR IAA4004108; GA AV ČR KJB4004302 Institutional research plan: CEZ:AV0Z5004920 Keywords : osmium * DNA hybridization * mercury film electrode Subject RIV: BO - Biophysics Impact factor: 2.261, year: 2004

Flexible and Transparent Plastic Electrodes Composed of Reduced Graphene Oxide/Polyaniline Films for Supercapacitor Application

International Nuclear Information System (INIS)

Sarker, Ashis K.; Hong, Jongdal

2014-01-01

In this article, we described about the preparation and electrochemical properties of a flexible energy storage system based on a plastic polyethylene terephthalate (PET) substrate. The PET treated with UV/ozone was fabricated with multilayer films composed of 30 polyaniline (PANi)/graphene oxide (GO) bilayers using layerby-layer assembly of positively charged PANi and negatively charged GO. The conversion of GO to the reduced graphene oxide (RGO) in the multilayer film was achieved using hydroiodic acid vapor at 100 .deg. C, whereby PANi structure remained nearly unchanged except a little reduction of doping state. Cyclic voltammetry and charge/discharge curves of 30 PANi/RGO bilayers on PET substrate (shorten to PANi-RGO 30 /PET) exhibited an excellent volumetric capacitance, good cycling stability, and rapid charge/discharge rates despite no use of any metal current collectors. The specific capacitance from charge/discharge curve of the PANi-RGO 30 /PET electrode was found to be 529 F/cm 3 at a current density of 3 A/cm 3 , which is one of the best values yet achieved among carbon-based materials including conducting polymers. Furthermore, the intrinsic electrical resistance of the PANi-RGO 30 /PET electrodes varied within 20% range during 200 bending cycles at a fixed bend radius of 2.2 mm, indicating the increase in their flexibility by a factor of 225 compared with the ITO/PET electrode

NiCo2S4 nanosheet-decorated 3D, porous Ni film@Ni wire electrode materials for all solid-state asymmetric supercapacitor applications.

Science.gov (United States)

Saravanakumar, Balasubramaniam; Jayaseelan, Santhana Sivabalan; Seo, Min-Kang; Kim, Hak-Yong; Kim, Byoung-Suhk

2017-12-07

Wire type supercapacitors with high energy and power densities have generated considerable interest in wearable applications. Herein, we report a novel NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode for high performance supercapacitor application. In this work, a facile method is introduced to fabricate a 3D, porous Ni film deposited on a Ni wire as a flexible electrode, followed by decoration with NiCo 2 S 4 as an electroactive material. The fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire electrode displays a superior performance with an areal and volumetric capacitance of 1.228 F cm -2 and 199.74 F cm -3 , respectively, at a current density of 0.2 mA cm -1 with a maximum volumetric energy and power density (E V : 6.935 mW h cm -3 ; P V : 1.019 W cm -3 ). Finally, the solid state asymmetric wire type supercapacitor is fabricated using the fabricated NiCo 2 S 4 -decorated 3D, porous Ni film@Ni wire as a positive electrode and N-doped reduced graphene oxide (N-rGO) as a negative electrode and this exhibits good areal and volumetric capacitances of C A : 0.12 F cm -2 and C V : 19.57 F cm -2 with a higher rate capability (92%). This asymmetric wire type supercapacitor demonstrates a low leakage current and self-discharge with a maximum volumetric energy (E V : 5.33 mW h cm -3 ) and power (P V : 855.69 mW cm -3 ) density.

Effect of micro-patterned fluorine-doped tin oxide films on electrochromic properties of Prussian blue films

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyuha [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, A-Young [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Material Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Park, Ji Hun; Jung, Hun-Gi; Choi, Wonchang; Lee, Hwa Young [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Joong Kee, E-mail: leejk@kist.re.kr [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

2014-09-15

Graphical abstract: - Highlights: • PB-based ECD employed micro-patterned FTO electrode was fabricated. • Effect of interface morphology on electrochromic characteristics was examined. • Electrochromic properties were enhanced by employing a patterned interface. - Abstract: The effect of interface morphology on electrochromic characteristics was examined for an electrochromic device (ECD). Micro-patterned fluorine-doped tin oxide (FTO) films were fabricated using a photolithography process. Prussian blue (PB) films were then deposited on the patterned FTO films. The surface areas of both PB films and FTO films were increased by patterning. ECDs were assembled using patterned PB/FTO films as the electrochromic electrode, bare FTO films as the counter electrode, and an electrolyte containing LiClO{sub 4} salt. The increased effective surface area of the patterned PB/FTO electrode boosted the mobility of ions at the interphase between the electrolyte and PB electrode, and the electron transfer between PB films and FTO films. As a result, electrochromic properties such as transmittance and response time were significantly improved by employing the patterned FTO films as the transparent conductive oxide layer of the electrochromic electrode.

Development of the α-IGZO/Ag/α-IGZO Triple-Layer Structure Films for the Application of Transparent Electrode.

Science.gov (United States)

Chen, Kun-Neng; Yang, Cheng-Fu; Wu, Chia-Ching; Chen, Yu-Hsin

2017-02-24

We investigated the structural, optical, and electrical properties of amorphous IGZO/silver/amorphous IGZO (α-IGZO/Ag/α-IGZO) triple-layer structures that were deposited at room temperature on Eagle XG glass and flexible polyethylene terephthalate substrates through the sputtering method. Thin Ag layers with different thicknesses were inserted between two IGZO layers to form a triple-layer structure. Ag was used because of its lower absorption and resistivity. Field emission scanning electron microscopy measurements of the triple-layer structures revealed that the thicknesses of the Ag layers ranged from 13 to 41 nm. The thickness of the Ag layer had a large effect on the electrical and optical properties of the electrodes. The optimum thickness of the Ag metal thin film could be evaluated according to the optical transmittance, electrical conductivity, and figure of merit of the electrode. This study demonstrates that the α-IGZO/Ag/α-IGZO triple-layer transparent electrode can be fabricated with low sheet resistance (4.2 Ω/□) and high optical transmittance (88.1%) at room temperature without postannealing processing on the deposited thin films.

Electrochemical fabrication of TiO2 nanoparticles/[BMIM]BF4 ionic liquid hybrid film electrode and its application in determination of p-acetaminophen

International Nuclear Information System (INIS)

Wang, Bin; Li, Yuan; Qin, Xianjing; Zhan, Guoqing; Ma, Ming; Li, Chunya

2012-01-01

A water soluble ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF 4 ), was incorporated into TiO 2 nanoparticles to fabricate a hybrid film modified glassy carbon electrode (nano‐TiO 2 /[BMIM]BF 4 /GCE) through electrochemical deposition in a tetrabutyltitanate sol solution containing [BMIM]BF 4 . The obtained nano‐TiO 2 /[BMIM]BF 4 /GCEs were characterized scanning electronic microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). Electrochemical behaviors of p‐acetaminophen at the nano‐TiO 2 /[BMIM]BF 4 /GCEs were thoroughly investigated. Compared to the redox reaction of p‐acetaminophen using an unmodified electrode under the same conditions, a new reduction peak was observed clearly at 0.26 V with the modified electrode. In addition, the peak potential for the oxidation of p‐acetaminophen was found to shift negatively about 90 mV and the current response increased significantly. These changes indicate that the nano‐TiO 2 /[BMIM]BF 4 hybrid film can improve the redox reactions of p‐acetaminophen in aqueous medium. Under optimum conditions, a linear relationship was obtained for the p‐acetaminophen solutions with concentration in the range from 5.0 × 10 −8 to 5.0 × 10 −5 M. The estimated detection limit was 1.0 × 10 −8 M (S/N = 3). The newly developed method was applied for the determination of p-acetaminophen in urine samples. - Highlights: ► Nano-TiO 2 /[BMIM]BF 4 hybrid film electrode was fabricated with electrodeposition. ► Voltammetric behavior of p-acetaminophen at the obtained electrode was investigated. ► The hybrid film electrode shows good electrocatalytic response to p-acetaminophen. ► p-acetaminophen in urine samples was successfully determined.

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.

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.

Facile preparation of molecularly imprinted polypyrrole-graphene-multiwalled carbon nanotubes composite film modified electrode for rutin sensing.

Science.gov (United States)

Yang, Lite; Yang, Juan; Xu, Bingjie; Zhao, Faqiong; Zeng, Baizhao

2016-12-01

In this paper, a novel molecularly imprinted composite film modified electrode was presented for rutin (RT) detection. The modified electrode was fabricated by electropolymerization of pyrrole on a graphene-multiwalled carbon nanotubes composite (G-MWCNTs) coated glassy carbon electrode in the presence of RT. The netlike G-MWCNTs composite, prepared by in situ hydrothermal process, had high conductivity and electrocatalytic activity. At the resulting MIP/G-MWCNTs/GCE electrode RT could produce a sensitive anodic peak in pH 1.87 Britton-Robinson buffer solution. The factors affecting the electrochemical behavior and response of RT on the modified electrode were carefully investigated and optimized. Under the selected conditions, the linear response range of RT was 0.01-1.0μmolL -1 and the detection limit (S/N=3) was 5.0nmolL -1 . The electrode was successfully applied to the determination of RT in buckwheat tea and orange juice samples, and the recoveries for standards added were 93.4-105%. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancement of the electrical characteristics of thin-film transistors with indium-zinc-tin oxide/Ag/indium-zinc-tin oxide multilayer electrodes

Science.gov (United States)

Oh, Dohyun; Yun, Dong Yeol; Cho, Woon-Jo; Kim, Tae Whan

2014-08-01

Transparent indium-zinc-tin oxide (IZTO)-based thin-film transistors (TFTs) with IZTO/Ag/IZTO multilayer electrodes were fabricated on glass substrates using a tilted dual-target radio-frequency magnetron sputtering system. The IZTO TFTs with IZTO/Ag/IZTO multilayer electrodes exhibited a high optical transmittance in a visible region. The threshold voltage, the mobility, and the on/off-current ratio of the TFTs with IZTO/Ag/IZTO multilayer electrodes were enhanced in comparison with those of the TFTs with ITO electrodes. The source/drain contact resistance of the IZTO TFTs with IZTO/Ag/IZTO multilayer electrodes was smaller than that of the IZTO TFTs with ITO electrodes, resulting in enhancement of their electrical characteristics.

A thin film approach for SiC-derived graphene as an on-chip electrode for supercapacitors

Science.gov (United States)

Ahmed, Mohsin; Khawaja, Mohamad; Notarianni, Marco; Wang, Bei; Goding, Dayle; Gupta, Bharati; Boeckl, John J.; Takshi, Arash; Motta, Nunzio; Saddow, Stephen E.; Iacopi, Francesca

2015-10-01

We designed a nickel-assisted process to obtain graphene with sheet resistance as low as 80 Ω square-1 from silicon carbide films on Si wafers with highly enhanced surface area. The silicon carbide film acts as both a template and source of graphitic carbon, while, simultaneously, the nickel induces porosity on the surface of the film by forming silicides during the annealing process which are subsequently removed. As stand-alone electrodes in supercapacitors, these transfer-free graphene-on-chip samples show a typical double-layer supercapacitive behaviour with gravimetric capacitance of up to 65 F g-1. This work is the first attempt to produce graphene with high surface area from silicon carbide thin films for energy storage at the wafer-level and may open numerous opportunities for on-chip integrated energy storage applications.

Two Ti13-oxo-clusters showing non-compact structures, film electrode preparation and photocurrent properties.

Science.gov (United States)

Hou, Jin-Le; Luo, Wen; Wu, Yin-Yin; Su, Hu-Chao; Zhang, Guang-Lin; Zhu, Qin-Yu; Dai, Jie

2015-12-14

Two benzene dicarboxylate (BDC) and salicylate (SAL) substituted titanium-oxo-clusters, Ti13O10(o-BDC)4(SAL)4(O(i)Pr)16 (1) and Ti13O10(o-BDC)4(SAL-Cl)4(O(i)Pr)16 (2), are prepared by one step in situ solvothermal synthesis. Single crystal analysis shows that the two Ti13 clusters take a paddle arrangement with an S4 symmetry. The non-compact (non-sphere) structure is stabilized by the coordination of BDC and SAL. Film photoelectrodes are prepared by the wet coating process using the solution of the clusters and the photocurrent response properties of the electrodes are studied. It is found that the photocurrent density and photoresponsiveness of the electrodes are related to the number of coating layers and the annealing temperature. Using ligand coordinated titanium-oxo-clusters as the molecular precursors of TiO2 anatase films is found to be effective due to their high solubility, appropriate stability in solution and hence the easy controllability.

Indirect potentiometric titration of ascorbic acid in pharmaceutical preparations using copper based mercury film electrode.

Science.gov (United States)

Abdul Kamal Nazer, Meeran Mohideen; Hameed, Abdul Rahman Shahul; Riyazuddin, Patel

2004-01-01

A simple and rapid potentiometric method for the estimation of ascorbic acid in pharmaceutical dosage forms has been developed. The method is based on treating ascorbic acid with iodine and titration of the iodide produced equivalent to ascorbic acid with silver nitrate using Copper Based Mercury Film Electrode (CBMFE) as an indicator electrode. Interference study was carried to check possible interference of usual excipients and other vitamins. The precision and accuracy of the method was assessed by the application of lack-of-fit test and other statistical methods. The results of the proposed method and British Pharmacopoeia method were compared using F and t-statistical tests of significance.

Fully-flexible supercapacitors using spray-deposited carbon-nanotube films as electrodes

Science.gov (United States)

Lee, Churl Seung; Bae, Joonho

2013-12-01

Fully-flexible carbon-nanotube-based supercapacitors were successfully fabricated using a spray method. For electrodes, multiwalled carbon-nanotube films sprayed on polyethylene terephthalate (PET) substrates were employed. Thin Al films on PET were used as current collectors. The electrolyte was 1 M KNO3. Cyclic voltammetry and galvanostatic charge-discharge measurements on the flexible supercapacitors revealed that the area-specific capacitance was 0.11 mF/cm2. Electrochemical impedance spectroscopy of the supercapacitors resulted in a low internal resistance (3.7 Ω). The energy density and the power density of the flexible supercapacitor were measured to be 3.06 × 10-8 Wh/cm2 and 2.65 × 10-7 W/cm2, respectively. The Bode | z| and phase-angle plots showed that the supercapacitors functioned close to ideal capacitors at the frequencies near 2 kHz. These results indicate that the spray deposition method of carbon nanotubes could be promising for fabricating flexible energy devices or electronics.

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...

Study and Electrochemical Determination of Tyrosine at Graphene Nanosheets Composite Film Modified Glassy Carbon Electrode

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M. Behpour

2013-06-01

Full Text Available A graphene nanosheets (GNS film coated glassy carbon electrode (GCE was fabricated for sensitive determination of tyrosine (Tyr. The GNS-based sensor was characterized by scanning electron microscope and electrochemical impedance spectroscopy. The voltammetric techniques were employed to study electro-oxidation of Tyr. The results revealed that the modified electrode showed an electrocatalytic activity toward the anodic oxidation of Tyr by a marked enhancement in the current intensity and the shift in the oxidation potential to lower values (50 mV in comparison with the bare GCE. Some kinetic parameters such as the electron transfer coefficient (α were also determined for the Tyr oxidation. The detection limit  for Tyr was found to be 2.0×10-8 M (n=9, and the peak current increases linearly with the Tyr concentration within the molar concentration ranges of 5.0 ×10-6 to 1.2 ×10-4 M. The modified electrode shows good sensitivity, selectivity and stability. The prepared electrode was applied for the determination of Tyr in real sample.

