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Sample records for all-solid photonic bandgap

  1. Fabrication and characterization of an all-solid tellurite-phosphate photonic bandgap fiber.

    Science.gov (United States)

    Cheng, Tonglei; Sakai, Yukiko; Suzuki, Takenobu; Ohishi, Yasutake

    2015-05-01

    We present an all-solid tellurite-phosphate photonic bandgap fiber (PBGF) with two layers of high-index rods (TeO2-Li2O-WO3-MoO3-Nb2O5, TLWMN) in the cladding (TeO2-ZnO-Li2O-K2O-Al2O3-P2O5, TZLKAP). TLWMN and TZLKAP glasses have good compatibility for fabricating the all-solid PBGF. Photonic bandgap (PBG) properties are calculated by the plane wave expansion method (PWM), and the results agree well with the measured transmission spectrum. Furthermore, the modal field patterns are measured at ∼1300 and 1520 nm, respectively. The light is confined to the core at ∼1300  nm and lost in the cladding at ∼1520  nm, which match well with the calculated modal field intensities.

  2. All-PM monolithic fs Yb-fiber laser, dispersion-managed with all-solid photonic bandgap fiber

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2009-01-01

    All-in-fiber SESAM-modelocked self-starting fiber laser is demonstrated. Cavity dispersion is managed by a spliced-in PM all-solid photonic bandgap fiber. The laser directly delivers 1.25 nJ pulses of 280 fs duration.......All-in-fiber SESAM-modelocked self-starting fiber laser is demonstrated. Cavity dispersion is managed by a spliced-in PM all-solid photonic bandgap fiber. The laser directly delivers 1.25 nJ pulses of 280 fs duration....

  3. Polarizing Ytterbium-Doped all-Solid Photonic Bandgap Fiber with 1150 micrometers2 Effective Mode Area

    Science.gov (United States)

    2015-02-11

    RESPONSIBLE PERSON 19b. TELEPHONE NUMBER Liang Dong Fanting Kong,, Guancheng Gu,, Thomas W. Hawkins ,, Joshua Parsons, Maxwell Jones,, Christopher...Dunn,, Monica T. Kalichevsky-Dong,, Benjamin Pulford,, Iyad Dajani,, Kunimasa Saitoh,, Stephen P. Palese,, Eric Cheung,, Liang Dong c. THIS PAGE The...ytterbium-doped all-solid photonic bandgap fiber with ~1150µm2 effective mode area Fanting Kong,1,* Guancheng Gu,1 Thomas W. Hawkins ,1 Joshua Parsons

  4. Tailoring Nd3+ emission spectrum by a neodymium-doped tellurite all-solid photonic bandgap fiber

    Science.gov (United States)

    Tong, Hoang Tuan; Demichi, Daisuke; Suzuki, Takenobu; Ohishi, Yasutake

    2018-02-01

    A tellurite all-solid photonic bandgap fiber (ASPBF) whose cladding consists of 60 high-index rods arranged periodically around a central core was successfully fabricated. The diameter of high-index rod was about 5.0 μm and the distance between the center of two adjacent high-index rods was approximately 8.0 μm. The high-index rod was made of the TeO2-Li2O-WO3-MoO3-Nb2O5 (TLWMN) glass, the cladding was made of the TeO2-ZnO-Na2O-La2O3 (TZNL) glass as the background glass material and the central core was made of TZNL glass doped with 0.5 wt% of Nd2O3. A supercontinuum light from 0.6 to 2.4 μm was coupled into the core of fiber which is 2.2 cm long to measure its transmission spectrum. High transmission bands were obtained in the vicinity of 0.75 and 1.3 μm but the transmission was suppressed in the wavelength range from 1.0 to 1.06 μm. When a titanium∶Sapphire laser source at 0.75 μm was used, the emission spectrum was obtained with two peaks at 1.06 and 1.33 μm which are attributed to the 4F3/2->4I11/2 and 4F3/2->4I13/2 transitions of Nd3+ ion, respectively. The intensities of those emission peaks were compared with those obtained from a bulk glass having the same doping concentration of Nd3+. The results showed that by using tellurite ASPBF, the intensity of the 1.06-μm emission was suppressed by one-twelfth but the intensity of the 1.33-μm emission was maintained. This feature is very advantageous to filter out the 1.06-μm emission of Nd3+ ion in order to realize practical amplifier devices at 1.3 μm.

  5. Photonic Bandgap (PBG) Shielding Technology

    Science.gov (United States)

    Bastin, Gary L.

    2007-01-01

    Photonic Bandgap (PBG) shielding technology is a new approach to designing electromagnetic shielding materials for mitigating Electromagnetic Interference (EM!) with small, light-weight shielding materials. It focuses on ground planes of printed wiring boards (PWBs), rather than on components. Modem PSG materials also are emerging based on planar materials, in place of earlier, bulkier, 3-dimensional PBG structures. Planar PBG designs especially show great promise in mitigating and suppressing EMI and crosstalk for aerospace designs, such as needed for NASA's Constellation Program, for returning humans to the moon and for use by our first human visitors traveling to and from Mars. Photonic Bandgap (PBG) materials are also known as artificial dielectrics, meta-materials, and photonic crystals. General PBG materials are fundamentally periodic slow-wave structures in I, 2, or 3 dimensions. By adjusting the choice of structure periodicities in terms of size and recurring structure spacings, multiple scatterings of surface waves can be created that act as a forbidden energy gap (i.e., a range of frequencies) over which nominally-conductive metallic conductors cease to be a conductor and become dielectrics. Equivalently, PBG materials can be regarded as giving rise to forbidden energy gaps in metals without chemical doping, analogous to electron bandgap properties that previously gave rise to the modem semiconductor industry 60 years ago. Electromagnetic waves cannot propagate over bandgap regions that are created with PBG materials, that is, over frequencies for which a bandgap is artificially created through introducing periodic defects

  6. Actively doped solid core Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Broeng, Jes; Olausson, Christina Bjarnal Thulin; Lyngsøe, Jens Kristian

    2010-01-01

    Solid photonic bandgap fibers offer distributed spectral filtering with extraordinary high suppression. This opens new possibilities of artificially tailoring the gain spectrum of fibers. We present record-performance of such fibers and outline their future applications....

  7. Monolithic all-PM femtosecond Yb-doped fiber laser using photonic bandgap fibers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2009-01-01

    We present a monolithic Yb fiber laser, dispersion managed by an all-solid photonic bandgap fiber, and pulse compressed in a hollow-core photonic crystal fiber. The laser delivers 9 nJ, 275-fs long pulses at 1035 nm.......We present a monolithic Yb fiber laser, dispersion managed by an all-solid photonic bandgap fiber, and pulse compressed in a hollow-core photonic crystal fiber. The laser delivers 9 nJ, 275-fs long pulses at 1035 nm....

  8. Advances in photonic bandgap fiber functionality

    DEFF Research Database (Denmark)

    Lyngsøe, Jens Kristian

    In order to take advantage of the many intriguing optical properties of photonic bandgap fibers, there are some technological challenges that have to be addressed. Among other things this includes transmission loss and the fibers ability to maintain field polarization. The work presented in this ......In order to take advantage of the many intriguing optical properties of photonic bandgap fibers, there are some technological challenges that have to be addressed. Among other things this includes transmission loss and the fibers ability to maintain field polarization. The work presented...

  9. Liquid Crystal photonic Bandgap Fiber Devices

    DEFF Research Database (Denmark)

    Wei, Lei

    In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure. The prese......In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure...... of each LCPBG fiber. Finally, the applications for LCPBG fiber devices based on the on-chip platform design have been demonstrated in realizing microwave true-time delay and creating an electrically tunable fiber laser. Referatet mailes...

  10. Multidimensional microstructured photonic device based on all-solid waveguide array fiber and magnetic fluid

    Directory of Open Access Journals (Sweden)

    Miao Yinping

    2016-11-01

    Full Text Available An all-solid waveguide array fiber (WAF is one kind of special microstructured optical fiber in which the higher-index rods are periodically distributed in a low-index silica host to form the transverse two-dimensional photonic crystal. In this paper, one kind of multidimensional microstructured optical fiber photonic device is proposed by using electric arc discharge method to fabricate periodic tapers along the fiber axis. By tuning the applied magnetic field intensity, the propagation characteristics of the all-solid WAF integrated with magnetic fluid are periodically modulated in both radial and axial directions. Experimental results show that the wavelength changes little while the transmission loss increases for an applied magnetic field intensity range from 0 to 500 Oe. The magnetic field sensitivity is 0.055 dB/Oe within the linear range from 50 to 300 Oe. Meanwhile, the all-solid WAF has very similar thermal expansion coefficient for both high- and low-refractive index glasses, and thermal drifts have a little effect on the mode profile. The results show that the temperature-induced transmission loss is <0.3 dB from 26°C to 44°C. Further tuning coherent coupling of waveguides and controlling light propagation, the all-solid WAF would be found great potential applications to develop new micro-nano photonic devices for optical communications and optical sensing applications.

  11. Two-dimensional Kagome photonic bandgap waveguide

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Søndergaard, Thomas; Libori, Stig E. Barkou

    2000-01-01

    The transverse-magnetic photonic-bandgap-guidance properties are investigated for a planar two-dimensional (2-D) Kagome waveguide configuration using a full-vectorial plane-wave-expansion method. Single-moded well-localized low-index guided modes are found. The localization of the optical modes...... is investigated with respect to the width of the 2-D Kagome waveguide, and the number of modes existing for specific frequencies and waveguide widths is mapped out....

  12. Electrically tunable liquid crystal photonic bandgap fiber laser

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

    2010-01-01

    We demonstrate electrical tunability of a fiber laser by using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an al...

  13. All-solid-state deep ultraviolet laser for single-photon ionization mass spectrometry.

    Science.gov (United States)

    Yuan, Chengqian; Liu, Xianhu; Zeng, Chenghui; Zhang, Hanyu; Jia, Meiye; Wu, Yishi; Luo, Zhixun; Fu, Hongbing; Yao, Jiannian

    2016-02-01

    We report here the development of a reflectron time-of-flight mass spectrometer utilizing single-photon ionization based on an all-solid-state deep ultraviolet (DUV) laser system. The DUV laser was achieved from the second harmonic generation using a novel nonlinear optical crystal KBe2BO3F2 under the condition of high-purity N2 purging. The unique property of this laser system (177.3-nm wavelength, 15.5-ps pulse duration, and small pulse energy at ∼15 μJ) bears a transient low power density but a high single-photon energy up to 7 eV, allowing for ionization of chemicals, especially organic compounds free of fragmentation. Taking this advantage, we have designed both pulsed nanospray and thermal evaporation sources to form supersonic expansion molecular beams for DUV single-photon ionization mass spectrometry (DUV-SPI-MS). Several aromatic amine compounds have been tested revealing the fragmentation-free performance of the DUV-SPI-MS instrument, enabling applications to identify chemicals from an unknown mixture.