Poly(o-aminophenol) film electrodes synthesis, transport properties and practical applications

CERN Document Server

Tucceri, Ricardo

2014-01-01

This review book is concerned with the synthesis, charge transport properties and practical applications of poly (o-aminophenol) (POAP) film electrodes. It is divided into three parts. The first one has a particular emphasis on problems of synthesis and structure of POAP. The second part deals with the mechanism of charge transfer and charge transport processes occurring in the course of the redox reactions of POAP. The third part describes the promising applications of POAP in the different fields of sensors, electrocatalysis, bioelectrochemistry, corrosion protection, among others. This review covers the literature on POAP in the time period comprised between 1987 and 2013.

Lithium-Ion (de)insertion reaction of Germanium thin-film electrodes : an electrochemical and in situ XRD study

NARCIS (Netherlands)

Baggetto, L.; Notten, P.H.L.

2009-01-01

Germanium is a promising negative electrode candidate for lithium-ion thin-film batteries because of its very high theoretical storage capacity. When assuming full conversion of the material into the room-temperature equilibrium lithium saturated germanium phase, a theoretical capacity of or of

Conducting polymers based counter electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Veerender, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Saxena, Vibha, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gusain, Abhay, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Jha, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Koiry, S. P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Chauhan, A. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Aswal, D. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gupta, S. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

2014-04-24

Conducting polymer films were synthesized and employed as an alternative to expensive platinum counter electrodes for dye-sensitized solar cells. poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) thin films were spin-coated and polypyrrole films were electrochemically deposited via cyclic voltammetry method on ITO substrates. The morphology of the films were imaged by SEM and AFM. These films show good catalytic activity towards triiodide reduction as compared to Pt/FTO electrodes. Finally the photovoltaic performance of DSSC fabricated using N3 dye were compared with PT/FTO, PEDOT/ITO, and e-PPy counter electrodes.

Wrinkle-free graphene electrodes in zinc tin oxide thin-film transistors for large area applications

Science.gov (United States)

Lee, Se-Hee; Kim, Jae-Hee; Park, Byeong-Ju; Park, Jozeph; Kim, Hyun-Suk; Yoon, Soon-Gil

2017-02-01

Wrinkle-free graphene was used to form the source-drain electrodes in thin film transistors based on a zinc tin oxide (ZTO) semiconductor. A 10 nm thick titanium adhesion layer was applied prior to transferring a conductive graphene film on top of it by chemical detachment. The formation of an interlayer oxide between titanium and graphene allows the achievement of uniform surface roughness over the entire substrate area. The resulting devices were thermally treated in ambient air, and a substantial decrease in field effect mobility is observed with increasing annealing temperature. The increase in electrical resistivity of the graphene film at higher annealing temperatures may have some influence, however the growth of the oxide interlayer at the ZTO/Ti boundary is suggested to be most influential, thereby inducing relatively high contact resistance.

Direct electrochemistry and electrocatalysis of hemoglobin at three-dimensional gold film electrode modified with self-assembled monolayers of 3-mercaptopropylphosphonic acid

International Nuclear Information System (INIS)

Chen Yu; Yang Xiaojing; Guo Lirong; Li Jing; Xia Xinghua; Zheng Limin

2009-01-01

Multilayered hemoglobin (Hb) molecules were successfully immobilized on three-dimensional gold film electrode modified with self-assembled monolayers (SAMs) of 3-mercaptopropylphosphonic acid. Direct electrochemistry of the immobilized multilayered Hb occurs with high thermal stability and electrochemical stability. In the multilayered Hb film, the most inner Hb molecules can directly transfer electron with the electrode, while the Hb protein beyond this layer communicates electron with the electrode via protein-protein electron exchange. In addition, the proposed functional interface can greatly enhance electron transfer rate of the immobilized Hb protein (k s = 15.8 ± 2.0 s -1 ) due to the increase of roughness of the gold substrate. Under optimized experimental conditions, the multilayered Hb film displays good bioelectrocatalytic activity toward the reduction of hydrogen peroxide. This electrochemical sensor shows fast response (less than 1 s), wide linear range (7.8 x 10 -8 to 9.1 x 10 -5 M) and low detection limit (2.5 x 10 -8 M), which can be attributed to good mass transport, large Hb proteins loading per unit area and fast electron transfer rate of Hb protein.

Platinum/titanium bilayer deposited on polymer film as efficient counter electrodes for plastic dye-sensitized solar cells

International Nuclear Information System (INIS)

Ikegami, M.; Miyoshi, K.; Miyasaka, T.; Teshima, K.; Wei, T. C.; Wan, C. C.; Wang, Y. Y.

2007-01-01

A surface-rich platinum/titanium bilayer was deposited on poly(ethylene naphthalate) film by vacuum sputtering as counterelectrode for plastic dye-sensitized solar cells (DSSCs). Compared to the electrodes made of pure Pt layer, this electrode maintained similar electrochemical catalytic effect at relative low Pt usage. Current-voltage characteristics of the plastic DSSC at this stage stand at 0.69 V on V OC , 9.97 mA/cm 2 on I SC , 0.69 on fill factor, and 4.31% cell efficiency under AM1.5, 100 mW/cm 2 illumination

A thin film approach for SiC-derived graphene as an on-chip electrode for supercapacitors

International Nuclear Information System (INIS)

Ahmed, Mohsin; Wang, Bei; Goding, Dayle; Iacopi, Francesca; Khawaja, Mohamad; Notarianni, Marco; Takshi, Arash; Saddow, Stephen E; Gupta, Bharati; Motta, Nunzio; Boeckl, John J

2015-01-01

We designed a nickel-assisted process to obtain graphene with sheet resistance as low as 80 Ω square −1 from silicon carbide films on Si wafers with highly enhanced surface area. The silicon carbide film acts as both a template and source of graphitic carbon, while, simultaneously, the nickel induces porosity on the surface of the film by forming silicides during the annealing process which are subsequently removed. As stand-alone electrodes in supercapacitors, these transfer-free graphene-on-chip samples show a typical double-layer supercapacitive behaviour with gravimetric capacitance of up to 65 F g −1 . This work is the first attempt to produce graphene with high surface area from silicon carbide thin films for energy storage at the wafer-level and may open numerous opportunities for on-chip integrated energy storage applications. (paper)

Direct electron transfer of hemoglobin in a CdS nanorods and Nafion composite film on carbon ionic liquid electrode

International Nuclear Information System (INIS)

Sun Wei; Wang Dandan; Li Guicun; Zhai Ziqin; Zhao Ruijun; Jiao Kui

2008-01-01

In this paper the direct electron transfer of hemoglobin (Hb) was carefully investigated by using a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) modified carbon paste electrode (CILE) as the basal working electrode. Hb was immobilized on the surface of CILE with the nanocomposite film composed of Nafion and CdS nanorods by a step-by-step method. UV-vis and FT-IR spectra showed that Hb in the composite film remained its native structure. The direct electrochemical behaviors of Hb in the composite film were further studied in a pH 7.0 phosphate buffer solution (PBS). A pair of well-defined and quasi-reversible cyclic voltammetric peaks of Hb was obtained with the formal potential (E 0 ') at -0.295 V (vs. SCE), which was the characteristic of heme Fe(III)/Fe(II) redox couples. The direct electrochemistry of Hb was achieved on the modified electrode and the apparent heterogeneous electron transfer rate constant (k s ) was calculated to be 0.291 s -1 . The formal potentials of Hb Fe(III)/Fe(II) couple shifted negatively with the increase of buffer pH and a slope value of -45.1 mV/pH was got, which indicated that one electron transfer accompanied with one proton transportation. The fabricated Hb sensor showed good electrocatalytic manner to the reduction of trichloroacetic acid (TCA)

Interactions of the spin-labeled chloroethylnitrosourea SLCNUgly with electrode-supported lipid films

International Nuclear Information System (INIS)

Tacheva, Bilyana; Georgieva, Radostina; Karabaliev, Miroslav

2016-01-01

The spin-labeled chloroethylnitrosourea containig glycine SLCNUgly is an analogue of the clinically used nitrosourea drug lomustine (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, CCNU), showing promising properties and features in vitro as well as in vivo. In this work the interaction of SLCNUgly with a lipid model membrane is investigated. The presented results indicate penetration of the drug in the membranes without causing defects of the lipid structure and reveal the potential of both SLCNUgly and electrode-supported lipid films as models for investigating nitrosourea drugs-membrane interactions.

Development of the α-IGZO/Ag/α-IGZO Triple-Layer Structure Films for the Application of Transparent Electrode

Directory of Open Access Journals (Sweden)

Kun-Neng Chen

2017-02-01

Full Text Available We investigated the structural, optical, and electrical properties of amorphous IGZO/silver/amorphous IGZO (α-IGZO/Ag/α-IGZO triple-layer structures that were deposited at room temperature on Eagle XG glass and flexible polyethylene terephthalate substrates through the sputtering method. Thin Ag layers with different thicknesses were inserted between two IGZO layers to form a triple-layer structure. Ag was used because of its lower absorption and resistivity. Field emission scanning electron microscopy measurements of the triple-layer structures revealed that the thicknesses of the Ag layers ranged from 13 to 41 nm. The thickness of the Ag layer had a large effect on the electrical and optical properties of the electrodes. The optimum thickness of the Ag metal thin film could be evaluated according to the optical transmittance, electrical conductivity, and figure of merit of the electrode. This study demonstrates that the α-IGZO/Ag/α-IGZO triple-layer transparent electrode can be fabricated with low sheet resistance (4.2 Ω/□ and high optical transmittance (88.1% at room temperature without postannealing processing on the deposited thin films.

Investigations on the effects of electrode materials on the device characteristics of ferroelectric memory thin film transistors fabricated on flexible substrates

Science.gov (United States)

Yang, Ji-Hee; Yun, Da-Jeong; Seo, Gi-Ho; Kim, Seong-Min; Yoon, Myung-Han; Yoon, Sung-Min

2018-03-01

For flexible memory device applications, we propose memory thin-film transistors using an organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] gate insulator and an amorphous In-Ga-Zn-O (a-IGZO) active channel. The effects of electrode materials and their deposition methods on the characteristics of memory devices exploiting the ferroelectric field effect were investigated for the proposed ferroelectric memory thin-film transistors (Fe-MTFTs) at flat and bending states. It was found that the plasma-induced sputtering deposition and mechanical brittleness of the indium-tin oxide (ITO) markedly degraded the ferroelectric-field-effect-driven memory window and bending characteristics of the Fe-MTFTs. The replacement of ITO electrodes with metal aluminum (Al) electrodes prepared by plasma-free thermal evaporation greatly enhanced the memory device characteristics even under bending conditions owing to their mechanical ductility. Furthermore, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) was introduced to achieve robust bending performance under extreme mechanical stress. The Fe-MTFTs using PEDOT:PSS source/drain electrodes were successfully fabricated and showed the potential for use as flexible memory devices. The suitable choice of electrode materials employed for the Fe-MTFTs is concluded to be one of the most important control parameters for highly functional flexible Fe-MTFTs.

Highly flexible self-standing film electrode composed of mesoporous rutile TiO2/C nanofibers for lithium-ion batteries

International Nuclear Information System (INIS)

Zhao Bote; Cai Rui; Jiang Simin; Sha Yujing; Shao Zongping

2012-01-01

There is increasing interest in flexible, safe, high-power thin-film lithium-ion batteries which can be applied to various modern devices. Although TiO 2 in rutile phase is highly attractive as an anode material of lithium-ion batteries for its high thermal stability and theoretical capacity of 336 mA h g −1 and low price, its inflexibility and sluggish lithium intercalation kinetics of bulk phase strongly limit its practical application for particular in thin-film electrode. Here we show a simple way to prepare highly flexible self-standing thin-film electrodes composed of mesoporous rutile TiO 2 /C nanofibers with low carbon content ( 2 in as-fabricated nanofibers. Big size (10 cm × 4 cm), flexible thin film is obtained after heat treatment under 10%H 2 –Ar at 900 °C for 3 h. After optimization, the diameter of fibers can reach as small as ∼110 nm, and the as-prepared rutile TiO 2 films show high initial electrochemical activity with the first discharge capacity as high as 388 mA h g −1 . What is more, very stable reversible capacities of ∼122, 92, and 70 mA h g −1 are achieved respectively at 1, 5 and 10 C rates with negligible decay rate within 100 cycling times.

Process development of ITO source/drain electrode for the top-gate indium-gallium-zinc oxide transparent thin-film transistor

International Nuclear Information System (INIS)

Cheong, Woo-Seok; Yoon, Young-sun; Shin, Jae-Heon; Hwang, Chi-Sun; Chu, Hye Yong

2009-01-01

Indium-tin oxide (ITO) has been widely used as electrodes for LCDs and OLEDs. The applications are expanding to the transparent thin-film transistors (TTFT S ) for the versatile circuits or transparent displays. This paper is related with optimization of ITO source and drain electrode for TTFTs on glass substrates. For example, un-etched ITO remnants, which frequently found in the wet etching process, often originate from unsuitable ITO formation processes. In order to improve them, an ion beam deposition method is introduced, which uses for forming a seed layer before the main ITO deposition. We confirm that ITO films with seed layers are effective to obtain clean and smooth glass surfaces without un-etched ITO remnants, resulting in a good long-run electrical stability of the top-gate indium-gallium-zinc oxide-TTFT.

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure and properties of PZT thin films on strontium ruthenate and calcium ruthenate electrodes

International Nuclear Information System (INIS)

Wu, T.-J.; Tsai, D.-S.

2004-01-01

PZT thin films have been prepared via metalorganic CVD (MOCVD) on four substrates of conducting oxides of ruthenates, SrRuO 3 /Pt/Ti/SiO 2 /Si(1 0 0), SrRuO 3 /SiO 2 /Si(1 0 0), CaRuO 3 /Pt/Ti/SiO 2 /Si(1 0 0), CaRuO 3 /SiO 2 /Si(1 0 0). The conducting ruthenate layers were also grown using MOCVD. Ferroelectric properties of polarization fatigue and leakage current density are measured. The internal strain of PZT thin crystal which is mainly constrained by the bottom electrode seems to be the decisive factor in ferroelectric properties. The internal strain of PZT is represented by its tetragonality ratio. The PZT thin film in the capacitor Au/PZT/SrRuO 3 /Pt/Ti/SiO 2 /Si, with the largest tetragonality ratio 1.026, exhibits an optimum combination of large polarization, less fatigue, and low leakage current density. Both SrRuO 3 and CaRuO 3 are good diffusion barriers to prevent interdiffusion of cations between the ferroelectric and the electrode. The slightly higher intermixing at the CaRuO 3 -to-Pt/Ti interface is owing to the high annealing temperature needed in CaRuO 3 synthesis

Solid-state electrochemiluminescence sensor through the electrodeposition of Ru(bpy){sub 3}{sup 2+}/AuNPs/chitosan composite film onto electrode

Energy Technology Data Exchange (ETDEWEB)

Yun Wen; Xu Ying; Dong Ping; Ma Xiongxiong [Department of Chemistry, East China Normal University, ZhongShan Road North 3663, Shanghai 20062 (China); He Pingang [Department of Chemistry, East China Normal University, ZhongShan Road North 3663, Shanghai 20062 (China)], E-mail: pghe@chem.ecnu.edu.cn; Fang Yuzhi [Department of Chemistry, East China Normal University, ZhongShan Road North 3663, Shanghai 20062 (China)], E-mail: yuzhi@online.sh.cn

2009-03-02

Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy){sub 3}{sup 2+}) has been successfully immobilized onto electrode through the electrodeposition of Ru(bpy){sub 3}{sup 2+}/AuNPs/chitosan composite film. In the experiments, chitosan solution was first mixed with Au nanoparticles (AuNPs) and Ru(bpy){sub 3}{sup 2+}. Then, during chronopotentiometry experiments in this mixed solution, a porous 3D network structured film containing Ru(bpy){sub 3}{sup 2+}, AuNPs and chitosan has been electrodeposited onto cathode due to the deposition of chitosan when pH value is over its pK{sub a} (6.3). The applied current density is crucial to the film thickness and the amount of the entrapped Ru(bpy){sub 3}{sup 2+}. Additionally, these doping Ru(bpy){sub 3}{sup 2+} in the composite film maintained their intrinsic electrochemical and electrochemiluminescence activities. Consequently, this Ru(bpy){sub 3}{sup 2+}/AuNPs/chitosan modified electrode has been used in ECL to detect tripropylamine, and the detection limit was 5 x 10{sup -10} M.

Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

Science.gov (United States)

Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

2015-02-01

Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

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

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......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...... of the film outside, near and inside a dark ring induced by a voltage applied to another probe and found the resistivity to be directly related to the observed absorbance of the film. The standard electrochromic mechanism of ion insertion was used to explain the observations. We anticipate this experimental...

Chronopotentiometric stripping analysis of selenium using mercury film electrode

Directory of Open Access Journals (Sweden)

Suturović Zvonimir J.

2002-01-01

Full Text Available The influence of the most important experimental factors in chronopotentiometric stripping analysis (CSA of selenium( IV using mercury film working electrode was examined. Interferences of copper, iron and lead were investigated as well. The possibility of avoiding prolonged deaeration of the solution was examined by applying medium exchange modification of the technique, where the dissolution of the deposit was performed in calcium-chloride solution. Detection limits obtained for the modification of the CSA with prior deaeration and medium exchange modification were 0.4 μg/dmJ and 1.15μg/dmJ, respectively. Accuracy of the defined techniques has been confirmed by analysing reference material (RM 8436 -wheat durum flour. The results obtained by applying both modifications of the technique showed a very good agreement of total selenium content with declareted value.

Effect of Source/Drain Electrodes on the Electrical Properties of Silicon–Tin Oxide Thin-Film Transistors

Directory of Open Access Journals (Sweden)

Xianzhe Liu

2018-05-01

Full Text Available Ultra-high definition displays have become a trend for the current flat plane displays. In this study, the contact properties of amorphous silicon–tin oxide thin-film transistors (a-STO TFTs employed with source/drain (S/D electrodes were analyzed. Ohmic contact with a good device performance was achieved when a-STO was matched with indium-tin-oxide (ITO or Mo electrodes. The acceptor-like densities of trap states (DOS of a-STO TFTs were further investigated by using low-frequency capacitance–voltage (C–V characteristics to understand the impact of the electrode on the device performance. The reason of the distinct electrical performances of the devices with ITO and Mo contacts was attributed to different DOS caused by the generation of local defect states near the electrodes, which distorted the electric field distribution and formed an electrical potential barrier hindering the flow of electrons. It is of significant importance for circuit designers to design reliable integrated circuits with SnO2-based devices applied in flat panel displays.

Amperometric sensing of NADH and ethanol using a hybrid film electrode modified with electrochemically fabricated zirconia nanotubes and poly (acid fuchsin)

International Nuclear Information System (INIS)

Liu, X.; Li, B.; Zhan, G.; Liu, C.; Li, C.; Ma, M.

2012-01-01

We report on a glassy carbon electrode (GCE) modified with a film of chitosin containing acid fuchsin (AF) adsorbed onto zirconia nanotubes. The mixture was polymerized by cyclic voltammetric scannings in the potential range from - 0. 8 V to +1. 3 V in buffer solution to produce a hybrid film electrode (nano-ZrO 2 /PAF/GCE). The morphology of the hybrid film electrode surface was characterized by scanning electron microscopy. Its electrochemical properties were studied via electrochemical impedance spectroscopy. The electrochemical response of nicotinamide adenine dinucleotide (NADH) was investigated by differential pulse voltammetry and amperometry. The results indicated that the nano-ZrO 2 /PAF/GCE possesses well synergistic catalytic activity towards NADH. Compared to an unmodified GCE, the oxidation overpotential is negatively shifted by 224 mV, and the oxidation current is significantly increased. Under optimal conditions, the amperometric response is linearly proportional to the concentration of NADH in the 1. 0 - 100. 0 μM concentration range. Ethanol also can be determined by amperometry if alcohol dehydrogenase and NADH are added to the sample. Two linear relationships between current and alcohol concentration were obtained. They cover the range from 0. 03 to 1. 0 mM, and from 1. 0 to 12. 0 mM. (author)

Improved stability of titanium based boron-doped chemical vapor deposited diamond thin-film electrode by modifying titanium substrate surface

International Nuclear Information System (INIS)

Lim, P.Y.; Lin, F.Y.; Shih, H.C.; Ralchenko, V.G.; Varnin, V.P.; Pleskov, Yu.V.; Hsu, S.F.; Chou, S.S.; Hsu, P.L.

2008-01-01

The film quality and electrochemical properties of BDD (boron-doped diamond) thin films grown by hot-filament chemical vapor deposition technique on titanium substrates that had been subjected to a range of pre-treatment processes were evaluated. The pre-roughened Ti-substrates are shown to support more adherent BDD films. It is evident that acid-etching the Ti-substrate involves surface hydrogenation that enhances nucleation and formation of diamond thereon. The prepared BDD film exhibits wide potential window and electrochemical reversibility. It also demonstrated a better long-term electrochemical stability based on the low variation in voltametric background current upon the exposing of the electrodes to repeated cycles of electrochemical metal deposition/stripping process

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.

Electrochemical and spectroelectrochemical characterization of different mesoporous TiO2 film electrodes for the immobilization of Cytochrome c

Science.gov (United States)

Katsiaounis, Stavros; Tiflidis, Christina; Tsekoura, Christina; Topoglidis, Emmanuel

2018-03-01

In this work three different mesoporous TiO2 film electrodes were prepared and used for the immobilization of Cytochrome c (Cyt-c). Films prepared via a standard sol-gel route (SG-films) were compared with commercially available benchmark nanotitania materials, namely P25 Degussa (P25-films) and Dyesol nanopaste (Dyesol films). Their properties, film deposition characteristics and their abilities to adsorb protein molecules in a stable and functional way were examined. We investigated whether it is possible, rather than preparing TiO2 films using multistep, lengthy and not always reproducible sol-gel procedures, to use commercially available nanotitania materials and produce reproducible films faster that exhibit all the properties that make TiO2 films ideal for protein immobilization. Although these materials are formulated primarily for dye-sensitized solar cell applications, in this study we found out that protein immobilization is facile and remarkably stable on all of them. We also investigated their electrochemical properties by using cyclic voltammetry and spectroelectrochemistry and found out that not only direct reduction of Fe(III)-heme to Fe(II)-heme of immobilized Cyt-c was possible on all films but that the adsorbed protein remained electroactive.

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...

Energy harvesting using ionic electro-active polymer thin films with Ag-based electrodes

International Nuclear Information System (INIS)

Anand, S V; Arvind, K; Bharath, P; Roy Mahapatra, D

2010-01-01

In this paper we employ the phenomenon of bending deformation induced transport of cations via the polymer chains in the thickness direction of an electro-active polymer (EAP)–metal composite thin film for mechanical energy harvesting. While EAPs have been applied in the past in actuators and artificial muscles, promising applications of such materials in hydrodynamic and vibratory energy harvesting are reported in this paper. For this, functionalization of EAPs with metal electrodes is the key factor in improving the energy harvesting efficiency. Unlike Pt-based electrodes, Ag-based electrodes have been deposited on an EAP membrane made of Nafion. The developed ionic metal polymer composite (IPMC) membrane is subjected to a dynamic bending load, hydrodynamically, and evaluated for the voltage generated against an external electrical load. An increase of a few orders of magnitude has been observed in the harvested energy density and power density in air, deionized water and in electrolyte solutions with varying concentrations of sodium chloride (NaCl) as compared to Pt-based IPMC performances reported in the published literature. This will have potential applications in hydrodynamic and residual environmental energy harvesting to power sensors and actuators based on micro-and nano-electro-mechanical systems (MEMS and NEMS) for biomedical, aerospace and oceanic applications

LabVIEW-based sequential-injection analysis system for the determination of trace metals by square-wave anodic and adsorptive stripping voltammetry on mercury-film electrodes.

Science.gov (United States)

Economou, Anastasios; Voulgaropoulos, Anastasios

2003-01-01

The development of a dedicated automated sequential-injection analysis apparatus for anodic stripping voltammetry (ASV) and adsorptive stripping voltammetry (AdSV) is reported. The instrument comprised a peristaltic pump, a multiposition selector valve and a home-made potentiostat and used a mercury-film electrode as the working electrodes in a thin-layer electrochemical detector. Programming of the experimental sequence was performed in LabVIEW 5.1. The sequence of operations included formation of the mercury film, electrolytic or adsorptive accumulation of the analyte on the electrode surface, recording of the voltammetric current-potential response, and cleaning of the electrode. The stripping step was carried out by applying a square-wave (SW) potential-time excitation signal to the working electrode. The instrument allowed unattended operation since multiple-step sequences could be readily implemented through the purpose-built software. The utility of the analyser was tested for the determination of copper(II), cadmium(II), lead(II) and zinc(II) by SWASV and of nickel(II), cobalt(II) and uranium(VI) by SWAdSV.

Materials science and integration bases for fabrication of (BaxSr1-x)TiO3 thin film capacitors with layered Cu-based electrodes

Science.gov (United States)

Fan, W.; Kabius, B.; Hiller, J. M.; Saha, S.; Carlisle, J. A.; Auciello, O.; Chang, R. P. H.; Ramesh, R.

2003-11-01

The synthesis and fundamental material properties of layered TiAl/Cu/Ta electrodes were investigated to achieve the integration of Cu electrodes with high-dielectric constant (κ) oxide thin films for application to the fabrication of high-frequency devices. The Ta layer is an excellent diffusion barrier to inhibit deleterious Cu diffusion into the Si substrate, while the TiAl layer provides an excellent barrier against oxygen diffusion into the Cu layer to inhibit Cu oxidation during the growth of the high-κ layer in an oxygen atmosphere. Polycrystalline (BaxSr1-x)TiO3 (BST) thin films were grown on the Cu-based bottom electrode by rf magnetron sputtering at temperatures in the range 400-600 °C in oxygen, to investigate the performance of BST/Cu-based capacitors. Characterization of the Cu-based layered structure using surface analytical methods showed that two amorphous oxide layers were formed on both sides of the TiAl barrier, such that the oxide layer on the free surface of the TiAl layer correlates with TiAlOx, while the oxide layer at the TiAl/Cu interface is an Al2O3-rich layer. This double amorphous barrier layer structure effectively prevents oxygen penetration towards the underlying Cu and Ta layers. The TiAlOx interfacial layer, which has a relatively low dielectric constant compared with BST, reduced the total capacitance of the BST thin film capacitors. In addition, the layered electrode-oxide interface roughening observed during the growth of BST films at high temperature, due to copper grain growth, resulted in large dielectric loss on the fabricated BST capacitors. These problems were solved by growing the BST layer at 450 °C followed by a rapid thermal annealing at 700 °C. This process significantly reduced the thickness of the TiAlOx layer and interface roughness resulting in BST capacitors exhibiting properties suitable for the fabrication of high-performance high-frequency devices. In summary, relatively high dielectric constant (280), low

Materials science and integration bases for fabrication of (BaxSr1-x)TiO3 thin film capacitors with layered Cu-based electrodes

International Nuclear Information System (INIS)

Fan, W.; Kabius, B.; Hiller, J.M.; Saha, S.; Carlisle, J.A.; Auciello, O.; Chang, R.P.H.; Ramesh, R.

2003-01-01

The synthesis and fundamental material properties of layered TiAl/Cu/Ta electrodes were investigated to achieve the integration of Cu electrodes with high-dielectric constant (κ) oxide thin films for application to the fabrication of high-frequency devices. The Ta layer is an excellent diffusion barrier to inhibit deleterious Cu diffusion into the Si substrate, while the TiAl layer provides an excellent barrier against oxygen diffusion into the Cu layer to inhibit Cu oxidation during the growth of the high-κ layer in an oxygen atmosphere. Polycrystalline (Ba x Sr 1-x )TiO 3 (BST) thin films were grown on the Cu-based bottom electrode by rf magnetron sputtering at temperatures in the range 400-600 deg. C in oxygen, to investigate the performance of BST/Cu-based capacitors. Characterization of the Cu-based layered structure using surface analytical methods showed that two amorphous oxide layers were formed on both sides of the TiAl barrier, such that the oxide layer on the free surface of the TiAl layer correlates with TiAlO x , while the oxide layer at the TiAl/Cu interface is an Al 2 O 3 -rich layer. This double amorphous barrier layer structure effectively prevents oxygen penetration towards the underlying Cu and Ta layers. The TiAlO x interfacial layer, which has a relatively low dielectric constant compared with BST, reduced the total capacitance of the BST thin film capacitors. In addition, the layered electrode-oxide interface roughening observed during the growth of BST films at high temperature, due to copper grain growth, resulted in large dielectric loss on the fabricated BST capacitors. These problems were solved by growing the BST layer at 450 deg. C followed by a rapid thermal annealing at 700 deg. C. This process significantly reduced the thickness of the TiAlO x layer and interface roughness resulting in BST capacitors exhibiting properties suitable for the fabrication of high-performance high-frequency devices. In summary, relatively high

Integrated fast assembly of free-standing lithium titanate/carbon nanotube/cellulose nanofiber hybrid network film as flexible paper-electrode for lithium-ion batteries.

Science.gov (United States)

Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Xue, Xin; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

2015-05-27

A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphene-based transparent electrodes for hybrid solar cells

Directory of Open Access Journals (Sweden)

Pengfei eLi

2014-11-01

Full Text Available The graphene-based transparent and conductive films were demonstrated to be cost-effective electrodes working in organic-inorganic hybrid Schottky solar cells. Large area graphene films were produced by chemical vapor deposition (CVD on copper foils and transferred onto glass as transparent electrodes. The hybrid solar cell devices consist of solution processed poly (3, 4-ethlenedioxythiophene: poly (styrenesulfonate (PEDOT: PSS which is sandwiched between silicon wafer and graphene electrode. The solar cells based on graphene electrodes, especially those doped with HNO3, has comparable performance to the reference devices using commercial indium tin oxide (ITO. Our work suggests that graphene-based transparent electrode is a promising candidate to replace ITO.

Amperometric bienzyme glucose biosensor based on carbon nanotube modified electrode with electropolymerized poly(toluidine blue O) film

International Nuclear Information System (INIS)

Wang Wenju; Wang Fang; Yao Yanli; Hu Shengshui; Shiu, Kwok-Keung

2010-01-01

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 2 O 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 2 O 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 -1 cm -2 at an applied potential of -0.10 V in air-saturated electrolytes.