  14. Polarization splitter based on interference effects in all-solid photonic crystal fibers.

    Science.gov (United States)

    Mao, Dong; Guan, Chunying; Yuan, Libo

    2010-07-01

    We propose a novel kind of polarization splitter in all-solid photonic crystal fibers based on the mode interference effects. Both the full-vector finite-element method and the semi-vector three-dimensional beam propagation method are employed to design and analyze the characteristics of the splitter. Numerical simulations show that x-polarized and y-polarized modes are split entirely along with 6.8 mm long propagation. An extinction ratio of more than 20 dB and a crosstalk of less than -20 dB are obtained within the wavelength range of 1.541-1.556 microm. The extinction ratio and the crosstalk at 1.55 microm are 28.9 and -29.0 dB for x polarization, while the extinction ratio and the crosstalk at 1.55 microm are 29.9 and -29.8 dB for y polarization, respectively.

  15. Micromachined millimeter-wave photonic band-gap crystals

    International Nuclear Information System (INIS)

    Oezbay, E.; Michel, E.; Tuttle, G.; Biswas, R.; Sigalas, M.; Ho, K.

    1994-01-01

    We have developed a new technique for fabricating three-dimensional photonic band-gap crystals. Our method utilizes an orderly stacking of micromachined (110) silicon wafers to build the periodic structure. A structure with a full three-dimensional photonic band gap centered near 100 GHz was measured, with experimental results in good agreement with theoretical predictions. This basic approach described should be extendable to build structures with photonic band-gap frequencies ranging from 30 GHz to 3 THz

  16. Metallic photonic band-gap materials

    International Nuclear Information System (INIS)

    Sigalas, M.M.; Chan, C.T.; Ho, K.M.; Soukoulis, C.M.

    1995-01-01

    We calculate the transmission and absorption of electromagnetic waves propagating in two-dimensional (2D) and 3D periodic metallic photonic band-gap (PBG) structures. For 2D systems, there is substantial difference between the s- and p-polarized waves. The p-polarized waves exhibit behavior similar to the dielectric PBG's. But, the s-polarized waves have a cutoff frequency below which there are no propagating modes. For 3D systems, the results are qualitatively the same for both polarizations but there are important differences related to the topology of the structure. For 3D structures with isolated metallic scatterers (cermet topology), the behavior is similar to that of the dielectric PBG's, while for 3D structures with the metal forming a continuous network (network topology), there is a cutoff frequency below which there are no propagating modes. The systems with the network topology may have some interesting applications for frequencies less than about 1 THz where the absorption can be neglected. We also study the role of the defects in the metallic structures

  17. Transmission properties of hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Falk, Charlotte Ijeoma; Hald, Jan; Petersen, Jan C.

    2010-01-01

    Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers.......Variations in optical transmission of four types of hollow-core photonic bandgap fibers are measured as a function of laser frequency. These variations influence the potential accuracy of gas sensors based on molecular spectroscopy in hollow-core fibers....

  18. Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Wu; He, Sailing

    2012-01-01

    We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress-induced ...

  19. All-solid-state cavity QED using Anderson-localized modes in disordered photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lodahl, Peter; Sapienza, Luca; Nielsen, Henri Thyrrestrup

    2010-01-01

    We employ Anderson-localized modes in deliberately disordered photonic crystal waveguides to confine light and enhance the interaction with matter. A 15-fold enhancement of the decay rate of a single quantum dot is observed meaning that 94% of the emitted single photons are coupled to an Anderson...

  20. Optical devices based on liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard

    2005-01-01

    the waveguiding mechanism of LC filled PCFs. The principle of tunable fibers based on LCs is thereafter discussed and an alignment and coating study of LC in capillaries is presented. Next, the Liquid Crystal Photonic BandGap (LCPBG) fiber is presented and the waveguiding mechanism is analyzed through plane...... hole. The presence of a LC in the holes of the PCF transforms the fiber from a Total Internal Reflection (TIR) guiding type into a Photonic BandGap (PBG) guiding type, where light is confined to the silica core by coherent scattering from the LC-billed holes. The high dielectric and optical anisotropy...

  1. Water-Dependent Photonic Bandgap in Silica Artificial Opals

    OpenAIRE

    Gallego-Gomez, Francisco; Blanco, Alvaro; Canalejas-Tejero, Victor; Lopez, Cefe

    2011-01-01

    Some characteristics of silica-based structuresa-like the photonic properties of artificial opals formed by silica spheresa-can be greatly affected by the presence of adsorbed water. The reversible modification of the water content of an opal is investigated here by moderate heating (below 300 °C) and measuring in situ the changes in the photonic bandgap. Due to reversible removal of interstitial water, large blueshifts of 30 nm and a bandgap narrowing of 7% are observed. The latter is partic...

  2. Compact electrically controlled broadband liquid crystal photonic bandgap fiber polarizer

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm.......An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm....

  3. Design of photonic bandgap fibers by topology optimization

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole; Feurer, Thomas

    2010-01-01

    A method based on topology optimization is presented to design the cross section of hollow-core photonic bandgap fibers for minimizing energy loss by material absorption. The optical problem is modeled by the timeharmonic wave equation and solved with the finite element program Comsol Multiphysics...

  4. Optically controlled photonic bandgap structures for microstrip circuits

    International Nuclear Information System (INIS)

    Cadman, Darren Arthur

    2003-01-01

    This thesis is concerned with the optical control of microwave photonic bandgap circuits using high resistivity silicon. Photoconducting processes that occur within silicon are investigated. The influence of excess carrier density on carrier mobility and lifetime is examined. In addition, electron-hole pair recombination mechanisms (Shockley-Read-Hall, Auger, radiative and surface) are investigated. The microwave properties of silicon are examined, in particular the variation of silicon reflectivity with excess carrier density. Filtering properties of microstrip photonic bandgap structures and how they may be controlled optically are studied. A proof-of-concept microstrip photonic bandgap structure with optical control is designed, simulated and measured. With no optical illumination incident upon the silicon, the microstrip photonic bandgap structure's filtering properties are well-defined; a 3dB stopband width of 2.6GHz, a 6dB bandwidth of 2GHz and stopband depth of -11.6dB at the centre frequency of 9.9GHz. When the silicon is illuminated, the structure's filtering properties are suppressed. Under illumination the experimental results display an increase in S 21 of 6.5dB and a reduction in S 11 of more than 10dB at 9.9GHz. A comparison of measured and simulated results reveal that the photogenerated excess carrier density is between 4 x 10 15 cm -3 and 1.1 x 10 16 cm -3 . (author)

  5. Infrared photonic bandgap materials and structures

    Science.gov (United States)

    Sundaram, S. K.; Keller, P. E.; Riley, B. J.; Martinez, J. E.; Johnson, B. R.; Allen, P. J.; Saraf, L. V.; Anheier, N. C., Jr.; Liau, F.

    2006-02-01

    Three-dimensional periodic dielectric structure can be described by band theory, analogous to electron waves in a crystal. Photonic band gap (PBG) structures were introduced in 1987. The PBG is an energy band in which optical modes, spontaneous emission, and zero-point fluctuations are all absent. It was first theoretically predicted that a three-dimensional photonic crystal could have a complete band gap. E. Yablonovitch built the first three-dimensional photonic crystal (Yablonovite) on microwave length scale, with a complete PBG. In nature, photonic crystals occur as semiprecious opal and the microscopic structures on the wings of some tropical butterflies, which are repeating structures (PBG structure/materials) that inhibit the propagation of some frequencies of light. Pacific Northwest National Laboratory (PNNL) has been developing tunable (between 3.5 and 16 μm) quantum cascade lasers (QCL), chalcogenides, and all other components for an integrated approach to chemical sensing. We have made significant progress in modeling and fabrication of infrared photonic band gap (PBG) materials and structures. We modeled several 2-D designs and defect configurations. Transmission spectra were computed by the Finite Difference Time Domain Method (with FullWAVE TM). The band gaps were computed by the Plane Wave Expansion Method (with BandSOLVE TM). The modeled designs and defects were compared and the best design was identified. On the experimental front, chalcogenide glasses were used as the starting materials. As IIS 3, a common chalcogenide, is an important infrared (IR) transparent material with a variety of potential applications such as IR sensors, waveguides, and photonic crystals. Wet-chemical lithography has been extended to PBG fabrication and challenges identified. An overview of results and challenges will be presented.

  6. Photonic bandgap narrowing in conical hollow core Bragg fibers

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, Fahri Emre; Yildirim, Adem; Kanik, Mehmet [UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey); Bayindir, Mehmet, E-mail: bayindir@nano.org.tr [UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey); Department of Physics, Bilkent University, 06800 Ankara (Turkey)

    2014-08-18

    We report the photonic bandgap engineering of Bragg fibers by controlling the thickness profile of the fiber during the thermal drawing. Conical hollow core Bragg fibers were produced by thermal drawing under a rapidly alternating load, which was applied by introducing steep changes to the fiber drawing speed. In conventional cylindrical Bragg fibers, light is guided by omnidirectional reflections from interior dielectric mirrors with a single quarter wave stack period. In conical fibers, the diameter reduction introduced a gradient of the quarter wave stack period along the length of the fiber. Therefore, the light guided within the fiber encountered slightly smaller dielectric layer thicknesses at each reflection, resulting in a progressive blueshift of the reflectance spectrum. As the reflectance spectrum shifts, longer wavelengths of the initial bandgap cease to be omnidirectionally reflected and exit through the cladding, which narrows the photonic bandgap. A narrow transmission bandwidth is particularly desirable in hollow waveguide mid-infrared sensing schemes, where broadband light is coupled to the fiber and the analyte vapor is introduced into the hollow core to measure infrared absorption. We carried out sensing simulations using the absorption spectrum of isopropyl alcohol vapor to demonstrate the importance of narrow bandgap fibers in chemical sensing applications.

  7. Quantum state propagation in linear photonic bandgap structures

    International Nuclear Information System (INIS)

    Severini, S; Tricca, D; Sibilia, C; Bertolotti, M; Perina, Jan

    2004-01-01

    In this paper we investigate the propagation of a generic quantum state in a corrugated waveguide, which reproduces a photonic bandgap structure. We find the conditions that assure the outcoming state to preserve the quantum properties of the incoming state. Then, focusing on a particular quantum state (realized by two counter-propagating coherent states), we study the possibility of preserving the quantum properties of this particular double coherent state even in the presence of absorption phenomena during propagation in the structure

  8. Silica-air photonic crystal fiber design that permits waveguiding by a true photonic bandgap effect

    DEFF Research Database (Denmark)

    Barkou, Stig Eigil; Broeng, Jes; Bjarklev, Anders Overgaard

    1999-01-01

    A theoretical investigation of a novel type of optical fiber is presented. The operation of the fiber relies entirely on wave guidance through the photonic bandgap effect and not on total internal reflection, thereby distinguishing that fiber from all other known fibers, including recently studied...... photonic crystal fibers. The novel fiber has a central low-index core region and a cladding consisting of a silica background material with air holes situated within a honeycomb lattice structure. We show the existence of photonic bandgaps for the silica–air cladding structure and demonstrate how light can...... be guided at the central low-index core region for a well-defined frequency that falls inside the photonic bandgap region of the cladding structure....