Preparation of polypyrrole/ferrocyanide films modified carbon paste electrode and its application on the electrocatalytic determination of ascorbic acid

Energy Technology Data Exchange (ETDEWEB)

Raoof, Jahan-Bakhsh; Ojani, Reza; Rashid-Nadimi, Sahar

2004-01-15

Functionalized polypyrrole film were prepared by incorporation of (Fe(CN){sub 6}){sup 4-} as doping anion, during the electropolymerization of pyrrole onto a carbon paste electrode (CPE) in aqueous solution by using potentiostatic method. The electrochemical behavior of the (Fe(CN){sub 6}){sup 3-}/(Fe(CN){sub 6}){sup 4-} redox couple in polypyrrole was studied by cyclic voltammetry and double step potential chronoamperometry methods. In this study, an obvious surface redox reaction was observed and dependence of this reaction on the solution pH was illustrated. The electrocatalytic ability of polypyrrole/ferrocyanide films modified carbon paste electrode (Ppy/FCNMCPEs) was demonstrated by oxidation of ascorbic acid. It has been found that under optimum condition (pH 7.00), the oxidation of ascorbic acid at the surface of such electrode occurs at a potential about 540 mV less positive than unmodified carbon paste electrode. The kinetic parameters such as electron transfer coefficient, {alpha} and catalytic reaction rate constant, k{sub h}', were also determined by using various electrochemical approaches. The catalytic oxidation peak current showed a linear dependent on the ascorbic acid concentration and a linear calibration curve was obtained in the range of 4.5x10{sup -4} to 9.62x10{sup -3} M of ascorbic acid with a correlation coefficient of 0.9999. The detection limit (2{sigma}) was determined as 5.82x10{sup -5} M.

Fractals in several electrode materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunyong, E-mail: zhangchy@njau.edu.cn [Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Suzhou Key Laboratory of Environment and Biosafety, Suzhou Academy of Southeast University, Dushuhu lake higher education town, Suzhou 215123 (China); Wu, Jingyu [Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Fu, Degang [Suzhou Key Laboratory of Environment and Biosafety, Suzhou Academy of Southeast University, Dushuhu lake higher education town, Suzhou 215123 (China); State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)

2014-09-15

Highlights: • Fractal geometry was employed to characterize three important electrode materials. • The surfaces of all studied electrodes were proved to be very rough. • The fractal dimensions of BDD and ACF were scale dependent. • MMO film was more uniform than BDD and ACF in terms of fractal structures. - Abstract: In the present paper, the fractal properties of boron-doped diamond (BDD), mixed metal oxide (MMO) and activated carbon fiber (ACF) electrode have been studied by SEM imaging at different scales. Three materials are self-similar with mean fractal dimension in the range of 2.6–2.8, confirming that they all exhibit very rough surfaces. Specifically, it is found that MMO film is more uniform in terms of fractal structure than BDD and ACF. As a result, the intriguing characteristics make these electrodes as ideal candidates for high-performance decontamination processes.

Potentiometric sulfite biosensor based on entrapment of sulfite oxidase in a polypyrrole film on a platinum electrode modified with platinum nanoparticles

International Nuclear Information System (INIS)

Adeloju, Samuel B.; Hussain, Shahid

2016-01-01

The surface of a platinum electrode has been modified with platinum nanoparticles (PtNPs) and the enzyme sulfite oxidase (SOx), was entrapped on its surface in an ultrathin polypyrrole (PPy) film. The PtNPs, with a diameter of 30-40 nm, were deposited on the Pt electrode by cycling the electrode potential 20 times from -200 to 200 mV at a sweep rate of 50 mV.s"-"1. Morphological evidence of the successful incorporation of SOx and the presence of PtNPs were obtained by scanning electron microscopy. Also, the electrochemical behavior of the PtNPs/PPy-SOx film was examined by cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy and potentiometry. Under optimized conditions, the biosensor achieved a sensitivity of 57.5 mV.decade"-"1, a linear response that extends from 0.75 to 65 μM of sulfite, a detection limit of 12.4 nM, and a response time of 3-5 s. The biosensor was successfully applied to the determination of sulfite in wine and beer samples. (author)

Fabrication of conducting polymer-gold nanoparticles film on electrodes using monolayer protected gold nanoparticles and its electrocatalytic application

Energy Technology Data Exchange (ETDEWEB)

Kannan, Palanisamy [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India); School of Chemical and Biomedical Engineering, N1.3, B4-01, 70 Nanyang Drive, Nanyang Technological University, Singapore 637457 (Singapore); John, S. Abraham, E-mail: abrajohn@yahoo.co.in [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India)

2011-08-01

We wish to report a simple and new strategy for the fabrication of gold nanoparticles-conducting polymer film on glassy carbon (GC) and indium tin oxide (ITO) surfaces using 5-amino-2-mercapto-1,3,4-thiadiazole capped gold nanoparticles (AMT-AuNPs) in 0.01 M H{sub 2}SO{sub 4} by electropolymerization. The presence of amine groups on the surface of the AuNPs was responsible for the deposition of the AMT-AuNPs film on the electrode surface. The atomic force microscopy (AFM) studies reveal that the fabricated p-AMT-AuNPs film showed homogeneously distributed AuNPs with a spherical shape of {approx}8 nm diameter. The XPS spectrum shows the binding energies at 83.8 and 87.5 eV in the Au 4f region corresponding to 4f{sub 7/2} and 4f{sub 5/2}, respectively. The position and difference between these two peaks (3.7 eV) exactly match the value reported for Au{sup 0}. The N1s XPS showed three binding energies at 396.7, 399.6 and 403.3 eV, corresponding to the =NH, -NH- and -N{sup +}H-, respectively, confirming that the electropolymerization proceeded through the oxidation of -NH{sub 2} groups present on the periphery of the AMT-AuNPs. The application of the present p-AMT-AuNPs modified electrode was demonstrated by studying the electro reduction of oxygen at pH 7.2. The p-AMT-AuNPs film enhanced the oxygen reduction current more than three times than that of p-AMT film prepared under identical conditions.

Fabrication and characterization of p{sup +}-i-p{sup +} type organic thin film transistors with electrodes of highly doped polymer

Energy Technology Data Exchange (ETDEWEB)

Tadaki, Daisuke [Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579 (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Ma, Teng; Niwano, Michio, E-mail: niwano@riec.tohoku.ac.jp [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Zhang, Jinyu; Iino, Shohei [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Hirano-Iwata, Ayumi [Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Kimura, Yasuo [CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Tokyo University of Technology, Hachioji, Tokyo 192-0982 (Japan); Rosenberg, Richard A. [Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439 (United States)

2016-04-21

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{sup +}-i-p{sup +} 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{sup +}) P3HT is used as the source and drain electrodes. The 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F{sub 4}-TCNQ) was used as the p-type dopant. A fabricating method of p{sup +}-i-p{sup +} OTFTs has been developed by using SiO{sub 2} and aluminum films as capping layers for micro-scaled patterning of the p{sup +}-P3HT electrodes. The characteristics of the OTFTs were examined using the photoelectron spectroscopy and electrical measurements. We demonstrated that the fabricated p{sup +}-i-p{sup +} OTFTs work with carrier injection through a built-in potential at p{sup +}/i interfaces. We found that the p{sup +}-i-p{sup +} 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{sup +}-P3HT layers.

AZO/Au/AZO tri-layer thin films for the very low resistivity transparent electrode applications

Energy Technology Data Exchange (ETDEWEB)

Chu, Chien-Hsun [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wu, Hung-Wei, E-mail: hwwu@mail.ksu.edu.tw [Department of Computer and Communication, Kun Shan University, Tainan 71003, Taiwan (China); Huang, Jow-Lay [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 70101, Taiwan (China)

2014-08-01

Highlights: • High-quality Al-doped ZnO (AZO)/Au/AZO transparent conducting oxide films. • AZO films (30 nm) made by RF sputtering; ion sputtering for Au film (5–20 nm). • Effects of Au thickness on optical and electrical properties were analyzed. • The resistivity of 9 × 10{sup −5} Ω cm and the transmittance of 86.2% of the multilayer films were obtained in this study. - Abstract: Aluminum-doped ZnO (AZO)/gold/AZO tri-layer structures with very low resistivity and high transmittance are prepared by simultaneous RF magnetron sputtering (for AZO) and ion sputtering (for Au). The properties of the tri-layer films are investigated at different Au layer thicknesses (5–20 nm). The effects of Au layer thickness and the role of Au on the transmission properties of the tri-layer films were investigated. The very low resistivity of 1.01 × 10{sup −5} Ω cm, mobility of 27.665 cm{sup 2} V{sup −1} s{sup −1}, and carrier concentration of 4.563 × 10{sup 22} cm{sup −3} were obtained at an Au layer thickness of 20 nm. The peak transmittance of 86.18% at 650-nm wavelength was obtained at an Au layer thickness of 8 nm. These results show the films to be a good candidate for high-quality electrode scheme in various display applications.

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

International Nuclear Information System (INIS)

Kurogi, H.; Yamagata, Y.; Ebihara, K.

1998-01-01

Pb(Zr X Ti 1-X )O 3 (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, λ=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm -2 on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P r =15 μC cm -2 , 30 μC cm -2 and E c =200 kV cm -1 , 100 kV cm -1 for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10 8 cycles of switching. (orig.)

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

Sculptured platinum nanowire counter electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyeonseok [Department of Electrical Engineering, Pennsylvania State University, University Park 16802 (United States); Horn, Mark W., E-mail: MHorn@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park 16802-6812 (United States)

2013-07-01

Sculptured platinum nanowire thin films were formed by oblique angle electron beam evaporation with a 5° vapor incidence angle and incorporated as counter electrodes for dye-sensitized solar cells (DSSCs). For the comparison of the performance, bare fluorine doped tin oxide, planar Pt electrodes and counter electrodes treated with chloroplatinic acid were prepared. The sculptured Pt nanowire electrodes showed five times lower charge transfer resistance (0.121 [Ω∗cm{sup 2}]) than that of Pt planar electrode (0.578 [Ω∗cm{sup 2}]) and when the Pt nanowire electrodes are treated with an H{sub 2}PtCl{sub 6} solution have more than ten times lower charge transfer resistance (0.04025 [Ω∗cm{sup 2}]). Moreover, Pt nanowire films used as a counter electrode lead to enhancement in current density and efficiency in comparison with Pt planar counter electrodes. The conversion efficiency with planar electrodes was 5.1 [%] while the efficiency of DSSC with platinum nanowire counter electrodes reached to 5.63 [%] under AM 1.5 illumination. - Highlights: • Pt sculptured thin films (STFs) fabricated by electron beam evaporator. • The STFs featured higher roughness and lower charge transfer resistance. • Improved performance of dye-sensitized solar cells by Pt STFs counter electrodes.

Low-temperature fabrication of TiO2 nanocrystalline film electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Shan, G.; Lee, K.E.; Charboneau, C.; Demopoulos, G.P.; Gauvin, R. [McGill Univ., Montreal, PQ (Canada). Dept. of Materials Engineering; Savadogo, O. [Ecole Polytechnique de Montreal, PQ (Canada). Dept. de Genie Chimique

2008-07-01

Dye-sensitized solar cells (DSSCs) have the potential to render solar energy widely accessible. The deposition of titania nano-crystalline powders on a substrate is an important step in the manufacture of the DSSC. The deposition forms a mesoporous thin film that is followed by thermal treatment and sensitization. Usually titania films are deposited on glass by screen printing and then annealed at temperatures as high as 530 degrees C to provide a good electrical contact between the semiconductor particles and crystallization of the anatase phase. Several research and development efforts have focused on the deposition of titania film on flexible plastic substrates that will simplify the whole manufacturing process in terms of flexibility, weight, application and cost. Lower temperature processing is needed for the preparation of plastic-based titania film electrodes, but this has proven to be counterproductive when it comes to the cell's conversion efficiency. This paper presented a comprehensive evaluation of the different coating and annealing techniques at low temperature as well as important processing factors for improvement. To date, these techniques include pressing, hydrothermal process, electrodeposition, electrophoretic deposition, microwave or UV irradiation, and lift-off technique.

pH sensing in aqueous solutions using a MnO2 thin film electrodeposited on a glassy carbon electrode

International Nuclear Information System (INIS)

Cherchour, N.; Deslouis, C.; Messaoudi, B.; Pailleret, A.

2011-01-01

An electrolysis technique at a constant potential was used to develop a highly reproducible and fast elaboration method of adherent manganese dioxide thin films on a glassy carbon electrode from aqueous solutions containing sulfuric acid and manganese sulfate. The resulting films were found to have a nanostructured character presumably due rather to birnessite (δ-MnO 2 ) than to γ-MnO 2 , as suggested by their Raman and XRD signatures. They lead to modified electrodes that present an obvious although complex pH dependent potentiometric response. This sensor indeed showed a single slope non-Nernstian linear behaviour over the 1.5-12 pH range for increasing pH direction ('trace'), whereas a Nernstian two slopes linear behaviour was observed for decreasing pH direction ('re-trace'). Preliminary EIS experiments carried out at a pH value of 1.8 seem to reveal a sensitivity mechanism based on proton insertion process at least at highly acidic pH values.

Composite carbon foam electrode

Science.gov (United States)

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

1997-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

Cyclic Voltammetric Investigation of Dopamine at Poly-(Gabapentin Modified Carbon Paste Electrode

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M. T. Shreenivas

2011-01-01

Full Text Available The poly (gabapentin film was prepared on the surface of carbon paste electrode by electrochemical method using cyclic voltammetric technique. The poly (gabapentin film-modified carbon paste electrode was calibrated with standard potassium ferrocyanide solution in 1 M KCl as a supporting electrolyte. The prepared poly (gabapentin film-coated electrode exhibits excellent electrocatalytic activity towards the detection of dopamine at physiological pH. The scan rate effect was found to be diffusion-controlled electrode process. The concentration effect of dopamine was studied, and the redox peak potentials of dopamine were dependant on pH.

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

Energy Technology Data Exchange (ETDEWEB)

Kurogi, H; Yamagata, Y; Ebihara, K [Kumamoto Univ. (Japan). Dept. of Electr. Eng. and Comput. Sci.; Inoue, N [Kyushu Electric Power Co., Inc., Suizenji, 1-6-36, Kumamoto 862 (Japan)

1998-03-01

Pb(Zr{sub X}Ti{sub 1-X})O{sub 3} (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, {lambda}=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm{sup -2} on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P{sub r}=15 {mu}C cm{sup -2}, 30 {mu}C cm{sup -2} and E{sub c}=200 kV cm{sup -1}, 100 kV cm{sup -1} for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10{sup 8} cycles of switching. (orig.) 7 refs.

A molecular theory of chemically modified electrodes with self-assembled redox polyelectrolye thin films: Reversible cyclic voltammetry

Energy Technology Data Exchange (ETDEWEB)

Tagliazucchi, Mario; Calvo, Ernesto J. [INQUIMAE, DQIAyQF Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Szleifer, Igal [Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

2008-10-01

A molecular theory of chemically modified electrodes is applied to study redox polyelectroyte modified electrodes. The molecular approach explicitly includes the size, shape, charge distribution, and conformations of all of the molecular species in the system as well as the chemical equilibria (redox and acid-base) and intermolecular interactions. An osmium pyridine-bipyridine complex covalently bound to poly(allyl-amine) backbone (PAH-Os) adsorbed onto mercapto-propane sulfonate (MPS) thiolated gold electrode is described. The potential and electrolyte composition dependent redox and nonredox capacitance can be calculated with the molecular theory in very good agreement with voltammetric experiments under reversible conditions without the use of freely adjustable parameter. Unlike existing phenomenological models the theory links the electrochemical behavior with the structure of the polymer layer. The theory predicts a highly inhomogeneous distribution of acid-base and redox states that strongly couples with the spatial arrangement of the molecular species in the nanometric redox film. (author)

mwnts composite film modified glassy carbon electrode

African Journals Online (AJOL)

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ABSTRACT: A poly p-aminosalicylic acid (Poly(p-ASA)) and multiwall carbon nanotubes. (MWCNTs) composite modified glassy carbon (GC) electrode was constructed by casting the MWNTs on the GC electrode surface followed by electropolymerization of the p-ASA on the MWCNTs/GCE. The electrochemical behaviours ...