  9. Temperature-modified photonic bandgap in colloidal photonic crystals fabricated by vinyl functionalized silica spheres

    International Nuclear Information System (INIS)

    Deng Tiansong; Zhang Junyan; Zhu Kongtao; Zhang Qifeng; Wu Jinlei

    2011-01-01

    Graphical abstract: A thermal annealing procedure was described for fine modifying the photonic bandgap properties of colloidal photonic crystals, which were self-assembled from vinyl-functionalized silica spheres by a gravity sedimentation process. Highlights: → We described a thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals. → The position of its stop band had more than 25% blue shift by annealing the sample from 60 to 600 deg. C. → The annealing temperature and the Bragg peak values have a linear relationship in the 120-440 deg. C range. → The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals. - Abstract: A thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals was described. The colloidal photonic crystals were assembled from monodisperse vinyl functionalized silica spheres by a gravity sedimentation process. The samples diffract light following Bragg's law combined with Snell's law. By annealing the sample at temperatures in the range of 60-600 deg. C, the position of its stop band shifted from 943 to 706 nm. It had more than 25% blue shift. In addition, the annealing temperature and the Bragg peak values have a linear relationship in the 120-440 deg. C range. Fourier transform infrared (FT-IR) spectra and thermo-gravimetric analysis (TGA) curves of vinyl functionalized silica spheres confirmed the above results. The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals.

  10. Photonic bandgap structure of 3-D fcc silica nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Y. K.; Ha, N. Y.; Hwang, Ji Soo; Chang, H. J.; Wu, J. W. [Dept. of Physics, Ewha Womans University, Seoul (Korea, Republic of)

    2002-07-01

    Photonic crystal is an artificial optical material with a periodic dielectric potential, hence exhibiting a bandgap for a propagating electromagnetic wave. We fabricated crystal possessing 3-D fcc opal structure from silica nanospheres. The crystals are self-assembled on a flat glass by evaporating the solvent in the nanosphere suspension at the room temperature. The suspension consists of silica nanospheres with a diameter of 200 nm. The microscopic arrangement of nanospheres is identified by a scanning electron microscope, the resulting structure being fcc.Transmission spectrum of the fabricated photonic crystal in the visible and near-infrared regions is measured at different incident angles to find the distinct Bragg peaks, analysis of which further confirmed the fcc structure of the photonic crystal. From the optical microscopic image, we find that the opal domain varies from 30 μm to 125 μm in size. In order to relate the observed Bragg peaks with the microscopic arrangement of silica nanospheres, we introduced the scalar wave approximation, where the electric field in the medium is treated as a scalar rather than a vector quantity. It is found that the theoretical prediction of the position of bandgap is in a good agreement with the experimental measurement.

  11. Photonic bandgap structure of 3-D fcc silica nanospheres

    International Nuclear Information System (INIS)

    Woo, Y. K.; Ha, N. Y.; Hwang, Ji Soo; Chang, H. J.; Wu, J. W.

    2002-01-01

    Photonic crystal is an artificial optical material with a periodic dielectric potential, hence exhibiting a bandgap for a propagating electromagnetic wave. We fabricated crystal possessing 3-D fcc opal structure from silica nanospheres. The crystals are self-assembled on a flat glass by evaporating the solvent in the nanosphere suspension at the room temperature. The suspension consists of silica nanospheres with a diameter of 200 nm. The microscopic arrangement of nanospheres is identified by a scanning electron microscope, the resulting structure being fcc.Transmission spectrum of the fabricated photonic crystal in the visible and near-infrared regions is measured at different incident angles to find the distinct Bragg peaks, analysis of which further confirmed the fcc structure of the photonic crystal. From the optical microscopic image, we find that the opal domain varies from 30 μm to 125 μm in size. In order to relate the observed Bragg peaks with the microscopic arrangement of silica nanospheres, we introduced the scalar wave approximation, where the electric field in the medium is treated as a scalar rather than a vector quantity. It is found that the theoretical prediction of the position of bandgap is in a good agreement with the experimental measurement.

  12. Electromagnetically induced photonic bandgap in hot Cs atoms

    International Nuclear Information System (INIS)

    Li, D. W.; Zhang, L.; Su, X. M.; Zhuo, Z. C.; Kim, J. B

    2010-01-01

    Three-level Λ-type thermal Cs atoms are used to demonstrate the phenomenon of a photonic bandgap induced by quantum coherence with a standing wave (SW). We observed the transmitted signals of probe field driven by several kinds of SW, which are formed by a strong forward-traveling field and a backward-traveling field when a mirror reflects the forward-traveling beam. Considering Doppler inhomogeneous broadenings with a SW drive, we employ Fourier transformation to solve density-matrix equations for simulation results. The simulation results are found to be consistent with the experimental results.

  13. Mode Division Multiplexing Exploring Hollow-Core Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Xu, Jing; Lyngso, Jens Kristian; Leick, Lasse

    2013-01-01

    We review our recent exploratory investigations on mode division multiplexing using hollow-core photonic bandgap fibers (HC-PBGFs). Compared with traditional multimode fibers, HC-PBGFs have several attractive features such as ultra-low nonlinearities, low-loss transmission window around 2 µm etc....... After having discussed the potential and challenges of using HC-PBGFs as transmission fibers for mode multiplexing applications, we will report a number of recent proof-of-concept results obtained in our group using direct detection receivers. The first one is the transmission of two 10.7 Gbit/s non...

  14. Soliton formation in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper

    2009-01-01

    of an approximate scaling relation is tested. It is concluded that compression of input pulses of several ps duration and sub-MW peak power can lead to a formation of solitons with ∼100 fs duration and multi-megawatt peak powers. The dispersion slope of realistic hollow-core fibers appears to be the main obstacle......The formation of solitons upon compression of linearly chirped pulses in hollow-core photonic bandgap fibers is investigated numerically. The dependence of soliton duration on the chirp and power of the input pulse and on the dispersion slope of the fiber is investigated, and the validity...

  15. True photonic band-gap mode-control in VCSEL structures

    DEFF Research Database (Denmark)

    Romstad, F.; Madsen, M.; Birkedal, Dan

    2003-01-01

    Photonic band-gap mode confinement in novel nano-structured large area VCSEL structures is confirmed by the amplified spontaneous emission spectrum. Both guide and anti-guide VCSEL structures are experimentally characterised to verify the photonic band-gap effect.......Photonic band-gap mode confinement in novel nano-structured large area VCSEL structures is confirmed by the amplified spontaneous emission spectrum. Both guide and anti-guide VCSEL structures are experimentally characterised to verify the photonic band-gap effect....

  16. Phase modulation and structural effects in a D-shaped all-solid photonic crystal fiber surface plasmon resonance sensor.

    Science.gov (United States)

    Tan, Zhixin; Hao, Xin; Shao, Yonghong; Chen, Yuzhi; Li, Xuejin; Fan, Ping

    2014-06-16

    We numerically investigate a D-shaped fiber surface plasmon resonance sensor based on all-solid photonic crystal fiber (PCF) with finite element method. In the side-polished PCF sensor, field leakage is guided to penetrate through the gap between the rods, causing a pronounced phase modulation in the deep polishing case. Taking advantage of these amplified phase shifts, a high-performance fiber sensor design is proposed. The significant enhancements arising from this new sensor design should lift the performance of the fiber SPR sensor into the range capable of detecting a wide range of biochemical interactions, which makes it especially attractive for many in vivo and in situ bioanalysis applications. Several parameters which influence the field leakage, such as the polishing position, the pitch of the PCF, and the rod diameter, are inspected to evaluate their impacts. Furthermore, we develop a mathematical model to describe the effects of varying the structural parameters of a D-shaped PCF sensor on the evanescent field and the sensor performance.

  17. Electrically pumped edge-emitting photonic bandgap semiconductor laser

    Science.gov (United States)

    Lin, Shawn-Yu; Zubrzycki, Walter J.

    2004-01-06

    A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

  18. Waveguidance by the photonic bandgap effect in optical fibres

    DEFF Research Database (Denmark)

    Broeng, Jes; Søndergaard, Thomas; Barkou, Stig Eigil

    1999-01-01

    Photonic crystals form a new class of intriguing building blocks to be utilized in future optoelectronics and electromagnetics. One of the most exciting possiblilties offered by phtonic crystals is the realization of new types of electromagnetic waveguides. In the optical domain, the most mature...... technology for such photonic bandgap (PBG) waveguides is in optical fibre configurations. These new fibres can be classified in a fundamentally different way to all optical waveguides and possess radically different guiding properties due to PBG guidance, as opposed to guidance by total internal refelction....... In this paper we summarize and review our theoretical work demonstrating the underlying physical principles of PBG guiding optical fibres and discuss some of their unique waveguiding properties....

  19. Water-dependent photonic bandgap in silica artificial opals.

    Science.gov (United States)

    Gallego-Gómez, Francisco; Blanco, Alvaro; Canalejas-Tejero, Victor; López, Cefe

    2011-07-04

    Some characteristics of silica--based structures-like the photonic properties of artificial opals formed by silica spheres--can be greatly affected by the presence of adsorbed water. The reversible modification of the water content of an opal is investigated here by moderate heating (below 300 °C) and measuring in situ the changes in the photonic bandgap. Due to reversible removal of interstitial water, large blueshifts of 30 nm and a bandgap narrowing of 7% are observed. The latter is particularly surprising, because water desorption increases the refractive index contrast, which should lead instead to bandgap broadening. A quantitative explanation of this experiment is provided using a simple model for water distribution in the opal that assumes a nonclose-packed fcc structure. This model further predicts that, at room temperature, about 50% of the interstitial water forms necks between nearest-neighbor spheres, which are separated by 5% of their diameter. Upon heating, dehydration predominantly occurs at the sphere surfaces (in the opal voids), so that above 65 °C the remaining water resides exclusively in the necks. A near-close-packed fcc arrangement is only achieved above 200 °C. The high sensitivity to water changes exhibited by silica opals, even under gentle heating of few degrees, must be taken into account for practical applications. Remarkably, accurate control of the distance between spheres--from 16 to 1 nm--is obtained with temperature. In this study, novel use of the optical properties of the opal is made to infer quantitative information about water distribution within silica beads and dehydration phenomena from simple reflection spectra. Taking advantage of the well-defined opal morphology, this approach offers a simple tool for the straightforward investigation of generic adsorption-desorption phenomena, which might be extrapolated to many other fields involving capillary condensation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGa

  20. Opal-based photonic crystal with double photonic bandgap structure

    Science.gov (United States)

    Romanov, S. G.; Yates, H. M.; Pemble, M. E.; DeLa Rue, R. M.