S Sensors: Fumarate-Based fcu-MOF Thin Film Grown on a Capacitive Interdigitated Electrode

KAUST Repository

Yassine, Omar

2016-10-31

Herein we report the fabrication of an advanced sensor for the detection of hydrogen sulfide (H2S) at room temperature, using thin films of rare-earth metal (RE)-based metal-organic framework (MOF) with underlying fcu topology. This unique MOF-based sensor is made via the insitu growth of fumarate-based fcu-MOF (fum-fcu-MOF) thin film on a capacitive interdigitated electrode. The sensor showed a remarkable detection sensitivity for H2S at concentrations down to 100ppb, with the lower detection limit around 5ppb. The fum-fcu-MOF sensor exhibits a highly desirable detection selectivity towards H2S vs. CH4, NO2, H2, and C7H8 as well as an outstanding H2S sensing stability as compared to other reported MOFs. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of biomembrane-like films on carbon electrodes using alkanethiol and diazonium salt and their application for direct electrochemistry of myoglobin.

Science.gov (United States)

Anjum, Saima; Qi, Wenjing; Gao, Wenyue; Zhao, Jianming; Hanif, Saima; Aziz-Ur-Rehman; Xu, Guobao

2015-03-15

Alkanethiols generally form self-assembled monolayers on gold electrodes and the electrochemical reduction of aromatic diazonium salts is a popular method for the covalent modification of carbon. Based on the reaction of alkanethiol with aldehyde groups covalently bound on carbon surface by the electrochemical reduction of aromatic diazonium salts, a new strategy for the modification of carbon electrodes with alkanethiols has been developed. The modification of carbon surface with aldehyde groups is achieved by the electrochemical reduction of aromatic diazonium salts in situ electrogenerated from a nitro precursor, p-nitrophenylaldehyde, in the presence of nitrous acid. By this way, in situ electrogenerated p-aminophenyl aldehyde from p-nitrophenylaldehyde immediately reacts with nitrous acid, effectively minimizing the side reaction of amine groups and aldehyde groups. The as-prepared alkanethiol-modified glassy carbon electrode was further used to make biomembrane-like films by casting didodecyldimethylammonium bromide on its surface. The biomembrane-like films enable the direct electrochemistry of immobilized myoglobin for the detection of hydrogen peroxide. The response is linear over the range of 1-600μM with a detection limit of 0.3μM. Copyright © 2014 Elsevier B.V. All rights reserved.

Electroencephalogram measurement using polymer-based dry microneedle electrode

Science.gov (United States)

Arai, Miyako; Nishinaka, Yuya; Miki, Norihisa

2015-06-01

In this paper, we report a successful electroencephalogram (EEG) measurement using polymer-based dry microneedle electrodes. The electrodes consist of needle-shaped substrates of SU-8, a silver film, and a nanoporous parylene protective film. Differently from conventional wet electrodes, microneedle electrodes do not require skin preparation and a conductive gel. SU-8 is superior as a structural material to poly(dimethylsiloxane) (PDMS; Dow Corning Toray Sylgard 184) in terms of hardness, which was used in our previous work, and facilitates the penetration of needles through the stratum corneum. SU-8 microneedles can be successfully inserted into the skin without breaking and could maintain a sufficiently low skin-electrode contact impedance for EEG measurement. The electrodes successfully measured EEG from the frontal pole, and the quality of acquired signals was verified to be as high as those obtained using commercially available wet electrodes without any skin preparation or a conductive gel. The electrodes are readily applicable to record brain activities for a long period with little stress involved in skin preparation to the users.

Electrocatalytic reduction of nitrite on tetraruthenated metalloporphyrins/Nafion glassy carbon modified electrode

Energy Technology Data Exchange (ETDEWEB)

Calfuman, Karla [Facultad de Ciencias, Departamento de Quimica, Universidad de Chile, Las Palmeras 3425, Casilla 653, Nunoa, Santiago (Chile); Aguirre, Maria Jesus [Facultad de Quimica y Biologia, Departamento de Quimica de los Materiales, Universidad de Santiago de Chile, Santiago (Chile); Canete-Rosales, Paulina; Bollo, Soledad [Facultad de Ciencias Quimicas y Farmaceuticas, Departamento de Quimica Farmacologica y Toxicologica, Universidad de Chile, Santiago (Chile); Llusar, Rosa [Departamento de Quimica Fisica y Analitica, Universidad de Jaume I, Castellon (Spain); Isaacs, Mauricio, E-mail: misaacs@uchile.cl [Facultad de Ciencias, Departamento de Quimica, Universidad de Chile, Las Palmeras 3425, Casilla 653, Nunoa, Santiago (Chile)

2011-10-01

Highlights: > Preparation and characterization of modified electrodes with M(II) Tetraruthenated porphyrins onto a Nafion film. > The electrodes were characterized by SEM, TEM, AFM and SECM techniques. > The modified electrodes are active in the electrochemical reduction of nitrite at -660 mV vs Ag/AgCl. > GC/Nf/CoTRP modified electrode is more electrochemically active than their Ni and Zn analogues. - Abstract: This paper describes the electrochemical reduction of nitrite ion in neutral aqueous solution mediated by tetraruthenated metalloporphyrins (Co(II), Ni(II) and Zn(II)) electrostatically assembled onto a Nafion film previously adsorbed on glassy carbon or ITO electrodes. Scanning electron microscope (SEM-EDX) and transmission electron microscopy (TEM) results have shown that on ITO electrodes the macrocycles forms multiple layers with a disordered stacking orientation over the Nafion film occupying hydrophobic and hydrophilic sites in the polyelectrolyte. Atomic force microscopy (AFM) results demonstrated that the Nafion film is 35 nm thick and tetraruthenated metalloporphyrins layers 190 nm thick presenting a thin but compacted morphology. Scanning electrochemical microscopy (SECM) images shows that the Co(II) tetraruthenated porphyrins/Nf/GC modified electrode is more electrochemically active than their Ni and Zn analogues. These modified electrodes are able to reduce nitrite at -660 mV showing enhanced reduction current and a decrease in the required overpotential compared to bare glassy carbon electrode. Controlled potential electrolysis experiments verify the production of ammonia, hydrazine and hydroxylamine at potentials where reduction of solvent is plausible demonstrating some selectivity toward the nitrite ion. Rotating disc electrode voltammetry shows that the factor that governs the kinetics of nitrite reduction is the charge propagation in the film.

3,5-Diamino-1,2,4-triazole@electrochemically reduced graphene oxide film modified electrode for the electrochemical determination of 4-nitrophenol

International Nuclear Information System (INIS)

Kumar, Deivasigamani Ranjith; Kesavan, Srinivasan; Baynosa, Marjorie Lara; Shim, Jae-Jin

2017-01-01

Highlights: •Triazole film was formed on electrochemically reduced graphene oxide. •pDAT@ERGO/GC was utilized for the electrochemical determination of 4-nitrophenol. •pDAT@ERGO/GC electrode offered wide concentration and nanomolar detection limit. •The fabricated electrode was employed in water sample analyses. -- Abstract: In this study, an eco-friendly benign method for the modification of electrochemically reduced graphene oxide (ERGO) on glassy carbon (GC) surface and electrochemical polymerized 3,5-diamino-1,2,4-triazole (DAT) film composite (pDAT@ERGO/GC) electrode was developed. The surface morphologies of the pDAT@ERGO/GC modified electrode were analyzed by field emission scanning electron microscopy (FESEM). FESEM images indicated that the ERGO supported pDAT has an almost homogeneous morphology structure with a size of 70 to 80 nm. It is due to the water oxidation reaction occurred while pDAT@ERGO/GC fabrication peak at +1.4 V leads to O 2 evolution and oxygen functional group functionalization on ERGO, which confirmed by X-ray photoelectron spectroscopy (XPS). In contrast, the bare GC modified with pDAT showed randomly arranged irregular bulky morphology structure compared to those of pDAT@ERGO/GC. Electrochemical reduction of graphene oxide was confirmed by Raman spectroscopy, XPS, and electrochemical impedance spectroscopy (EIS). The pDAT@ERGO/GC modified electrode was used for the electrochemical determination of 4-nitrophenol (4-NP). The 4-NP oxidation peak was observed at +0.25 V, and the differential pulse voltammetry demonstrated wide concentration range (5–1500 μM), high sensitivity (0.7113 μA μM −1 ), and low limit of detection (37 nM). Moreover, the pDAT@ERGO/GC electrode was applied to real water sample analysis by standard addition method, where in good recoveries (97.8% to 102.4%) were obtained.

Performance evaluation of symmetric supercapacitor based on cobalt hydroxide [Co(OH)2] thin film electrodes

International Nuclear Information System (INIS)

Jagadale, A.D.; Kumbhar, V.S.; Dhawale, D.S.; Lokhande, C.D.

2013-01-01

In the present investigation, we have successfully assembled symmetric supercapacitor device based on cobalt hydroxide [Co(OH) 2 ] thin film electrodes using 1 M KOH as an electrolyte. Initially, potentiodynamic electrodeposition method is employed for the preparation of Co(OH) 2 thin films onto stainless steel substrate. These films are characterized for structural and morphological elucidations using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD reveals formation of β-Co(OH) 2 material with hexagonal crystal structure. The SEM images show formation of nanoflakes like microstructure with average flake width 100 nm. Electrochemical characterizations of Co(OH) 2 based symmetric supercapacitor cell are carried out using cyclic voltammetry, charge–discharge and electrochemical impedance spectroscopy (EIS) techniques. In the performance evaluation the maximum values of specific capacitance, specific energy and specific power are encountered as 44 F g −1 , 3.96 Wh kg −1 and 42 kW kg −1 . The value of equivalent series resistance (ESR) is estimated as 2.3 Ω using EIS

A computation study on the interplay between surface morphology and electrochemical performance of patterned thin film electrodes for Li-ion batteries

Science.gov (United States)

Gur, Sourav; Frantziskonis, George N.; Aifantis, Katerina E.

2017-08-01

Recent experiments illustrate that the morphology of the electrode surface impacts the voltage - capacity curves and long term cycling performance of Li-ion batteries. The present study systematically explores the role of the electrode surface morphology and uncertainties in the reactions that occur during electrochemical cycling, by performing kinetic Monte Carlo (kMC) simulations using the lattice Boltzmann method (LBM). This allows encoding of the inherent stochasticity at discrete microscale reaction events over the deterministic mean field reaction dynamics that occur in Li-ion cells. The electrodes are taken to be dense thin films whose surfaces are patterned with conical, trapezoidal, dome-shaped, or pillar-shaped structures. It is shown that the inherent perturbations in the reactions together with the characteristics of the electrode surface configuration can significantly improve battery performance, mainly because patterned surfaces, as opposed to flat surfaces, result in a smaller voltage drop. The most efficient pattern was the trapezoidal, which is consistent with experimental evidence on Si patterned electrodes.

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.

A cost-effective nanoporous ultrathin film electrode based on nanoporous gold/IrO2 composite for proton exchange membrane water electrolysis

Science.gov (United States)

Zeng, Yachao; Guo, Xiaoqian; Shao, Zhigang; Yu, Hongmei; Song, Wei; Wang, Zhiqiang; Zhang, Hongjie; Yi, Baolian

2017-02-01

A cost-effective nanoporous ultrathin film (NPUF) electrode based on nanoporous gold (NPG)/IrO2 composite has been constructed for proton exchange membrane (PEM) water electrolysis. The electrode was fabricated by integrating IrO2 nanoparticles into NPG through a facile dealloying and thermal decomposition method. The NPUF electrode is featured in its 3D interconnected nanoporosity and ultrathin thickness. The nanoporous ultrathin architecture is binder-free and beneficial for improving electrochemical active surface area, enhancing mass transport and facilitating releasing of oxygen produced during water electrolysis. Serving as anode, a single cell performance of 1.728 V (@ 2 A cm-2) has been achieved by NPUF electrode with a loading of IrO2 and Au at 86.43 and 100.0 μg cm-2 respectively, the electrolysis voltage is 58 mV lower than that of conventional electrode with an Ir loading an order of magnitude higher. The electrolysis voltage kept relatively constant up to 300 h (@250 mA cm-2) during the course of durability test, manifesting that NPUF electrode is promising for gas evolution.

Comparison of physical and electrical properties of GZO/ZnO buffer layer and GZO as source and drain electrodes of α-IGZO thin-film transistors

Energy Technology Data Exchange (ETDEWEB)

Wu, Jia-Ling; Lin, Han-Yu; Su, Bo-Yuan; Chen, Yu-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Liu, Ssu-Yin [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Chang, Chia-Chiang; Wu, Chin-Jyi [Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan (China)

2014-04-01

Highlights: • The electrodes of bi-layer GZO/ ZnO and single-layer GZO in α-IGZO TFT were compared. • The TFT performances of two different structures were systematically investigated. • The bi-layer GZO/100-nm ZnO S/D electrodes showed the better TFT device properties. - Abstract: In this research, top-gate bottom-contact thin-film transistors (TFTs) made with amorphous indium gallium zinc oxide (α-IGZO) active layers were grown using the radio-frequency sputtering technique. Two kinds of source and drain (S/D) electrodes, namely bi-layer GZO/100-nm ZnO buffer layer/Corning 1737 and single-layer GZO/Corning 1737, used in the TFT devices and the electric characteristics of the devices were compared. To explain the differences in the TFT performances with these different S/D electrodes, X-ray reflectivity (XRR) and contact angles were measured. The α-IGZO TFT with the bi-layer GZO/100-nm ZnO buffer layer structure as S/D electrodes exhibited superior device performance compared to that of the TFT with a single-layer GZO structure, with a higher thin film density (5.94 g/cm{sup 3}), lower surface roughness (0.817 nm), and larger surface energy (62.07 mJ/m{sup 2}) and better adhesion properties of neighboring α-IGZO films. In addition, the mechanisms responsible for the GZO/100-nm ZnO buffer layer/Corning 1737 structure S/D electrodes improving the device characteristics were systematically investigated. The α-IGZO TFT saturation mobility, subthreshold voltage, on/off current ratio, and the trap density of the GZO/100-nm ZnO buffer layer/Corning 1737 S/D electrodes were 13.5 cm{sup 2} V{sup −1} S{sup −1}, 0.43 V/decade, 3.56 × 10{sup 7}, and 5.65 × 10{sup 12} eV{sup −1} cm{sup −2}, respectively, indicating the potential of this bi-layer structure to be applied to large-area flat-panel displays.

Comparison of physical and electrical properties of GZO/ZnO buffer layer and GZO as source and drain electrodes of α-IGZO thin-film transistors

International Nuclear Information System (INIS)

Wu, Jia-Ling; Lin, Han-Yu; Su, Bo-Yuan; Chen, Yu-Cheng; Chu, Sheng-Yuan; Liu, Ssu-Yin; Chang, Chia-Chiang; Wu, Chin-Jyi

2014-01-01

Highlights: • The electrodes of bi-layer GZO/ ZnO and single-layer GZO in α-IGZO TFT were compared. • The TFT performances of two different structures were systematically investigated. • The bi-layer GZO/100-nm ZnO S/D electrodes showed the better TFT device properties. - Abstract: In this research, top-gate bottom-contact thin-film transistors (TFTs) made with amorphous indium gallium zinc oxide (α-IGZO) active layers were grown using the radio-frequency sputtering technique. Two kinds of source and drain (S/D) electrodes, namely bi-layer GZO/100-nm ZnO buffer layer/Corning 1737 and single-layer GZO/Corning 1737, used in the TFT devices and the electric characteristics of the devices were compared. To explain the differences in the TFT performances with these different S/D electrodes, X-ray reflectivity (XRR) and contact angles were measured. The α-IGZO TFT with the bi-layer GZO/100-nm ZnO buffer layer structure as S/D electrodes exhibited superior device performance compared to that of the TFT with a single-layer GZO structure, with a higher thin film density (5.94 g/cm 3 ), lower surface roughness (0.817 nm), and larger surface energy (62.07 mJ/m 2 ) and better adhesion properties of neighboring α-IGZO films. In addition, the mechanisms responsible for the GZO/100-nm ZnO buffer layer/Corning 1737 structure S/D electrodes improving the device characteristics were systematically investigated. The α-IGZO TFT saturation mobility, subthreshold voltage, on/off current ratio, and the trap density of the GZO/100-nm ZnO buffer layer/Corning 1737 S/D electrodes were 13.5 cm 2 V −1 S −1 , 0.43 V/decade, 3.56 × 10 7 , and 5.65 × 10 12 eV −1 cm −2 , respectively, indicating the potential of this bi-layer structure to be applied to large-area flat-panel displays

Low-Temperature Preparation of (111)-oriented Pb(Zr,Ti)O3 Films Using Lattice-Matched (111)SrRuO3/Pt Bottom Electrode by Metal-Organic Chemical Vapor Deposition

Science.gov (United States)

Kuwabara, Hiroki; Sumi, Akihiro; Okamoto, Shoji; Hoko, Hiromasa; Cross, Jeffrey S.; Funakubo, Hiroshi

2009-04-01

Pb(Zr0.35Ti0.65)O3 (PZT) films 170 nm thick were prepared at 415 °C by pulsed metal-organic chemical vapor deposition. The (111)-oriented PZT films with local epitaxial growth were obtained on (111)SrRuO3/(111)Pt/TiO2/SiO2/Si substrates and their ferroelectricities were ascertained. Ferroelectricity was improved by postannealing under O2 gas flow up to 550 °C. Larger remanent polarization and better fatigue endurance were obtained using a SrRuO3 top electrode compared to a Pt top electrode for PZT films after annealing at 500 °C.

Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

Science.gov (United States)

West, R. M.; Semancik, S.

2016-11-01

Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

Strategies of Miniaturised Reference Electrodes Integrated in a Silicon Based “one chip” pH Sensor

OpenAIRE

Simonis, Anette; Lüth, Hans; Wang, Joseph; Schöning, J.

2003-01-01

Different types of Ag/AgCl reference electrodes have been realised by means of thin- and thick-film technique. For inner electrolyte, KCl-containing membranes have been deposited and different coatings have been used to protect the reference electrode from a fast leaching out of KCl. The stability of the potential of the reference electrodes without KClcontaining membranes in 3 M KCl was about 7 hours for thin-film electrodes and up to 90 hours for thick-film electrodes. The reference electro...

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.

A „Hybrid“ Thin-Film pH Sensor with Integrated Thick-Film Reference

OpenAIRE

Simonis, Anette; Krings, Thomas; Lüth, Hans; Wang, Joseph; Schöning, Michael J.

2001-01-01

A reference electrode fabricated by means of thick-film technique is deposited onto a silicon substrate and combined with a thin-film pH sensor to a “hybrid†chip system. To evaluate the suitability of this combination, first investigations were carried out. The characteristics of the thin-film pH sensor were studied towards the thick-film Ag/AgCl reference electrode. Measurements were performed in the capacitance/voltage (C/V) and constant capacitance (Concap) mode for different pH ...

On the Preparation and Testing of Fuel Cell Catalysts Using the Thin Film Rotating Disk Electrode Method.

Science.gov (United States)

Inaba, Masanori; Quinson, Jonathan; Bucher, Jan Rudolf; Arenz, Matthias

2018-03-16

We present a step-by-step tutorial to prepare proton exchange membrane fuel cell (PEMFC) catalysts, consisting of Pt nanoparticles (NPs) supported on a high surface area carbon, and to test their performance in thin film rotating disk electrode (TF-RDE) measurements. The TF-RDE methodology is widely used for catalyst screening; nevertheless, the measured performance sometimes considerably differs among research groups. These uncertainties impede the advancement of new catalyst materials and, consequently, several authors discussed possible best practice methods and the importance of benchmarking. The visual tutorial highlights possible pitfalls in the TF-RDE testing of Pt/C catalysts. A synthesis and testing protocol to assess standard Pt/C catalysts is introduced that can be used together with polycrystalline Pt disks as benchmark catalysts. In particular, this study highlights how the properties of the catalyst film on the glassy carbon (GC) electrode influence the measured performance in TF-RDE testing. To obtain thin, homogeneous catalyst films, not only the catalyst preparation, but also the ink deposition and drying procedures are essential. It is demonstrated that an adjustment of the ink's pH might be necessary, and how simple control measurements can be used to check film quality. Once reproducible TF-RDE measurements are obtained, determining the Pt loading on the catalyst support (expressed as Pt wt%) and the electrochemical surface area is necessary to normalize the determined reaction rates to either surface area or Pt mass. For the surface area determination, so-called CO stripping, or the determination of the hydrogen underpotential deposition (Hupd) charge, are standard. For the determination of the Pt loading, a straightforward and cheap procedure using digestion in aqua regia with subsequent conversion of Pt(IV) to Pt(II) and UV-vis measurements is introduced.

Trace vanadium analysis by catalytic adsorptive stripping voltammetry using mercury-coated micro-wire and polystyrene-coated bismuth film electrodes

Energy Technology Data Exchange (ETDEWEB)

Dansby-Sparks, Royce; Chambers, James Q. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600 (United States); Xue Ziling, E-mail: xue@ion.chem.utk.edu [Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600 (United States)

2009-06-08

An electrochemical technique has been developed for ultra-trace (ng L{sup -1}) vanadium (V) measurement. Catalytic adsorptive stripping voltammetry for V analysis was developed at mercury-coated gold micro-wire electrodes (MWEs, 100 {mu}m) in the presence of gallic acid (GA) and bromate ion. A potential of -0.275 V (vs Ag/AgCl) was used to accumulate the complex in acetate buffer (pH 5.0) at the electrode surface followed by a differential pulse voltammetric scan. Parameters affecting the electrochemical response, including pH, concentration of GA and bromate, deposition potential and time have been optimized. Linear response was obtained in the 0-1000 ng L{sup -1} range (2 min deposition), with a detection limit of 0.88 ng L{sup -1}. The method was validated by comparison of results for an unknown solution of V by atomic absorption measurement. The protocol was evaluated in a real sample by measuring the amount of V in river water samples. Thick bismuth film electrodes with protective polystyrene films have also been made and evaluated as a mercury free alternative. However, ng L{sup -1} level detection was only attainable with extended (10 min) deposition times. The proposed use of MWEs for the detection of V is sensitive enough for future use to test V concentration in biological fluids treated by the advanced oxidation process (AOP).

Design and Fabrication of Low Cost Thick Film pH Sensor using Silver Chlorinated Reference Electrodes with Integrated Temperature Sensor

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Wiranto Goib

2016-01-01

Full Text Available This paper describes the design and fabrication of thick film pH sensor, in which the reference electrode has been formed by chlorination of Ag using FeCl3. The process was aimed to replace Ag/AgCl paste commonly used as reference electrodes. Fabricated using thick film screen printing technology on Al2O3 substrate, the pH sensor showed a measured sensitivity of -52.97, -53.17 and -53.68 mV/pH at 25°C, 45°C, and 65°C, respectively. The measured values were close to the theoretical Nernstian slope of -59 mV/pH 25°C.The sensor was also designed with an integrated Ruthenium based temperature sensor for future temperature compensation. The measured resistance temperature characteristics showed a linear reasponse over the range of 25 – 80°C. This miniaturised planar sensor should find wide application, especially in field water quality monitoring, replacing their glass type counterparts.

pH sensing in aqueous solutions using a MnO{sub 2} thin film electrodeposited on a glassy carbon electrode

Energy Technology Data Exchange (ETDEWEB)

Cherchour, N. [Laboratoire de Technologie des Materiaux et Genie des Procedes (LTMGP), Departement de Genie des Procedes, Universite A. Mira, Route de Targa Ouzemmour, 06000 Bejaia (Algeria); CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); Deslouis, C. [CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); Messaoudi, B. [Laboratoire de Technologie des Materiaux et Genie des Procedes (LTMGP), Departement de Genie des Procedes, Universite A. Mira, Route de Targa Ouzemmour, 06000 Bejaia (Algeria); Pailleret, A., E-mail: alain.pailleret@upmc.fr [CNRS, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France); UPMC Univ. Paris VI, UPR 15, Laboratoire Interfaces et Systemes Electrochimiques (LISE, case courrier 133), 4 Place Jussieu, F-75005 Paris (France)

2011-11-30

An electrolysis technique at a constant potential was used to develop a highly reproducible and fast elaboration method of adherent manganese dioxide thin films on a glassy carbon electrode from aqueous solutions containing sulfuric acid and manganese sulfate. The resulting films were found to have a nanostructured character presumably due rather to birnessite ({delta}-MnO{sub 2}) than to {gamma}-MnO{sub 2}, as suggested by their Raman and XRD signatures. They lead to modified electrodes that present an obvious although complex pH dependent potentiometric response. This sensor indeed showed a single slope non-Nernstian linear behaviour over the 1.5-12 pH range for increasing pH direction ('trace'), whereas a Nernstian two slopes linear behaviour was observed for decreasing pH direction ('re-trace'). Preliminary EIS experiments carried out at a pH value of 1.8 seem to reveal a sensitivity mechanism based on proton insertion process at least at highly acidic pH values.

Direct Inkjet Printing of Silver Source/Drain Electrodes on an Amorphous InGaZnO Layer for Thin-Film Transistors.

Science.gov (United States)

Ning, Honglong; Chen, Jianqiu; Fang, Zhiqiang; Tao, Ruiqiang; Cai, Wei; Yao, Rihui; Hu, Shiben; Zhu, Zhennan; Zhou, Yicong; Yang, Caigui; Peng, Junbiao

2017-01-10

Printing technologies for thin-film transistors (TFTs) have recently attracted much interest owing to their eco-friendliness, direct patterning, low cost, and roll-to-roll manufacturing processes. Lower production costs could result if electrodes fabricated by vacuum processes could be replaced by inkjet printing. However, poor interfacial contacts and/or serious diffusion between the active layer and the silver electrodes are still problematic for achieving amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs with good electrical performance. In this paper, silver (Ag) source/drain electrodes were directly inkjet-printed on an amorphous a-IGZO layer to fabricate TFTs that exhibited a mobility of 0.29 cm²·V -1 ·s -1 and an on/off current ratio of over 10⁵. To the best of our knowledge, this is a major improvement for bottom-gate top-contact a-IGZO TFTs with directly printed silver electrodes on a substrate with no pretreatment. This study presents a promising alternative method of fabricating electrodes of a-IGZO TFTs with desirable device performance.

Direct Inkjet Printing of Silver Source/Drain Electrodes on an Amorphous InGaZnO Layer for Thin-Film Transistors

Directory of Open Access Journals (Sweden)

Honglong Ning

2017-01-01

Full Text Available Printing technologies for thin-film transistors (TFTs have recently attracted much interest owing to their eco-friendliness, direct patterning, low cost, and roll-to-roll manufacturing processes. Lower production costs could result if electrodes fabricated by vacuum processes could be replaced by inkjet printing. However, poor interfacial contacts and/or serious diffusion between the active layer and the silver electrodes are still problematic for achieving amorphous indium–gallium–zinc–oxide (a-IGZO TFTs with good electrical performance. In this paper, silver (Ag source/drain electrodes were directly inkjet-printed on an amorphous a-IGZO layer to fabricate TFTs that exhibited a mobility of 0.29 cm2·V−1·s−1 and an on/off current ratio of over 105. To the best of our knowledge, this is a major improvement for bottom-gate top-contact a-IGZO TFTs with directly printed silver electrodes on a substrate with no pretreatment. This study presents a promising alternative method of fabricating electrodes of a-IGZO TFTs with desirable device performance.

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)

Gao, R.; Zheng, J.; Zheng, X.

2011-01-01

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 CeO 2 nanoparticles (nano-CeO 2 ) 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-CeO 2 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 (ΔE p ) and the formal potential (E σ ) 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)

Facile Synthesis of Nanosheet-like CuO Film and its Potential Application as a High-Performance Pseudocapacitor Electrode

International Nuclear Information System (INIS)

Nwanya, Assumpta C.; Obi, Daniel; Ozoemena, Kenneth I.; Osuji, Rose U.; Awada, Chawki; Ruediger, Andreas; Maaza, Malik

2016-01-01

We describe the chemical synthesis of binderless and surfactant free CuO films for pseudocapacitive applications. Nanosheet-like and nanorod-like CuO films are deposited on indium tin oxide (ITO) substrates using the successive ionic layer adsorption and reaction (SILAR) approach. The nanostructured CuO shows uniform surface morphology and uniform pore distribution with average grain sizes in the range 30 − 50 nm and average pore size of 12.0 and 12.5 nm for 10 and for 40-cycles respectively, as estimated from AFM imaging. The electrochemical properties are characterized by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The highest specific capacitance of 566.33 Fg"−"1 is obtained for as low as 10-cycle film at a scan rate of 5mVs"−"1. The long term stability tests by continuous GCD, indicates that there is no degradation after 1000 cycles with the film yielding 100% coulombic efficiency. This indicates a high stability of the synthesized CuO films. Hence, the developed nanostructured CuO film electrodes exhibit excellent properties for use as supercapacitors.

Fabrication of Dye-Sensitized Solar Cells with a 3D Nanostructured Electrode

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Guo-Yang Chen

2010-01-01

Full Text Available A novel Dye-Sensitized Solar Cell (DSSC scheme for better solar conversion efficiency is proposed. The distinctive characteristic of this novel scheme is that the conventional thin film electrode is replaced by a 3D nanostructured indium tin oxide (ITO electrode, which was fabricated using RF magnetron sputtering with an anodic aluminum oxide (AAO template. The template was prepared by immersing the barrier-layer side of an AAO film into a 30 wt% phosphoric acid solution to produce a contrasting surface. RF magnetron sputtering was then used to deposit a 3D nanostructured ITO thin film on the template. The crystallinity and conductivity of the 3D ITO films were further enhanced by annealing. Titanium dioxide nanoparticles were electrophoretically deposited on the 3D ITO film after which the proposed DSSC was formed by filling vacant spaces in the 3D nanostructured ITO electrode with dye. The measured solar conversion efficiency of the device was 0.125%. It presents a 5-fold improvement over that of conventional spin-coated TiO2 film electrode DSSCs.

Effect of Calendering on Electrode Wettability in Lithium Ion Batteries

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Yangping eSheng

2014-12-01

Full Text Available Controlling the wettability between the porous electrode and the electrolyte in lithium ion batteries can improve both the manufacturing process and the electrochemical performance of the cell. The wetting rate, which is the electrolyte transport rate in the porous electrode, can be quantified using the wetting balance. The effect of the calendering process on the wettability of anode electrodes was investigated. A graphite anode film with an as-coated thickness of 59 μm was used as baseline electrode film and was calendered to produce films with thickness ranging from 55 to 41 µm. Results show that wettability is improved by light calendering from an initial thickness of 59 μm to a calendered thickness of 53 μm where the wetting rate increased from 0.375 to 0.589 mm/s0.5. Further calendering below 53 µm resulted in a decrease in wetting rates to a minimum observed value of 0.206 mm/s0.5 at a calendered thickness of 41 μm. Under the same electrolyte, wettability of the electrode is controlled to a great extent by the pore structure in the electrode film which includes parameters such as porosity, pore size distribution, pore geometry and topology. Relations between the wetting behavior and the pore structure as characterized by mercury intrusion and electron microscopy exist and can be used to manipulate the wetting behavior of electrodes.