    2000-09-01

    The interior surfaces of one part of a piece of artificial opal have been coated with GaP so that the remaining part of the opal crystal remains empty, thus forming a photonic heterostructure. Two Bragg resonances have been observed in the optical transmission and reflectance spectra. These two resonances were found to behave differently with changes in the polarization of the incident light and the angle of propagation of the light with respect to the (111) planes of opal. Depolarization of the light was observed to occur most effectively at frequencies within the stop-bands, apparently due to the re-coupling of the propagating electromagnetic wave to a different system of eigenmodes when it crosses the interface separating two parts of the double photonic crystal.

  1. Quasiperiodic one-dimensional photonic crystals with adjustable multiple photonic bandgaps.

    Science.gov (United States)

    Vyunishev, Andrey M; Pankin, Pavel S; Svyakhovskiy, Sergey E; Timofeev, Ivan V; Vetrov, Stepan Ya

    2017-09-15

    We propose an elegant approach to produce photonic bandgap (PBG) structures with multiple photonic bandgaps by constructing quasiperiodic photonic crystals (QPPCs) composed of a superposition of photonic lattices with different periods. Generally, QPPC structures exhibit both aperiodicity and multiple PBGs due to their long-range order. They are described by a simple analytical expression, instead of quasiperiodic tiling approaches based on substitution rules. Here we describe the optical properties of QPPCs exhibiting two PBGs that can be tuned independently. PBG interband spacing and its depth can be varied by choosing appropriate reciprocal lattice vectors and their amplitudes. These effects are confirmed by the proof-of-concept measurements made for the porous silicon-based QPPC of the appropriate design.

  2. Terahertz spectroscopy of three-dimensional photonic band-gap crystals

    International Nuclear Information System (INIS)

    Oezbay, E.; Michel, E.; Tuttle, G.; Biswas, R.; Ho, K.M.; Bostak, J.; Bloom, D.M.

    1994-01-01

    We have fabricated and built three-dimensional photonic band-gap crystals with band-gap frequencies larger than 500 GHz. We built the crystals by stacking micromachined (110) silicon wafers. The transmission and dispersion characteristics of the structures were measured by an all-electronic terahertz spectroscopy setup. The experimental results were in good agreement with theoretical calculations. To our knowledge, our new crystal has the highest reported photonic band-gap frequency

  3. Analysis of photonic band-gap structures in stratified medium

    DEFF Research Database (Denmark)

    Tong, Ming-Sze; Yinchao, Chen; Lu, Yilong

    2005-01-01

    in electromagnetic and microwave applications once the Maxwell's equations are appropriately modeled. Originality/value - The method validates its values and properties through extensive studies on regular and defective 1D PBG structures in stratified medium, and it can be further extended to solving more......Purpose - To demonstrate the flexibility and advantages of a non-uniform pseudo-spectral time domain (nu-PSTD) method through studies of the wave propagation characteristics on photonic band-gap (PBG) structures in stratified medium Design/methodology/approach - A nu-PSTD method is proposed...... in solving the Maxwell's equations numerically. It expands the temporal derivatives using the finite differences, while it adopts the Fourier transform (FT) properties to expand the spatial derivatives in Maxwell's equations. In addition, the method makes use of the chain-rule property in calculus together...

  4. Thermal tunability of photonic bandgaps in liquid crystal infiltrated microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wei, Lei; Alkeskjold, Thomas Tanggaard

    2009-01-01

    We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used to demons......We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used...... to demonstrate that both signs of the thermal tunability of the bandgaps are possible. The useful bandgaps are ultimately bounded to the visible range by the transparency window of the polymer....

  5. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  6. A Polarization Maintaining Filter based on a Liquid-Crystal-Photonic-Bandgap-Fiber

    DEFF Research Database (Denmark)

    Scolari, Lara; Olausson, Christina Bjarnal Thulin; Turchinovich, Dmitry

    2008-01-01

    A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm.......A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm....

  7. Optical tuning of photonic bandgaps in dye-doped nematic liquid crystal photonic crystal fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard; Hermann, David Sparre

    2005-01-01

    An all-optical modulator is demonstrated, which utilizes a pulsed 532 nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. In order to investigate the time response of the LCPBG fiber device, a low-power CW probe...... laser was coupled into the fiber together with the pulsed pump laser of 2.3 mW and we have demonstrated a modulation frequency of up to 2 kHz....

  8. Complete three-dimensional photonic bandgap in a simple cubic structure

    International Nuclear Information System (INIS)

    Lin, Shawn-Yu; Fleming, J. G.; Lin, Robin; Sigalas, M. M.; Biswas, R.; Ho, K. M.

    2001-01-01

    The creation of a three-dimensional (3D) photonic crystal with simple cubic (sc) symmetry is important for applications in the signal routing and 3D waveguiding of light. With a simple stacking scheme and advanced silicon processing, a 3D sc structure was constructed from a 6-in. silicon wafer. The sc structure is experimentally shown to have a complete 3D photonic bandgap in the infrared wavelength. The finite size effect is also observed, accounting for a larger absolute photonic bandgap

  9. Resonance fluorescence spectrum in a two-band photonic bandgap crystal

    Science.gov (United States)

    Lee, Ray-Kuang; Lai, Yinchieh

    2003-05-01

    Steady state resonance fluorescence spectra from a two-level atom embedded in a photonic bandgap crystal and resonantly driven by a classical pump light are calculated. The photonic crystal is considered to be with a small bandgap which is in the order of magnitude of the Rabi frequency and is modeled by the anisotropic two-band dispersion relation. Non-Markovian noises caused by the non-uniform distribution of photon density states near the photonic bandgap are taken into account by a new approach which linearizes the optical Bloch equations by using the Liouville operator expansion. Fluorescence spectra that only exhibit sidebands of the Mollow triplet are found, indicating that there is no coherent Rayleigh scattering process.

  10. Self-stabilization of a mode-locked femtosecond fiber laser using a photonic bandgap fiber

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2010-01-01

    We demonstrate a self-stabilization mechanism of a semiconductor saturable absorber mode-locked linearcavity Yb-doped fiber laser using an intracavity photonic bandgap fiber. This mechanism relies on the spectral shift of the laser pulses to a spectral range of higher anomalous dispersion...... and higher loss of the photonic bandgap fiber, as a reaction to the intracavity power buildup. This, in particular, results in a smaller cavity loss for the stably mode-locked laser, as opposed to the Q-switched mode-locking scenario. The laser provides stable 39–49 pJ pulses of around 230 fs duration at 29...

  11. Band structure of germanium carbides for direct bandgap silicon photonics

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, C. A., E-mail: cstephe3@nd.edu; Stillwell, R. A.; Wistey, M. A. [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); O' Brien, W. A. [Rigetti Quantum Computing, 775 Heinz Avenue, Berkeley, California 94710 (United States); Penninger, M. W. [Honeywell UOP, Des Plaines, Illinois 60016 (United States); Schneider, W. F. [Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Gillett-Kunnath, M. [Department of Chemistry, Syracuse University, Syracuse, New York 13244 (United States); Zajicek, J. [Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Yu, K. M. [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Kudrawiec, R. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2016-08-07

    Compact optical interconnects require efficient lasers and modulators compatible with silicon. Ab initio modeling of Ge{sub 1−x}C{sub x} (x = 0.78%) using density functional theory with HSE06 hybrid functionals predicts a splitting of the conduction band at Γ and a strongly direct bandgap, consistent with band anticrossing. Photoreflectance of Ge{sub 0.998}C{sub 0.002} shows a bandgap reduction supporting these results. Growth of Ge{sub 0.998}C{sub 0.002} using tetrakis(germyl)methane as the C source shows no signs of C-C bonds, C clusters, or extended defects, suggesting highly substitutional incorporation of C. Optical gain and modulation are predicted to rival III–V materials due to a larger electron population in the direct valley, reduced intervalley scattering, suppressed Auger recombination, and increased overlap integral for a stronger fundamental optical transition.

  12. Cavity quantum electrodynamics with three-dimensional photonic bandgap crystals

    NARCIS (Netherlands)

    Vos, Willem L.; Woldering, L.A.; Ghulinyan, M.; Pavesi, L.

    2015-01-01

    This paper is Chapter 8 of the book "Light Localisation and Lasing: Random and Pseudorandom Photonic Structures", edited by Mher Ghulinyan and Lorenzo Pavesi (Cambridge University Press, Cambridge, 2015). It provides an overview of much recent work on 3D photonic crystals with a complete photonic

  13. Stability and bandgaps of layered perovskites for one- and two-photon water splitting

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; García Lastra, Juan Maria; Hüser, Falco

    2013-01-01

    in the Ruddlesden–Popper phase of the layered perovskite structure. Based on screening criteria for the stability, bandgaps and band edge positions, we suggest 20 new materials for the light harvesting photo-electrode of a one-photon water splitting device and 5 anode materials for a two-photon device with silicon...... as photo-cathode. In addition, we explore a simple rule relating the bandgap of the perovskite to the number of octahedra in the layered structure and the B-metal ion. Finally, the quality of the GLLB-SC potential used to obtain the bandgaps, including the derivative discontinuity, is validated against G0W......0@LDA gaps for 20 previously identified oxides and oxynitrides in the cubic perovskite structure....

  14. Triple photonic band-gap structure dynamically induced in the presence of spontaneously generated coherence

    International Nuclear Information System (INIS)

    Gao Jinwei; Bao Qianqian; Wan Rengang; Cui Cuili; Wu Jinhui

    2011-01-01

    We study a cold atomic sample coherently driven into the five-level triple-Λ configuration for attaining a dynamically controlled triple photonic band-gap structure. Our numerical calculations show that three photonic band gaps with homogeneous reflectivities up to 92% can be induced on demand around the probe resonance by a standing-wave driving field in the presence of spontaneously generated coherence. All these photonic band gaps are severely malformed with probe reflectivities declining rapidly to very low values when spontaneously generated coherence is gradually weakened. The triple photonic band-gap structure can also be attained in a five-level chain-Λ system of cold atoms in the absence of spontaneously generated coherence, which however requires two additional traveling-wave fields to couple relevant levels.

  15. Photolithography of thick photoresist coating for electrically controlled liquid crystal photonic bandgap fibre devices

    DEFF Research Database (Denmark)

    Wei, Lei; Khomtchenko, Elena; Alkeskjold, Thomas Tanggaard

    2009-01-01

    Thick photoresist coating for electrode patterning in an anisotropically etched V-groove is investigated for electrically controlled liquid crystal photonic bandgap fibre devices. The photoresist step coverage at the convex corners is compared with and without soft baking after photoresist spin...

  16. Transmission properties of hollow-core photonic bandgap fibers in relation to molecular spectroscopy

    DEFF Research Database (Denmark)

    Falk, Charlotte Ijeoma; Hald, Jan; Petersen, Jan C.