Vacuum-Assisted Low-Temperature Synthesis of Reduced Graphene Oxide Thin-Film Electrodes for High-Performance Transparent and Flexible All-Solid-State Supercapacitors.

Science.gov (United States)

Aytug, Tolga; Rager, Matthew S; Higgins, Wesley; Brown, Forrest G; Veith, Gabriel M; Rouleau, Christopher M; Wang, Hui; Hood, Zachary D; Mahurin, Shannon M; Mayes, Richard T; Joshi, Pooran C; Kuruganti, Teja

2018-04-04

Simple and easily integrated design of flexible and transparent electrode materials affixed to polymer-based substrates hold great promise to have a revolutionary impact on the functionality and performance of energy storage devices for many future consumer electronics. Among these applications are touch sensors, roll-up displays, photovoltaic cells, health monitors, wireless sensors, and wearable communication devices. Here, we report an environmentally friendly, simple, and versatile approach to produce optically transparent and mechanically flexible all-solid-state supercapacitor devices. These supercapacitors were constructed on tin-doped indium oxide coated polyethylene terephthalate substrates by intercalation of a polymer-based gel electrolyte between two reduced graphene oxide (rGO) thin-film electrodes. The rGO electrodes were fabricated simply by drop-casting of graphene oxide (GO) films, followed by a novel low-temperature (≤250 °C) vacuum-assisted annealing approach for the in situ reduction of GO to rGO. A trade-off between the optical transparency and electrochemical performance is determined by the concentration of the GO in the initial dispersion, whereby the highest capacitance (∼650 μF cm -2 ) occurs at a relatively lower optical transmittance (24%). Notably, the all-solid-state supercapacitors demonstrated excellent mechanical flexibility with a capacity retention rate above 90% under various bending angles and cycles. These attributes underscore the potential of the present approach to provide a path toward the realization of thin-film-based supercapacitors as flexible and transparent energy storage devices for a variety of practical applications.

Spray pyrolysed Ru:TiO2 thin film electrodes prepared for electrochemical supercapacitor

Science.gov (United States)

Fugare, B. Y.; Thakur, A. V.; Kore, R. M.; Lokhande, B. J.

2018-04-01

Ru doped TiO2 thin films are prepared by using 0.06 M aqueous solution of potassium titanium oxalate (pto), and 0.005 M aqueous solution of ruthenium tri chloride (RuCl3) precursors. The deposition was carried on stainless steel (SS) by using well known ultrasonic spray pyrolysis technique (USPT) at 723° K by maintaining the spray rate 12 cc/min and compressed air flow rate 10 Lmin-1. Prepared Ru:TiO2 thin films were characterized by structurally, morphologically and electrochemically. Deposited RuO2 shows amorphous structure and TiO2 shows tetragonal crystal structure with rutile as prominent phase at very low decomposition temperature. SEM micrographs of RuO2 exhibits porous, interconnected, spherical grains type morphology and TiO2 shows porous, nanorods and nanoplates like morphology and also Ru doped TiO2 shows porous, spherical, granular and nanorods type morphology. The electrochemical cyclic voltammetery shows mixed capacitive behavior. The achieved highest value of specific capacitance 2692 F/g was Ru doped TiO2 electrode in 0.5 M H2SO4.

Electrochemical properties of polypyrrole/polyfuran polymer composite electrode

International Nuclear Information System (INIS)

Cha, Seong Keuck

1998-01-01

Poly pyrrole polymer(ppy) has an excellent electrical conductivity and can be easily polymerized on anode to give various morphology according to doped anion on electroactive sites. To improve the properties of brittleness, ageing and hydrophobicity, poly furan polymer(pfu) having a high initiation potential was anodically implanted in this porous ppy film matrix to get the Pt/ppy/pfu(x)type of polymer campsite electrode. Cyclic voltammetry and electrochemical impedance methods were used to these electrode, where PF 6 - , BF 4 - , and ClO 4 - ions were employed as dopants. The composition of the pfu(x) at the electrode was changed from 0 to 1.10, but the range was useful only at 0.1 to 0.2 as the redox electrode. The polymer composite electrode doped with PF 6 - was better in charge transfer resistance by a factor of 40 times and in double layer capacitance by a factor of 20 times than others. The charge transfer in the polymer film of the electrode was influenced on frequency change and equivalent circuit of this electrode had Warburg impedance including mass transfer

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Transparent and flexible supercapacitors with single walled carbon nanotube thin film electrodes.

Science.gov (United States)

Yuksel, Recep; Sarioba, Zeynep; Cirpan, Ali; Hiralal, Pritesh; Unalan, Husnu Emrah

2014-09-10

We describe a simple process for the fabrication of transparent and flexible, solid-state supercapacitors. Symmetric electrodes made up of binder-free single walled carbon nanotube (SWCNT) thin films were deposited onto polydimethylsiloxane substrates by vacuum filtration followed by a stamping method, and solid-state supercapacitor devices were assembled using a gel electrolyte. An optical transmittance of 82% was found for 0.02 mg of SWCNTs, and a specific capacitance of 22.2 F/g was obtained. The power density can reach to 41.5 kW · kg(-1) and shows good capacity retention (94%) upon cycling over 500 times. Fabricated supercapacitors will be relevant for the realization of transparent and flexible devices with energy storage capabilities, displays and touch screens in particular.

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.

Digital simulation of anodic stripping voltammetry from thin film electrodes

International Nuclear Information System (INIS)

Magallanes, J.F.

1984-01-01

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.) [es

A full-wafer fabrication process for glass microfluidic chips with integrated electroplated electrodes by direct bonding of dry film resist

International Nuclear Information System (INIS)

Vulto, Paul; Urban, G A; Huesgen, Till; Albrecht, Björn

2009-01-01

A full-wafer process is presented for fast and simple fabrication of glass microfluidic chips with integrated electroplated electrodes. The process employs the permanent dry film resist (DFR) Ordyl SY300 to create microfluidic channels, followed by electroplating of silver and subsequent chlorination. The dry film resist is bonded directly to a second substrate, without intermediate gluing layers, only by applying pressure and moderate heating. The process of microfluidic channel fabrication, electroplating and wafer bonding can be completed within 1 day, thus making it one of the fastest and simplest full-wafer fabrication processes. (note)

A hydroxylamine electrochemical sensor based on electrodeposition of porous ZnO nanofilms onto carbon nanotubes films modified electrode

Energy Technology Data Exchange (ETDEWEB)

Zhang Cuihong; Wang Guangfeng; Liu Min; Feng Yuehua; Zhang Zhidan [College of Chemistry and Materials Science, Anhui Key Laboratory of Chem-Biosensing, Beijing East Road No. 1, Anhui Normal University, Anhui, Wuhu 241000 (China); Fang Bin, E-mail: binfang_47@yahoo.com.c [College of Chemistry and Materials Science, Anhui Key Laboratory of Chem-Biosensing, Beijing East Road No. 1, Anhui Normal University, Anhui, Wuhu 241000 (China)

2010-03-01

A novel route (electrodeposition) for the fabrication of porous ZnO nanofilms attached multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrodes (GCEs) was proposed. The morphological characterization of ZnO/MWCNT films was examined by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The performances of the ZnO/MWCNTs/GCE were characterized with cyclic voltammetry (CV), Nyquist plot (EIS) and typical amperometric response (i-t). The potential utility of electrodes constructed was demonstrated by applying them to the analytical determination of hydroxylamine concentration. An optimized limit of detection of 0.12 muM was obtained at a signal-to-noise ratio of 3 and with a fast response time (within 3 s). Additionally, the ZnO/MWCNTs/GCE exhibited a wide linear range from 0.4 to 1.9 x 10{sup 4} muM and higher sensitivity. The ease of fabrication, high stability, and low cost of the modified electrode are the promising features of the proposed sensor.

Enhanced performance of amorphous In-Ga-Zn-O thin-film transistors using different metals for source/drain electrodes

Science.gov (United States)

Pyo, Ju-Young; Cho, Won-Ju

2017-09-01

In this paper, we propose an amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) with off-planed source/drain electrodes. We applied different metals for the source/drain electrodes with Ni and Ti to control the work function as high and low. When we measured the configuration of Ni to drain and source to Ti, the a-IGZO TFT showed increased driving current, decreased leakage current, a high on/off current ratio, low subthreshold swing, and high mobility. In addition, we conducted a reliability test with a gate bias stress test at various temperatures. The results of the reliability test showed the Ni drain and Ti drain had an equivalent effective energy barrier height. Thus, we confirmed that the proposed off-planed structure improved the electrical characteristics of the fabricated devices without any degradation of characteristics. Through the a-IGZO TFT with different source/drain electrode metal engineering, we realized high-performance TFTs for next-generation display devices.

Fabrication of TiNb{sub 2}O{sub 7} thin film electrodes for Li-ion micro-batteries by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Daramalla, V. [Materials Research Centre, Indian Institute of Science, Bengalore 560012 (India); Penki, Tirupathi Rao; Munichandraiah, N. [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengalore 560012 (India); Krupanidhi, S.B., E-mail: sbk@mrc.iisc.ernet.in [Materials Research Centre, Indian Institute of Science, Bengalore 560012 (India)

2016-11-15

Graphical abstract: The TiNb{sub 2}O{sub 7} thin film electrodes as anode material in Li-ion rechargeable micro-batteries are successfully demonstrated. The pulsed laser deposited TiNb{sub 2}O{sub 7} thin film electrode delivers high discharge specific capacity of 143 μAh μm{sup −1} cm{sup −2} at 50 μA cm{sup −2} current density, with 92% coulombic efficiency. The thin films are very stable in crystal structure, with good fast reversible reaction at average Li-insertion voltage 1.65 V. - Highlights: • TiNb{sub 2}O{sub 7} thin films fabricated by pulsed laser deposition. • TiNb{sub 2}O{sub 7} as anode thin films demonstrated successfully. • High discharge specific capacity with 92% coulombic efficiency. • Excellent crystal stability and good reversible reaction. - Abstract: Pulsed laser deposited TiNb{sub 2}O{sub 7} thin films are demonstrated as anode materials in rechargeable Li-ion micro-batteries. The monoclinic and chemically pure TiNb{sub 2}O{sub 7} films in different morphologies were successfully deposited at 750 °C. The single phase formation was confirmed by grazing incident X-ray diffraction, micro-Raman spectroscopy, high resolution transmission electron microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The oxygen partial pressure during the deposition significantly influenced the properties of TiNb{sub 2}O{sub 7} films. The TiNb{sub 2}O{sub 7} thin films exhibited excellent stability with fast kinetics reversible reaction. The TiNb{sub 2}O{sub 7} films showed initial discharge specific capacity of 176, 143 μAh μm{sup −1} cm{sup −2} at 30, 50 μA cm{sup −2} current densities respectively with 92% coulombic efficiency in a non-aqueous electrolyte consisting of Li{sup +} ions. The high discharge specific capacity of TiNb{sub 2}O{sub 7} thin films may be attributed to nanometer grain size with high roughness which offers high surface area for Li-diffusion during charge and discharge

Top-Contact Pentacene-Based Organic Thin Film Transistor (OTFT) with N, N'-Bis(3-Methyl Phenyl)- N, N'-Diphenyl Benzidine (TPD)/Au Bilayer Source-Drain Electrode

Science.gov (United States)

Borthakur, Tribeni; Sarma, Ranjit

2018-01-01

A top-contact Pentacene-based organic thin film transistor (OTFT) with N, N'-Bis (3-methyl phenyl)- N, N'-diphenyl benzidine (TPD)/Au bilayer source-drain electrode is reported. The devices with TPD/Au bilayer source-drain (S-D) electrodes show better performance than the single layer S-D electrode OTFT devices. The field-effect mobility of 4.13 cm2 v-1 s-1, the on-off ratio of 1.86 × 107, the threshold voltage of -4 v and the subthreshold slope of .27 v/decade, respectively, are obtained from the device with a TPD/Au bilayer source-drain electrode.

Pseudocapacitive performance of electrodeposited porous Co3O4 film on electrophoretically modified graphite electrodes with carbon nanotubes

Science.gov (United States)

Kazazi, Mahdi; Sedighi, Ali Reza; Mokhtari, Mohammad Amin

2018-05-01

A facile and efficient two-step procedure was developed for the fabrication of a high-performance and binder-free cobalt oxide-carbon nanotubes (CO/CNT) pseudocapacitive electrode. First, CNTs were deposited on the surface of a chemically activated graphite sheet by cathodic electrophoretic deposition technique from their ethanolic suspension. In the next step, a thin film of cobalt oxide was electrodeposited on the CNTs coated graphite substrate by a galvanostatic method, followed by a thermal treatment in air. The structure and morphology of the prepared cobaltite electrode with and without CNT interlayer were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and nitrogen adsorption-desorption measurement. The results indicated that Co3O4 nanoparticles were uniformly attached on the surface of CNTs, to form a porous-structured CO/CNT composite electrode with a high specific surface area of 144.9 m2 g-1. Owing to the superior electrical conductivity of CNTs, high surface area and open porous structure, and improved integrity of the electrode structure, the composite electrode delivered a high areal capacitance of 4.96F cm-2 at a current density of 2 mA cm-2, a superior rate performance (64.7% capacitance retention from 2 mA cm-2 to 50 mA cm-2), as well as excellent cycling stability (91.8% capacitance retention after 2000 cycles), which are higher than those of the pure cobaltite electrode.

Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

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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.

Acoustic performance of dual-electrode electrostatic sound generators based on CVD graphene on polyimide film.

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Lee, Kyoung-Ryul; Jang, Sung Hwan; Jung, Inhwa

2018-08-10

We investigated the acoustic performance of electrostatic sound-generating devices consisting of bi-layer graphene on polyimide film. The total sound pressure level (SPL) of the sound generated from the devices was measured as a function of source frequency by sweeping, and frequency spectra were measured at 1/3 octave band frequencies. The relationship between various operation conditions and total SPL was determined. In addition, the effects of changing voltage level, adding a DC offset, and using two pairs of electrodes were evaluated. It should be noted that two pairs of electrode operations improved sound generation by about 10 dB over all frequency ranges compared with conventional operation. As for the sound-generating capability, total SPL was 70 dBA at 4 kHz when an AC voltage of 100 V pp was applied with a DC offset of 100 V. Acoustic characteristics differed from other types of graphene-based sound generators, such as graphene thermoacoustic devices and graphene polyvinylidene fluoride devices. The effects of diameter and distance between electrodes were also studied, and we found that diameter greatly influenced the frequency response. We anticipate that the design information provided in this paper, in addition to describing key parameters of electrostatic sound-generating devices, will facilitate the commercial development of electrostatic sound-generating systems.

Effect of electrode type in the resistive switching behaviour of TiO2 thin films

International Nuclear Information System (INIS)

Hernández-Rodríguez, E; Zapata-Torres, M; Márquez-Herrera, A; Zaleta-Alejandre, E; Meléndez-Lira, M; Cruz, W de la

2013-01-01

The influence of the electrode/active layer on the electric-field-induced resistance-switching phenomena of TiO 2 -based metal-oxide-metal devices (MOM) is studied. TiO 2 active layers were fabricated by the reactive rf-sputtering technique and devices were made by sandwiching between several metal electrodes. Three different MOM devices were made, according with the junction type formed between the electrode and the TiO 2 active layer, those where Ohmic-Ohmic, Ohmic-Schottky and Schottky-Schottky. The junction type was tested by electrical I-V measurements. It was found that MOM devices made with the Ohmic-Ohmic combination did not show any resistive switching behaviour in contrast with devices made with Ohmic-Schottky and Schottky-Schottky combinations. From a detailed analysis of the I-V curves it was found that transport characteristics are Ohmic for the low-resistance state for all the contacts combinations of the MOM devices, whereas in the high-resistance state it depends on contact combinations and can be identified as Ohmic, Schottky and Poole-Frenkel type. These conduction mechanisms in the low- and high-resistance states suggest that formation and rupture of conducting filaments through the film oxide is the mechanism responsible for the resistance switching.