    2010-01-01

    The transmission properties of five types of hollow-core photonic bandgap fibers (HC-PBFs) are characterized in the telecom wavelength range around 1:5 μm. The variations in optical transmission are measured as a function of laser frequency over a 2GHz scan range as well as a function of time over...

  17. Tunable polarisation-maintaining filter based on liquid crystal photonic bandgap fibre

    DEFF Research Database (Denmark)

    Scolari, Lara; Olausson, Christina Bjarnal Thulin; Weirich, Johannes

    2008-01-01

    A tunable and polarisation-maintaining all-in-fibre filter based on a liquid crystal photonic bandgap fibre is demonstrated. Its polarisation extinction ratio reaches 14 dB at 1550 nm wavelength. Its spectral tunability range spans over 250 nm in the temperature range 30–70°C. The measured...

  18. Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

    2011-01-01

    In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

  19. Effect of background dielectric on TE-polarized photonic bandgap of metallodielectric photonic crystals using Dirichlet-to-Neumann map method.

    Science.gov (United States)

    Sedghi, Aliasghar; Rezaei, Behrooz

    2016-11-20

    Using the Dirichlet-to-Neumann map method, we have calculated the photonic band structure of two-dimensional metallodielectric photonic crystals having the square and triangular lattices of circular metal rods in a dielectric background. We have selected the transverse electric mode of electromagnetic waves, and the resulting band structures showed the existence of photonic bandgap in these structures. We theoretically study the effect of background dielectric on the photonic bandgap.

  20. Enhanced Impurity-Free Intermixing Bandgap Engineering for InP-Based Photonic Integrated Circuits

    Science.gov (United States)

    Cui, Xiao; Zhang, Can; Liang, Song; Zhu, Hong-Liang; Hou, Lian-Ping

    2014-04-01

    Impurity-free intermixing of InGaAsP multiple quantum wells (MQW) using sputtering Cu/SiO2 layers followed by rapid thermal processing (RTP) is demonstrated. The bandgap energy could be modulated by varying the sputtering power and time of Cu, RTP temperature and time to satisfy the demands for lasers, modulators, photodetector, and passive waveguides for the photonic integrated circuits with a simple procedure. The blueshift of the bandgap wavelength of MQW is experimentally investigated on different sputtering and annealing conditions. It is obvious that the introduction of the Cu layer could increase the blueshift more greatly than the common impurity free vacancy disordering technique. A maximum bandgap blueshift of 172 nm is realized with an annealing condition of 750°C and 200s. The improved technique is promising for the fabrication of the active/passive optoelectronic components on a single wafer with simple process and low cost.

  1. Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Scolari, Lara; Weirich, Johannes

    2008-01-01

    A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at X=1364nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed...

  2. Quantum state propagation in linear photonic bandgap structures

    Czech Academy of Sciences Publication Activity Database

    Severini, S.; Tricca, S.; Sibilia, C.; Peřina, Jan

    2004-01-01

    Roč. 6, - (2004), s. 110-114 ISSN 1464-4266 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010921 Keywords : photonic crystals * coupled mode theory * decoherence * quantum states propagation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.746, year: 2004

  3. THz Photonic Band-Gap Prisms Fabricated by Fiber Drawing

    DEFF Research Database (Denmark)

    Busch, Stefan F.; Xu, Lipeng; Stecher, Matthias

    2012-01-01

    We suggest a novel form of polymeric based 3D photonic crystal prisms for THz frequencies which could be fabricated using a standard fiber drawing technique. The structures are modeled and designed using a finite element analyzing technique. Using this simulation software we theoretically study...

  4. Liquid crystal parameter analysis for tunable photonic bandgap fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei

    2010-01-01

    We investigate the tunability of splay-aligned liquid crystals for the use in solid core photonic crystal fibers. Finite element simulations are used to obtain the alignment of the liquid crystals subject to an external electric field. By means of the liquid crystal director field the optical...

  5. A 98 W 1178 nm Yb-doped solid-core photonic bandgap fiber oscillator

    International Nuclear Information System (INIS)

    Fan, Xinyan; Chen, Mingchen; Shirakawa, Akira; Ueda, Ken-ichi; Olausson, Christina B; Broeng, Jes

    2013-01-01

    A high-power ytterbium-doped solid-core photonic bandgap fiber laser directly oscillating at 1178 nm is reported. The sharp-cut bandpass distributed filtering effect of photonic bandgap fiber can suppress amplified spontaneous emission (ASE) in the conventional high-gain spectral region. The oscillator is composed of a high reflection fiber Bragg grating spliced with a 39 m gain fiber and a Fresnel fiber end surface. A model based on rate equations is investigated numerically. A record output power of 98 W is achieved with a slope efficiency of 54%. The laser linewidth is 0.5 nm. The spectrum at 98 W indicates that ASE and parasitic lasing are suppressed effectively. (letter)

  6. Hyperuniform Disordered photonic bandgap materials, from 2D to 3D, and their applications

    Science.gov (United States)

    Man, Weining; Florescu, Marian; Sahba, Shervin; Sellers, Steven

    Recently, hyperuniform disordered systems attracted increasing attention due to their unique physical properties and the potential possibilities of self-assembling them. We had introduced a class of 2D hyperuniform disordered (HUD) photonic bandgap (PBG) materials enabled by a novel constrained optimization method for engineering the material's isotropic photonic bandgap. The intrinsic isotropy in these disordered structures is an inherent advantage associated with the lack of crystalline order, offering unprecedented freedom for functional defect design impossible to achieve in photonic crystals. Beyond our previous experimental work using macroscopic samples with microwave radiation, we demonstrated functional devices based on submicron-scale planar hyperuniform disordered PBG structures further highlight their ability to serve as highly compact, flexible and energy-efficient platforms for photonic integrated circuits. We further extended the design, fabrication, and characterization of the disordered photonic system into 3D. We also identify local self-uniformity as a novel measure of a disordered network's internal structural similarity, which we found crucial for photonic band gap formation. National Science Foundations award DMR-1308084.

  7. Theory of adiabatic pressure-gradient soliton compression in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Roberts, John

    2009-01-01

    Adiabatic soliton compression by means of a pressure gradient in a hollow-core photonic bandgap fiber is investigated theoretically and numerically. It is shown that the dureation of the compressed pulse is limited mainly by the interplay between third-order dispersion and the Raman-induced soliton...... frequency shift. Analytical expressions for this limit are derived and compared with results of detailed numerical simulations for a realistic fiber structure....

  8. Creation of tunable absolute bandgaps in a two-dimensional anisotropic photonic crystal modulated by a nematic liquid crystal

    International Nuclear Information System (INIS)

    Liu Chenyang

    2008-01-01

    Photonic crystals (PCs) have many potential applications because of their ability to control light-wave propagation. We have investigated the tunable absolute bandgap in a two-dimensional anisotropic photonic crystal structures modulated by a nematic liquid crystal. The PC structure composed of an anisotropic-dielectric cylinder in the liquid crystal medium is studied by solving Maxwell's equations using the plane wave expansion method. The photonic band structures are found to exhibit absolute bandgaps for the square and triangular lattices. Numerical simulations show that the absolute bandgaps can be continuously tuned in the square and triangular lattices consisting of anisotropic-dielectric cylinders by infiltrating nematic liquid crystals. Such a mechanism of bandgap adjustment should open up a new application for designing components in photonic integrated circuits

  9. Nonlinear Bloch waves in metallic photonic band-gap filaments

    International Nuclear Information System (INIS)

    Kaso, Artan; John, Sajeev

    2007-01-01

    We demonstrate the occurrence of nonlinear Bloch waves in metallic photonic crystals (PCs). These periodically structured filaments are characterized by an isolated optical pass band below an effective plasma gap. The pass band occurs in a frequency range where the metallic filament exhibits a negative, frequency-dependent dielectric function and absorption loss. The metallic losses are counterbalanced by gain in two models of inhomogeneously broadened nonlinear oscillators. In the first model, we consider close-packed quantum dots that fill the void regions of a two-dimensional (2D) metallic PC, and whose inhomogeneously broadened emission spectrum spans the original optical pass band of the bare filament. In the second model, we consider thin (10-50 nm) layers of inhomogeneously broadened two-level resonators, with large dipole oscillator strength, that cover the interior surfaces of 2D metallic (silver and tungsten) PCs. These may arise from localized surface plasmon resonances due to small metal particles or an otherwise rough metal surface. For simplicity, we treat electromagnetic modes with electric field perpendicular to the plane of metal periodicity. In both models, a pumping threshold of the resonators is found, above which periodic nonlinear solutions of Maxwell's equations with purely real frequency within the optical pass band emerge. These nonlinear Bloch waves exhibit a laserlike input pumping to output amplitude characteristic. For strong surface resonances, these nonlinear waves may play a role in light emission from a hot tungsten (suitably microstructured) filament

  10. Nonlinear Bloch waves in metallic photonic band-gap filaments

    Science.gov (United States)

    Kaso, Artan; John, Sajeev

    2007-11-01

    We demonstrate the occurrence of nonlinear Bloch waves in metallic photonic crystals (PCs). These periodically structured filaments are characterized by an isolated optical pass band below an effective plasma gap. The pass band occurs in a frequency range where the metallic filament exhibits a negative, frequency-dependent dielectric function and absorption loss. The metallic losses are counterbalanced by gain in two models of inhomogeneously broadened nonlinear oscillators. In the first model, we consider close-packed quantum dots that fill the void regions of a two-dimensional (2D) metallic PC, and whose inhomogeneously broadened emission spectrum spans the original optical pass band of the bare filament. In the second model, we consider thin (10 50 nm) layers of inhomogeneously broadened two-level resonators, with large dipole oscillator strength, that cover the interior surfaces of 2D metallic (silver and tungsten) PCs. These may arise from localized surface plasmon resonances due to small metal particles or an otherwise rough metal surface. For simplicity, we treat electromagnetic modes with electric field perpendicular to the plane of metal periodicity. In both models, a pumping threshold of the resonators is found, above which periodic nonlinear solutions of Maxwell’s equations with purely real frequency within the optical pass band emerge. These nonlinear Bloch waves exhibit a laserlike input pumping to output amplitude characteristic. For strong surface resonances, these nonlinear waves may play a role in light emission from a hot tungsten (suitably microstructured) filament.

  11. Broadband optically controlled switching effect in a microfluid-filled photonic bandgap fiber

    International Nuclear Information System (INIS)

    Guo, Junqi; Liu, Yan-ge; Wang, Zhi; Luo, Mingming; Huang, Wei; Liu, Xiaoqi; Han, Tingting

    2016-01-01

    Broadband optically controlled switching in a microfluid-filled photonic bandgap fiber (MF-PBGF) was observed and investigated. The MF-PBGF was formed by infusing a temperature-sensitive high-index fluid into all of the cladding holes of a microstructured optical fiber (MOF). The fiber was then side pumped with a 532 nm continuous wave laser. An extinction ratio of greater than 20 dB at most of the bandgap wavelengths (more than 200 nm) was obtained with a switching power of ∼147 mW. Theoretical and experimental investigations revealed that the effect originated from changes in the temperature gradient induced by heat absorption of the fiber coating with laser illumination. These investigations offer a new and simple approach to achieve wideband and flexible all-optical fiber switching devices without using any photosensitive materials. (paper)

  12. Mode division multiplexing over 19-cell hollow-core photonic bandgap fibre by employing integrated mode multiplexer

    NARCIS (Netherlands)

    Chen, H.; Uden, van R.G.H.; Okonkwo, C.M.; Jung, Y.; Wheeler, N.V.; Fokoua, E.N.; Baddela, N.; Petrovich, M.N.; Poletti, F.; Richardson, D.J.; Raz, O.; Waardt, de H.; Koonen, A.M.J.

    2014-01-01

    A photonic integrated mode coupler based on silicon-on-insulator is employed for mode division multiplexing (MDM) over a 193 m 19-cell hollow-core photonic bandgap fibre (HC-PBGF) with a -3 dB bandwidth >120 nm. Robust MDM transmissions using LP01 and LP11 modes, and two degenerate LP11 modes (LP11a

  13. Microstructured and Photonic Bandgap Fibers for Applications in the Resonant Bio- and Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Maksim Skorobogatiy

    2009-01-01

    Full Text Available We review application of microstructured and photonic bandgap fibers for designing resonant optical sensors of changes in the value of analyte refractive index. This research subject has recently invoked much attention due to development of novel fiber types, as well as due to development of techniques for the activation of fiber microstructure with functional materials. Particularly, we consider two sensors types. The first sensor type employs hollow core photonic bandgap fibers where core guided mode is confined in the analyte filled core through resonant effect in the surrounding periodic reflector. The second sensor type employs metalized microstructured or photonic bandgap waveguides and fibers, where core guided mode is phase matched with a plasmon propagating at the fiber/analyte interface. In resonant sensors one typically employs fibers with strongly nonuniform spectral transmission characteristics that are sensitive to changes in the real part of the analyte refractive index. Moreover, if narrow absorption lines are present in the analyte transmission spectrum, due to Kramers-Kronig relation this will also result in strong variation in the real part of the refractive index in the vicinity of an absorption line. Therefore, resonant sensors allow detection of minute changes both in the real part of the analyte refractive index (10−6–10−4 RIU, as well as in the imaginary part of the analyte refractive index in the vicinity of absorption lines. In the following we detail various resonant sensor implementations, modes of operation, as well as analysis of sensitivities for some of the common transduction mechanisms for bio- and chemical sensing applications. Sensor designs considered in this review span spectral operation regions from the visible to terahertz.

  14. Influence of air pressure on soliton formation in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Roberts, Peter John

    2009-01-01

    Abstract Soliton formation during dispersive compression of chirped few-picosecond pulses at the microjoule level in a hollow-core photonic bandgap (HC-PBG) fiber is studied by numerical simulations. Long-pass filtering of the emerging frequency-shifted solitons is investigated with the objective...... of obtaining pedestal-free output pulses. Particular emphasis is placed on the influence of the air pressure in the HC-PBG fiber. It is found that a reduction in air pressure enables an increase in the fraction of power going into the most redshifted soliton and also improves the quality of the filtered pulse...

  15. High-directivity planar antenna using controllable photonic bandgap material at microwave frequencies

    International Nuclear Information System (INIS)

    de Lustrac, A.; Gadot, F.; Akmansoy, E.; Brillat, T.

    2001-01-01

    In this letter, we experimentally demonstrate the capability of a controllable photonic bandgap (CPBG) material to conform the emitted radiation of a planar antenna at 12 GHz. The CPBG material is a variable conductance lattice fabricated with high-frequency PIN diodes soldered along metallic stripes on dielectric printed boards. Depending on the diode bias, the emitted radiation of the antenna can be either transmitted or totally reflected by the material. In the transmission state, the antenna radiation is spatially filtered by the CPBG material in a sharp beam perpendicular to the surface of the material. [copyright] 2001 American Institute of Physics

  16. Analysis of photonic band-gap (PBG) structures using the FDTD method

    DEFF Research Database (Denmark)

    Tong, M.S.; Cheng, M.; Lu, Y.L.

    2004-01-01

    In this paper, a number of photonic band-gap (PBG) structures, which are formed by periodic circuit elements printed oil transmission-line circuits, are studied by using a well-known numerical method, the finite-difference time-domain (FDTD) method. The results validate the band-stop filter...... behavior of these structures, and the computed results generally match well with ones published in the literature. It is also found that the FDTD method is a robust, versatile, and powerful numerical technique to perform such numerical studies. The proposed PBG filter structures may be applied in microwave...

  17. Noise filtering in a multi-channel system using a tunable liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Scolari, Lara; Tokle, Torger

    2008-01-01

    This paper reports on the first application of a liquid crystal infiltrated photonic bandgap fiber used as a tunable filter in an optical transmission system. The device allows low-cost amplified spontaneous emission (ASE) noise filtering and gain equalization with low insertion loss and broad...... tunability. System experiments show that the use of this filter increases for times the distance over which the optical signal-to-noise ratio (OSNR) is sufficient for error-free transmission with respect to the case in which no filtering is used....

  18. Bandgap characteristics of 2D plasma photonic crystal with oblique incidence: TM case

    International Nuclear Information System (INIS)

    Xie Ying-Tao; Yang Li-Xia

    2011-01-01

    A novel periodic boundary condition (PBC), that is the constant transverse wavenumber (CTW) method, is introduced to solve the time delay in the transverse plane with oblique incidence. Based on the novel PBC, the FDTD/PBC algorithm is proposed to study periodic structure consisting of plasma and vacuum. Then the reflection coefficient for the plasma slab from the FDTD/PBC algorithm is compared with the analytic results to show the validity of our technique. Finally, the reflection coefficients for the plasma photonic crystals are calculated using the FDTD/PBC algorithm to study the variation of bandgap characteristics with the incident angle and the plasma parameters. Thus it has provided the guiding sense for the actual manufacturing plasma photonic crystal. (general)

  19. High-Power Yb-Doped Solid-Core Photonic Bandgap Fiber Amplifier at 1150-1200nm

    DEFF Research Database (Denmark)

    Maruyama, H.; Shirakawa, A.; Ueda, K.

    2008-01-01

    Solid-core photonic-bandgap fiber amplification at the long-wavelength edge of ytterbium band is reported. A 32W output at 1156nm with a 66% slope efficiency and 9.1W output at 1178nm were succesfully obtained.......Solid-core photonic-bandgap fiber amplification at the long-wavelength edge of ytterbium band is reported. A 32W output at 1156nm with a 66% slope efficiency and 9.1W output at 1178nm were succesfully obtained....

  20. Compression of realistic laser pulses in hollow-core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Roberts, John

    2009-01-01

    Dispersive compression of chirped few-picosecond pulses at the microjoule level in a hollow-core photonic bandgap fiber is studied numerically. The performance of ideal parabolic input pulses is compared to pulses from a narrowband picosecond oscillator broadened by self-phase modulation during...... amplification. It is shown that the parabolic pulses are superior for compression of high-quality femtosecond pulses up to the few-megawatts level. With peak powers of 5-10 MW or higher, there is no significant difference in power scaling and pulse quality between the two pulse types for comparable values...... of power, duration, and bandwidth. The same conclusion is found for the peak power and energy of solitons formed beyond the point of maximal compression. Long-pass filtering of these solitons is shown to be a promising route to clean solitonlike output pulses with peak powers of several MW....

  1. Gamma irradiation of minimal latency Hollow-Core Photonic Bandgap Fibres

    CERN Document Server

    Olanterae, L; Richardson, D J; Vasey, F; Wooler, J P; Petrovich, M N; Wheeler, N V; Poletti, F; Troska, J

    2013-01-01

    Hollow-Core Photonic-Bandgap Fibres (HC-PBGFs) offer several distinct advantages over conventional fibres, such as low latency and radiation hardness; properties that make HC-PBGFs interesting for the high energy physics community. This contribution presents the results from a gamma irradiation test carried out using a new type of HC-PBGF that combines sufficiently low attenuation over distances that are compatible with high energy physics applications together with a transmission bandwidth that covers the 1550 nm region. The radiation induced attenuation of the HC-PBGF was two orders of magnitude lower than that of a conventional fibre during a 67.5 h exposure to gamma-rays, resulting in a radiation-induced attenuation of only 2.1 dB/km at an accumulated dose of 940 kGy.

  2. Effect of single point defects on the confinement losses of air-guiding photonic bandgap fibers

    Institute of Scientific and Technical Information of China (English)

    Shi Wei-Hua; Zhao Yan; Qian Li-Guo; Chen He-Ming

    2012-01-01

    The confinement losses in air-guiding photonic bandgap fibers (PBGFs) with air hole missing are studied with the full-vector finite-element method.It is confirmed that there are two loss peaks (1.555 and 1.598 μm) if there is a hole missing in the cladding far from the core.The closer to the core the hole missing is,the larger the confinement losses are,and even no mode could propagate in the core.The main power of the fundamental mode leaks from the core to the cladding defect.The quality of PBGFs can be improved through controlling the number and position of defects.

  3. Experimental investigation of backreflection at air-core photonic bandgap fiber terminations

    Science.gov (United States)

    Xu, Xiaobin; Yan, Ming; Wu, Chunxiao; Song, Ningfang; Zhang, Chunxi

    2017-07-01

    Backreflection from the termination of air-core photonic bandgap fibers (PBFs) is experimentally investigated based on a range-extended Mach-Zehnder and Michelson hybrid (M2) interferometer. For primary waves generated by the fundamental modes, the reflectivity is about -90 dB; for secondary waves caused by other modes, the reflectivity is less than -80 dB when compared to the intensity of the primary wave and -20 to -50 dB when compared to their own incident intensity. To suppress the reflection, 3-centimeter PBF at the end is filled with alcohol through the capillary effect, and this proposed method is shown to be much more convenient and effective than the conventional angle cleaving method.

  4. Continuously tunable devices based on electrical control of dual-frequency liquid crystal filled photonic bandgap fibers

    DEFF Research Database (Denmark)

    Scolari, Lara; Alkeskjold, Thomas Tanggaard; Riishede, Jesper

    2005-01-01

    We present an electrically controlled photonic bandgap fiber device obtained by infiltrating the air holes of a photonic crystal fiber (PCF) with a dual-frequency liquid crystal (LC) with pre-tilted molecules. Compared to previously demonstrated devices of this kind, the main new feature of this ...... in the same device. We investigate the dynamics of this device and demonstrate a birefringence controller based on this principle....

  5. Fabrication of a three-dimensional photonic band-gap crystal of air-spheres in a titania matrix

    Science.gov (United States)

    Diop, M.; Maurin, G.; Tork, Amir; Lessard, Roger A.