Effects of Thickness, Pulse Duration, and Size of Strip Electrode on Ferroelectric Electron Emission of Lead Zirconate Titanate Films

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Yaseen, Muhammad; Ren, Wei; Chen, Xiaofeng; Feng, Yujun; Shi, Peng; Wu, Xiaoqing

2018-02-01

Sol-gel-derived lead zirconate titanate (PZT) thin-film emitters with thickness up to 9.8 μm have been prepared on Pt/TiO2/SiO2/Si wafer via chemical solution deposition with/without polyvinylpyrrolidone (PVP) modification, and the relationship between the film thickness and electron emission investigated. Notable electron emission was observed on application of a trigger voltage of 120 V for PZT film with thickness of 1.1 μm. Increasing the film thickness decreased the threshold field to initiate electron emission for non-PVP-modified films. In contrast, the electron emission behavior of PVP-modified films did not show significant dependence on film thickness, probably due to their porous structure. The emission current increased with decreasing strip width and space between strips. Furthermore, it was observed that increasing the duration of the applied pulse increased the magnitude of the emission current. The stray field on the PZT film thickness was also calculated and found to increase with increasing ferroelectric sample thickness. The PZT emitters were found to be fatigue free up to 105 emission cycles. Saturated emission current of around 25 mA to 30 mA was achieved for the electrode pattern used in this work.

Peroxynitrite Sensor Based on a Screen Printed Carbon Electrode Modified with a Poly(2,6-dihydroxynaphthalene Film

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Ioana Silvia Hosu

2016-11-01

Full Text Available For the first time the electropolymerization of 2,6-dihydroxynaphthalene (2,6-DHN on a screen printed carbon electrode (SPCE was investigated and evaluated for peroxynitrite (PON detection. Cyclic voltammetry was used to electrodeposit the poly(2,6-DHN on the carbon electrode surface. The surface morphology and structure of poly(2,6-DHN film were investigated by SEM and FTIR analysis, and the electrochemical features by cyclic voltammetry. The poly(2,6-DHN/SPCE sensor showed excellent electrocatalytic activity for PON oxidation in alkaline solutions at very low potentials (0–100 mV vs. Ag/AgCl pseudoreference. An amperometric FIA (flow injection analysis system based on the developed sensor was optimized for PON measurements and a linear concentration range from 2 to 300 μM PON, with a LOD of 0.2 μM, was achieved. The optimized sensor inserted in the FIA system exhibited good sensitivity (4.12 nA·μM−1, selectivity, stability and intra-/inter-electrode reproducibility for PON determination.

Flexible transparent electrode

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Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

2011-06-01

This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

Ammonium ions determination with polypyrrole modified electrode

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Luiz Henrique Dall´Antonia

2007-03-01

Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

Polypyrrole electrodes doped with sulfanilic acid azochromotrop for electrochemical supercapacitors

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Chen, S.; Zhitomirsky, I.

2013-12-01

In this work we demonstrate the feasibility of deposition of polypyrrole (PPy) films by electropolymerization on stainless steel substrates and fabrication of PPy powders by chemical polymerization using sulfanilic acid azochromotrop (SPADNS) as a new anionic dopant. The problem of low adhesion of PPy films to stainless steel substrates is addressed by the use of SPADNS, which exhibits chelating properties, promoting film formation. The use of fine particles, prepared by the chemical polymerization method, allows impregnation of Ni foams and fabrication of porous electrodes with high materials loading for electrochemical supercapacitors (ES). PPy films and Ni foam based PPy electrodes show capacitive behaviour in Na2SO4 electrolyte. The electron microscopy studies, impedance spectroscopy data and analysis of the SPADNS structure provide an insight into the factors, controlling capacitive behaviour. The Ni foam based electrodes offer advantages of improved capacitive behaviour at high materials loadings and good cycling stability. The area normalized and volume normalized specific capacitances are as high as 5.43 F cm-2 and 93.6 F cm-3, respectively, for materials loading of 35.4 mg cm-2. The capacitance retention of Ni foam based electrodes is 91.5% after 1000 cycles. The Ni foam based PPy electrodes are promising for application in ES.

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

International Nuclear Information System (INIS)

Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H.; Kinge, Sachin

2015-01-01

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 2 layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10 −2  A W −1 and a shot-derived specific detectivity of 3 × 10 9  Jones at 1530 nm wavelength

Uniform thin film electrode made of low-temperature-sinterable silver nanoparticles: optimized extent of ligand exchange from oleylamine to acrylic acid

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung Jong; Kim, Na Rae; Lee, Changsoo; Lee, Hyuck Mo, E-mail: hmlee@kaist.ac.kr [Department of Materials Science and Engineering (Korea, Republic of)

2017-02-15

Lowering the sintering temperature of nanoparticles in the electrode deposition process holds both academic and industrial interest because of the potential applications of such electrodes in polymer devices and flexible electronics. In addition, achieving uniform electrode formation after ligand exchange is equally important as lowering the sintering temperature. Here, we report a simple chemical treatment by the addition of ligand-exchanging interfaces to lower the sintering temperature; we also determine the optimum extent of ligand exchange for crack-free electrode formation. First, we investigated the structural change of Ag thin films with respect to the concentration of acrylic acid (AA) solutions. Second, we used thermal analysis to evaluate the effects of changes in the sintering temperature. We observed that the resulting conductivity of the Ag patterns was only one order of magnitude lower than that of bulk Ag when the patterns were sintered at 150 °C. The simple chemical treatment developed in this work for solution-processed Ag electrode formation can be adopted for flexible electronics, which would eliminate the need for vacuum and high-temperature processes.

Very sensitive electrochemical determination of diuron on glassy carbon electrode modified with reduced graphene oxide-gold nanoparticle-Nafion composite film.

Science.gov (United States)

Zarei, K; Khodadadi, A

2017-10-01

In this work, a very sensitive electrochemical sensor based on glassy carbon electrode (GCE) modified with reduced graphene oxide-gold nanoparticles/Nafion (rGO-AuNPs/Nafion) composite film was applied to determine diuron. Synthesized GO was characterized using X-ray diffraction (XRD) and UV-visible spectroscopy. The surface morphology of the rGO-AuNPs/Nafion film was also characterized using scanning electron microscopy and electrochemical impedance spectroscopy. Cyclic voltammetry (CV) and adsorptive differential pulse voltammetry (AdDPV) were applied to investigate the electrochemical response of the diuron on the modified electrode. The electrode showed a linear response at 1.0×10 -9 -1.0×10 -7 M and a detection limit of 0.3nM under the optimized conditions. The effect of some other species on the determination of diuron was investigated and the sensor showed good selectivity for determination of diuron. The constructed sensor was applied to determine diuron in enriched samples of orange juice, mineral and tap water which statistical t-test showed accuracy of method. Also the sensor was applied to obtain diuron content in the tea sample. The reliability of the proposed sensor was confirmed after comparing the results with those obtained using high performance liquid chromatography (HPLC) as a comparative method. Copyright © 2017 Elsevier Inc. All rights reserved.

Zn2+-Doped Polyaniline/Graphene Oxide as Electrode Material for Electrochemical Supercapacitors

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Xu, Hui; Tang, Jing; Chen, Yong; Liu, Jian; Pu, Jinjuan; Li, Qi

2017-10-01

Electrodes based on Zn2+-doped polyaniline/graphene oxide (Zn2+/PANI/GO) were synthesized on stainless steel mesh substrates in H2SO4 solution via electrochemical codeposition. Different concentrations of graphene oxide (GO) were incorporated into the films to improve the electrochemical performance of the electrodes. Electrochemical properties of the films were tested by cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectroscopy, in a three-electrode system. The maximum specific capacitance of the Zn2+/PANI/GO film with a GO concentration of 15 mg L-1 was found to be 1266 F g-1 at a scan rate of 3 mV s-1. This value was higher than that of a Zn2+ doped polyaniline (Zn2+/PANI) film (814 F g-1). The Zn2+/PANI/GO film also showed good cycling stability, retaining over 86% of its initial capacitance after 1000 cycles. These results indicate that the Zn2+/PANI/GO composites can be applied as high performance supercapacitor electrodes.

Cu mesh for flexible transparent conductive electrodes.

Science.gov (United States)

Kim, Won-Kyung; Lee, Seunghun; Hee Lee, Duck; Hee Park, In; Seong Bae, Jong; Woo Lee, Tae; Kim, Ji-Young; Hun Park, Ji; Chan Cho, Yong; Ryong Cho, Chae; Jeong, Se-Young

2015-06-03

Copper electrodes with a micromesh/nanomesh structure were fabricated on a polyimide substrate using UV lithography and wet etching to produce flexible transparent conducting electrodes (TCEs). Well-defined mesh electrodes were realized through the use of high-quality Cu thin films. The films were fabricated using radio-frequency (RF) sputtering with a single-crystal Cu target--a simple but innovative approach that overcame the low oxidation resistance of ordinary Cu. Hybrid Cu mesh electrodes were fabricated by adding a capping layer of either ZnO or Al-doped ZnO. The sheet resistance and the transmittance of the electrode with an Al-doped ZnO capping layer were 6.197 ohm/sq and 90.657%, respectively, and the figure of merit was 60.502 × 10(-3)/ohm, which remained relatively unchanged after thermal annealing at 200 °C and 1,000 cycles of bending. This fabrication technique enables the mass production of large-area flexible TCEs, and the stability and high performance of Cu mesh hybrid electrodes in harsh environments suggests they have strong potential for application in smart displays and solar cells.

Electrochemical behavior and voltammetric determination of acetaminophen based on glassy carbon electrodes modified with poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite films.

Science.gov (United States)

Zhu, Wencai; Huang, Hui; Gao, Xiaochun; Ma, Houyi

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Thin film bismuth iron oxides useful for piezoelectric devices

Science.gov (United States)

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.

In situ electrochemical atomic force microscope study on graphite electrodes

Energy Technology Data Exchange (ETDEWEB)

Hirasawa, K.A.; Sato, Tomohiro; Asahina, Hitoshi; Yamaguchi, Shoji; Mori, Shoichiro [Mitsubishi Chemical Corp., Inashiki, Ibaraki (Japan). Tsukuba Research Center

1997-04-01

Interest in the formation of the solid electrolyte interphase (SEI) film on graphite electrodes has increased recently in the quest to improve the performance of lithium-ion batteries. Topographic and frictional changes on the surface of a highly oriented pyrolytic graphite electrode in 1 M LiCiO{sub 4} ethylene carbonate/ethylmethyl carbonate (1:1) electrolyte were examined during charge and discharge by in situ electrochemical atomic force microscopy and friction force microscopy simultaneously in real-time. Solid electrolyte interphase film formation commenced at approximately 2 V vs. Li/Li{sup +} and stable film formation with an island-like morphology was observed below approximately 0.9 V vs. Li/Li{sup +}. Further experiments on a KS-44 graphite/polyvinylidene difluoride binder composite electrode showed similar phenomena.

Structure of electron collection electrode in dye-sensitized nanocrystalline TiO2

International Nuclear Information System (INIS)

Yanagida, Masatoshi; Numata, Youhei; Yoshimatsu, Keiichi; Ochiai, Masayuki; Naito, Hiroyoshi; Han, Liyuan

2013-01-01

As part of the effort to control electron transport in the TiO 2 films of dye-sensitized solar cells (DSCs), the structure of the electron collection electrode on the films has been investigated. Here, we report the comparison between a sandwich-type dye-sensitized solar cell (SW-DSC), in which the TiO 2 film is sandwiched between a TCO glass front electron collection electrode and a sputtered Ti back charge collection electrode, and a normal DSC (N-DSC), which has no back electrode. In N-DSCs, electrons in TiO 2 that are far from the front electrode have to diffuse for a long distance (ca. 10 μm), and therefore, the photocurrent cannot rapidly respond to light with a modulation frequency >100 Hz. In SW-DSCs, the photocurrent response was enhanced at frequencies between 10 and 500 Hz because electrons in TiO 2 can be extracted by both front and back electrodes, which can be also explained by an electron diffusion model. Calculations based on the electron diffusion model suggested that a high short-circuit photocurrent could be maintained in SW-DSCs even when the electron diffusion length in the TiO 2 film was shortened.

Determination of Lead(II), Cadmium(II) and Copper(II) in Waste-Water and Soil Extracts on Mercury Film Screen-Printed Carbon Electrodes Sensor

International Nuclear Information System (INIS)

Mohd Fairulnizal Md Noh; Tothill, I.E.

2011-01-01

A sensor incorporating a three electrodes configuration have been fabricated using low cost screen-printing technology. These electrodes couples with Square Wave Stripping Voltammetry (SWSV) has provided a convenient screening tool for on-site detection of trace levels of Pb(II), Cd(II) and Cu(II). Modification of the graphite carbon surface based on in situ deposition of mercury film has been carried out. By appropriate choice of supporting medium and optimized parameters setting such as amount of mercury used the deposition potential, deposition time, frequency and scan rate, well resolved and reproducible response for Pb(II), Cd(II) and Cu(II) were obtained. The performance characteristics of the developed mercury film screen printed carbon electrode (MFSPCE) for 120 s deposition time showed that the linear range for Cd(II), Pb(II) and Cu(II) were 10 to 200 μg L -1 . The detection limit recorded for Cd(II), Pb(II) and Cu(II) were 2, 1 and 5 μg L -1 with relative standard deviation (RSD) of 6.5 %, 6.9 % and 7.5 %, respectively. Successful applications of the sensing device to waste-water and extracted soil samples were demonstrated. (author)

Gate voltage and drain current stress instabilities in amorphous In–Ga–Zn–O thin-film transistors with an asymmetric graphene electrode

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Joonwoo Kim

2015-09-01

Full Text Available The gate voltage and drain current stress instabilities in amorphous In–Ga–Zn–O thin-film transistors (a-IGZO TFTs having an asymmetric graphene electrode structure are studied. A large positive shift in the threshold voltage, which is well fitted to a stretched-exponential equation, and an increase in the subthreshold slope are observed when drain current stress is applied. This is due to an increase in temperature caused by power dissipation in the graphene/a-IGZO contact region, in addition to the channel region, which is different from the behavior in a-IGZO TFTs with a conventional transparent electrode.

Nickel hydroxide modified electrodes for urea determination

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Luiz Henrique Dall´Antonia

2007-03-01

Full Text Available Nickel hydroxide films were prepared by electrodeposition from a solution Ni(NO32 0,05 mol L ?¹ on ITO electrodes (Tin oxide doped with Indium on PET-like plastic film, applying a current of - 0,1 A cm ?² during different time intervals between 1800 and 7200 s. The electrochemical behavior of the nickel hydroxide electrode was investigated through a cyclic voltammogram, in NaOH 1,0 mol L ?¹, where it was observed two peaks in the profile in 0,410 and 0,280 V, corresponding to redox couple Ni(II/Ni(III. A sensor for urea presenting a satisfactory answer can be obtained when, after the deposit of the film of Ni(OH2 on the electrode of nickel, it is immersed in a solution of NaOH 1,0 mol L ?¹ and applying a potential of + 0,435 V, where the maximum of the anodic current occurs in the cyclic voltammogram. Analyzing the results it can be observed that, for a range of analite concentration between 5 to 50 m mol L ?¹, the behavior is linear and the sensibility found was of 20,3 mA cm?² (mol L?¹?¹, presenting reproducibility confirming the nickel hydroxide electrodes utilization for the determination of urea.