    2003-02-01

    A three-dimensional (3D) colloidal crystal have been grown from an aqueous colloidal solution of highly monodisperse submicrometer-sized polystyrene spheres using a self-assembly processing technique. The electromagnetic waves diffracted by this crystal can interfere and give rise to a photonic band-gap. However, due to the low refractive index contrast within this material the band-gap is incomplete. By filling the voids between the spheres of the colloidal crystal with titania and removing the polystyrene beads by sublimation, we obtained an inverse-opal structure with an increased refractive index contrast showing strong opalescence.

  6. Resonance interaction energy between two entangled atoms in a photonic bandgap environment.

    Science.gov (United States)

    Notararigo, Valentina; Passante, Roberto; Rizzuto, Lucia

    2018-03-26

    We consider the resonance interaction energy between two identical entangled atoms, where one is in the excited state and the other in the ground state. They interact with the quantum electromagnetic field in the vacuum state and are placed in a photonic-bandgap environment with a dispersion relation quadratic near the gap edge and linear for low frequencies, while the atomic transition frequency is assumed to be inside the photonic gap and near its lower edge. This problem is strictly related to the coherent resonant energy transfer between atoms in external environments. The analysis involves both an isotropic three-dimensional model and the one-dimensional case. The resonance interaction asymptotically decays faster with distance compared to the free-space case, specifically as 1/r 2 compared to the 1/r free-space dependence in the three-dimensional case, and as 1/r compared to the oscillatory dependence in free space for the one-dimensional case. Nonetheless, the interaction energy remains significant and much stronger than dispersion interactions between atoms. On the other hand, spontaneous emission is strongly suppressed by the environment and the correlated state is thus preserved by the spontaneous-decay decoherence effects. We conclude that our configuration is suitable for observing the elusive quantum resonance interaction between entangled atoms.

  7. Sub-bandgap photonic base current method for characterization of interface states at heterointerfaces in heterojunction bipolar transistors

    International Nuclear Information System (INIS)

    Shin, H. T.; Kim, K. H.; Kim, K. S.

    2004-01-01

    In this paper, we propose a novel photonic base current analysis method to characterize the interface states in heterojunction bipolar transistors (HBTs) by using the photonic I-V characteristics under sub-bandgap photonic excitation. For the photonic current-voltage characterization of HBTs, an optical source with a photon energy less than the bandgap energy of Al 0.3 Ga 0.7 As and GaAs (E ph = 0.95 eV g,AlGaAs = 1.79 eV, E g,GaAs = 1.45 eV) is employed for the characterization of the interface states distributed in the photo-responsive energy band (E C - 0.95 ≤ E it ≤ E C ) in emitter-base heterojunction at HBTs. The proposed novel method, which is applied to bipolar junction transistors for the first time, is simple, and an accurate analysis of interface traps in HBTs is possible. By using the photonic base-current and the dark-base-current, we qualitatively analyze the interface trap at the Al 0.3 Ga 0.7 As/GaAs heterojunction interface in HBTs.

  8. Reduced thermal sensitivity of hybrid air-core photonic band-gap fiber ring resonator

    Science.gov (United States)

    Feng, Li-shuang; Wang, Kai; Jiao, Hong-chen; Wang, Jun-jie; Liu, Dan-ni; Yang, Zhao-hua

    2018-01-01

    A novel hybrid air-core photonic band-gap fiber (PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coefficient of air-core PBF and Panda fiber. Experimental results show that the relative temperature dependent birefringence coefficient of air-core PBF is 1.42×10-8/°C, which is typically 16 times less than that of Panda fiber. Then, we extract the geometry profile of air-core PBF from scanning electron microscope (SEM) images. Numerical modal is built to distinguish the fast axis and slow axis in the fiber. By precisely setting the length difference in air-core PBF and Panda fiber between two 90° polarization-axis rotated splicing points, the hybrid air-core PBF ring resonator is constructed, and the finesse of the resonator is 8.4. Environmental birefringence variation induced by temperature change can be well compensated, and experimental results show an 18-fold reduction in thermal sensitivity, compared with resonator with twin 0° polarization-axis rotated splices.

  9. Bandgap optimization of two-dimensional photonic crystals using semidefinite programming and subspace methods

    International Nuclear Information System (INIS)

    Men, H.; Nguyen, N.C.; Freund, R.M.; Parrilo, P.A.; Peraire, J.

    2010-01-01

    In this paper, we consider the optimal design of photonic crystal structures for two-dimensional square lattices. The mathematical formulation of the bandgap optimization problem leads to an infinite-dimensional Hermitian eigenvalue optimization problem parametrized by the dielectric material and the wave vector. To make the problem tractable, the original eigenvalue problem is discretized using the finite element method into a series of finite-dimensional eigenvalue problems for multiple values of the wave vector parameter. The resulting optimization problem is large-scale and non-convex, with low regularity and non-differentiable objective. By restricting to appropriate eigenspaces, we reduce the large-scale non-convex optimization problem via reparametrization to a sequence of small-scale convex semidefinite programs (SDPs) for which modern SDP solvers can be efficiently applied. Numerical results are presented for both transverse magnetic (TM) and transverse electric (TE) polarizations at several frequency bands. The optimized structures exhibit patterns which go far beyond typical physical intuition on periodic media design.

  10. A 158 fs 5.3 nJ fiber-laser system at 1 mu m using photonic bandgap fibers for dispersion control and pulse compression

    DEFF Research Database (Denmark)

    Nielsen, C.K.; Jespersen, Kim Giessmann; Keiding, S.R.

    2006-01-01

    We demonstrate a 158 fs 5.3 nJ mode-locked laser system based on a fiber oscillator, fiber amplifier and fiber compressor. Dispersion compensation in the fiber oscillator was obtained with a solid-core photonic bandgap (SC-PBG) fiber spliced to standard fibers, and external compression is obtained...... with a hollow-core photonic bandgap (HC-PBG) fiber....

  11. Compact Design of an Electrically Tunable and Rotatable Polarizer Based on a Liquid Crystal Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    In this letter, a compact electrically controlled broadband liquid crystal (LC) photonic bandgap fiber polarizer is designed and fabricated. A good fiber coupling quality between two single-mode fibers and one 10-mm-long LC-filled photonic crystal fiber is obtained and protected by using SU-8 fiber...... fixing structures during the device assembly. The total insertion loss of this all-in-fiber device is 2.7 dB. An electrically tunable polarization extinction ratio of 21.3 dB is achieved with 45$^{circ}$ rotatable transmission axis as well as switched on and off in the wavelength range of 1300–1600 nm....

  12. Enhanced Cerenkov second-harmonic generation in a planar nonlinear waveguide that reproduces a one-dimensional photonic bandgap structure

    International Nuclear Information System (INIS)

    Pezzetta, D.; Sibilia, C.; Bertolotti, M.; Ramponi, R.; Osellame, R.; Marangoni, M.; Haus, J. W.; Scalora, M.; Bloemer, M. J.; Bowden, C. M.

    2002-01-01

    Second-harmonic generation in the Cerenkov configuration is investigated under conditions for which the use of a linear grating fabricated on top of the waveguide reproduces a photonic bandgap structure. The fundamental mode of the guide at the fundamental frequency is tuned at the photonic band-edge resonance, thus producing great confinement and enhancement of the electromagnetic field inside the structure. The conversion efficiency achieved in both the forward and the backward directions is at least 1 order of magnitude greater than that of a conventional Cerenkov emission in a waveguide of the same length. An analysis of the tolerances of the grating period on the conversion efficiency is presented

  13. Bandgap Engineering of Double Perovskites for One- and Two-photon Water Splitting

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2013-01-01

    Computational screening is becoming increasingly useful in the search for new materials. We are interested in the design of new semiconductors to be used for light harvesting in a photoelectrochemical cell. In the present paper, we study the double perovskite structures obtained by combining 46...... stable cubic perovskites which was found to have a finite bandgap in a previous screening-study. The four-metal double perovskite space is too large to be investigated completely. For this reason we propose a method for combining different metals to obtain a desired bandgap. We derive some bandgap design...... rules on how to combine two cubic perovskites to generate a new combination with a larger or smaller bandgap compared with the constituent structures. Those rules are based on the type of orbitals involved in the conduction bands and on the size of the two cubic bandgaps. We also see that a change...

  14. High power breakdown testing of a photonic band-gap accelerator structure with elliptical rods

    Directory of Open Access Journals (Sweden)

    Brian J. Munroe

    2013-01-01

    Full Text Available An improved single-cell photonic band-gap (PBG structure with an inner row of elliptical rods (PBG-E was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz, achieving a gradient of 128  MV/m at a breakdown probability of 3.6×10^{-3} per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications.

  15. LETTER TO THE EDITOR: Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis

    Science.gov (United States)

    Ullrich, B.; Schroeder, R.

    2001-08-01

    Thin (10 µm) film CdS on Pyrex® formed by spray pyrolysis is excited below the gap at 804 nm with 200 fs laser pulses at room temperature. Excitation intensities up to 250 GW cm-2 evoke green bandgap emission due to two-photon transitions. This two-photon photoluminescence does not show a red emission contribution in contrast to the single-photon excited emission, which is dominated by broad emission in the red spectral range. It is demonstrated that two-photon excitation causes photo-induced bandgap narrowing due to Debye screening. At 250 GW cm-2 bandgap narrowing of 47 meV is observed, which corresponds to an excited electron density of 1.6×1018 cm-3.

  16. All-silica photonic bandgap fibre with zero dispersion and a large mode area at 730 nm

    DEFF Research Database (Denmark)

    Riishede, Jesper; Lægsgaard, Jesper; Broeng, Jes

    2004-01-01

    A theoretical analysis of a photonic bandgap fibre, consisting of a pure silica background with a triangular lattice of Ge-doped high-index rods, is presented. This novel fibre design guides a single, well-confined mode in a core region made from undoped silica. The fibre is found to have positive...... waveguide dispersion, which may be used to shift the zero-dispersion wavelength down to 730 nm, while maintaining an effective mode area of 17 $mu@-m$+2$/. This is an order of magnitude larger than what may be achieved in highly non-linear index-guiding microstructured fibres with comparable zero...

  17. Single-mode ytterbium-doped large-mode-area photonic bandgap rod fiber amplifier

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Broeng, Jes

    2011-01-01

    bandgap structure. The structure allows resonant coupling of higher-order modes from the core and acts as a spatially Distributed Mode Filter (DMF). With this approach, we demonstrate passive SM performance in an only ~50cm long and straight ytterbium-doped rod fiber. The amplifier has a mode field...... diameter of ∼59Lim at 1064nm and exhibits a pump absorption of 27dB/m at 976nm. © 2011 Optical Society of America....

  18. Enhanced complete photonic bandgap in a moderate refractive index contrast chalcogenide-air system with connected-annular-rods photonic crystals

    KAUST Repository

    Hou, Jin

    2018-03-27

    Connected-annular-rods photonic crystals (CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap (CPBG) for chalcogenide material systems with moderate refractive index contrast. For the typical chalcogenide-glass–air system with an index contrast of 2.8:1, the optimized square lattice CARPC exhibits a significantly larger normalized CPBG of about 13.50%, though the use of triangular lattice CARPC is unable to enhance the CPBG. It is almost twice as large as our previously reported result [IEEE J. Sel. Top. Quantum Electron. 22, 4900108 (2016) [CrossRef] ]. Moreover, the CPBG of the square-lattice CARPC could remain until an index contrast as low as 2.24:1. The result not only favors wideband CPBG applications for index contrast systems near 2.8:1, but also makes various optical applications that are dependent on CPBG possible for more widely refractive index contrast systems.

  19. Hypersonic modulation of light in three-dimensional photonic and phononic band-gap materials.

    Science.gov (United States)

    Akimov, A V; Tanaka, Y; Pevtsov, A B; Kaplan, S F; Golubev, V G; Tamura, S; Yakovlev, D R; Bayer, M

    2008-07-18

    The elastic coupling between the a-SiO2 spheres composing opal films brings forth three-dimensional periodic structures which besides a photonic stop band are predicted to also exhibit complete phononic band gaps. The influence of elastic crystal vibrations on the photonic band structure has been studied by injection of coherent hypersonic wave packets generated in a metal transducer by subpicosecond laser pulses. These studies show that light with energies close to the photonic band gap can be efficiently modulated by hypersonic waves.

  20. In vivo imaging of the morphology and changes in pH along the gastrointestinal tract of Japanese medaka by photonic band-gap hydrogel microspheres

    International Nuclear Information System (INIS)

    Du, Xuemin; Lei, Ngai-Yu; Hu, Peng; Lei, Zhang; Ong, Daniel Hock-Chun; Ge, Xuewu; Zhang, Zhicheng; Lam, Michael Hon-Wah

    2013-01-01

    Graphical abstract: -- Highlights: •Fabrication of pH-responsive photonic colloidal crystalline microspheres. •Specific photonic band-gap responses occurred in the pH range of 4–5. •Remarkably low in vivo toxicity to Japanese medaka (Oryzia latipes). •In vivo imaging of the morphology and pH along GI tract of Japanese medaka. •Demonstrates bio-imaging potentials of stimuli-responsive photonic materials. -- Abstract: Colloidal crystalline microspheres with photonic band-gap properties responsive to media pH have been developed for in vivo imaging purposes. These colloidal crystalline microspheres were constructed from monodispersed core–shell nano-size particles with poly(styrene-co-acrylic acid) (PS-co-PAA) cores and poly(acrylic acid-co-N-isopropylacrylamide) (PAA-co-PNIPAM) hydrogel shells cross-linked by N,N′-methylenebisacrylamide. A significant shift in the photonic band-gap properties of these colloidal crystalline microspheres was observed in the pH range of 4–5. This was caused by the discontinuous volume phase transition of the hydrogel coating, due to the protonation/deprotonation of its acrylic acid moieties, on the core–shell nano-sized particles within the microspheres. The in vivo imaging capability of these pH-responsive photonic microspheres was demonstrated on a test organism – Japanese medaka, Oryzia latipes – in which the morphology and change in pH along their gastrointestinal (GI) tracts were revealed under an ordinary optical microscope. This work illustrates the potential of stimuli-responsive photonic band-gap materials in tissue-/organ-level in vivo bio-imaging

  1. Wave Propagation in Linear and Nonlinear Photonic Band-Gap Materials

    National Research Council Canada - National Science Library

    Venakides, Stephanos

    2003-01-01

    .... Development of 3D boundary element code for EM scattering off photonic crystal slabs. Development of 2D FDTD code that includes nonlinearities and use in studying resonant phenomena. Nonlinear Effects...

  2. A versatile optical junction using photonic band-gap guidance and self collimation

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Man Mohan; Medhekar, Sarang, E-mail: smedhekarbit@gmail.com [Centre for Applied Physics, Central University of Jharkhand, Ranchi 835205 (India)

    2014-09-29

    We show that it is possible to design two photonic crystal (PC) structures such that an optical beam of desired wavelength gets guided within the line defect of the first structure (photonic band gap guidance) and the same beam gets guided in the second structure by self-collimation. Using two dimensional simulation of a design made of the combination of these two structures, we propose an optical junction that allows for crossing of two optical signals of same wavelength and same polarization with very low crosstalk. Moreover, the junction can be operated at number of frequencies in a wide range. Crossing of multiple beams with very low cross talk is also possible. The proposed junction should be important in future integrated photonic circuits.

  3. Nonlinear optical sub-bandgap excitation of ZnO-based photonic resonators

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Christina A.; Zeuner, Franziska; Bader, Manuel H. W.; Zentgraf, Thomas; Meier, Cedrik [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Universität Paderborn, Warburger Str. 100, 33098 Paderborn (Germany)

    2015-12-07

    Zinc oxide (ZnO) is a versatile candidate for photonic devices due to its highly efficient optical emission. However, for pumping of ZnO photonic devices UV-sources are required. Here, we investigate the alternative usage of widely available pulsed near-infrared (NIR)-sources and compare the efficiency of linear and nonlinear excitation processes. We found that bulk ZnO, ZnO thin films grown by molecular beam epitaxy, and ZnO/SiO{sub 2} microdisk devices exhibit strong nonlinear response when excited with NIR pulses (λ ≈ 1060 nm). In addition, we show that the ZnO/SiO{sub 2} microdisks exhibit sharp whispering gallery modes over the blue-yellow part of the visible spectrum for both excitation conditions and high Q-factors up to Q = 4700. The results demonstrate that nonlinear excitation is an efficient way to pump ZnO photonic devices.

  4. Photonic Crystals with Large Complete Bandgap Composed of an Approximately Ordered Array of Laurel-Crown-Like Structures Fabricated by Employing Anodic Aluminum Oxide Template

    Science.gov (United States)

    Chan, Der-Sheng; Chau, Yuan-Fong

    2013-01-01

    An innovative fabrication processes of a photonic crystal composed of an approximately ordered array of laurel-crown-like structures by employing an anodic aluminum oxide (AAO) template is presented. We found that the intensity of the electric field is affected by the microstructure and surface morphology of aluminum foil after etching the scalloped barrier oxide layer (BOL). In addition, the electric current is strongly dependent on the electric field distribution in the scalloped BOL at the pore bottoms. By using a different step potential (DSP) of 30-60 V in series, the proposed photonic crystal is fabricated and possesses a large complete photonic bandgap.

  5. Monolithic Yb-fiber femtosecond laser with intracavity all-solid PBG fiber and ex-cavity HC-PCF

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Liu, Xiaomin; Lægsgaard, Jesper

    2010-01-01

    (PM) photonic bandgap fiber (PBG) is used in the cavity of the master oscillator for dispersion compensation and stabilization of modelocking. The final compression of an chirped-pulse-amplified laser signal is performed in a hollow PM PCF, yielding final fiber-delivered pulse energy of around 7 n......J, and pulse duration of around 297 fs. The self-stabilization mechanism of the oscillator, based on the optical nonlinearities in an AS PCF, results in excellent environmental and operational stability of our laser. Stable self-starting fundamental modelocking is maintained for at least 4 days of operation......We demonstrate an all-fiber femtosecond master oscillator / power amplifier operating at the central wavelength of 1033 nm, based on Yb-doped fiber as gain medium, and two different kinds of photonic crystal fibers for dispersion control and stabilization. An all-solid (AS) polarization maintaining...

  6. Investigation on the Effect of Underwater Acoustic Pressure on the Fundamental Mode of Hollow-Core Photonic Bandgap Fibers

    Directory of Open Access Journals (Sweden)

    Adel Abdallah

    2015-01-01

    Full Text Available Recently, microstructured optical fibers have become the subject of extensive research as they can be employed in many civilian and military applications. One of the recent areas of research is to enhance the normalized responsivity (NR to acoustic pressure of the optical fiber hydrophones by replacing the conventional single mode fibers (SMFs with hollow-core photonic bandgap fibers (HC-PBFs. However, this needs further investigation. In order to fully understand the feasibility of using HC-PBFs as acoustic pressure sensors and in underwater communication systems, it is important to study their modal properties in this environment. In this paper, the finite element solver (FES COMSOL Multiphysics is used to study the effect of underwater acoustic pressure on the effective refractive index neff of the fundamental mode and discuss its contribution to NR. Besides, we investigate, for the first time to our knowledge, the effect of underwater acoustic pressure on the effective area Aeff and the numerical aperture (NA of the HC-PBF.

  7. Modeling loss and backscattering in a photonic-bandgap fiber using strong perturbation

    Science.gov (United States)

    Zamani Aghaie, Kiarash; Digonnet, Michel J. F.; Fan, Shanhui

    2013-02-01

    We use coupled-mode theory with strong perturbation to model the loss and backscattering coefficients of a commercial hollow-core fiber (NKT Photonics' HC-1550-02 fiber) induced by the frozen-in longitudinal perturbations of the fiber cross section. Strong perturbation is used, for the first time to the best of our knowledge, because the large difference between the refractive indices of the two fiber materials (silica and air) makes conventional weak-perturbation less accurate. We first study the loss and backscattering using the mathematical description of conventional surface-capillary waves (SCWs). This model implicitly assumes that the mechanical waves on the core wall of a PBF have the same power spectral density (PSD) as the waves that develop on an infinitely thick cylindrical tube with the same diameter as the PBF core. The loss and backscattering coefficients predicted with this thick-wall SCW roughness are 0.5 dB/km and 1.1×10-10 mm-1, respectively. These values are more than one order of magnitude smaller than the measured values (20-30 dB/km and ~1.5×10-9 mm-1, respectively). This result suggests that the thick-wall SCW PSD is not representative of the roughness of our fiber. We found that this discrepancy occurs at least in part because the effect of the finite thickness of the silica membranes (only ~120 nm) is neglected. We present a new expression for the PSD that takes into account this finite thickness and demonstrates that the finite thickness substantially increases the roughness. The predicted loss and backscattering coefficients predicted with this thin-film SCW PSD are 30 dB/km and 1.3×10-9 mm-1, which are both close to the measured values. We also show that the thin-film SCW PSD accurately predicts the roughness PSD measured by others in a solid-core photonic-crystal fiber.

  8. Investigation on bandgap, diffraction, interference, and refraction effects of photonic crystal structure in GaN/InGaN LEDs for light extraction.

    Science.gov (United States)

    Patra, Saroj Kanta; Adhikari, Sonachand; Pal, Suchandan

    2014-06-20

    In this paper, we have made a clear differentiation among bandgap, diffraction, interference, and refraction effects in photonic crystal structures (PhCs). For observing bandgap, diffraction, and refraction effects, PhCs are considered on the top p-GaN surface of light emitting diodes (LEDs), whereas for interference effect, hole type PhCs are considered to be embedded within n-GaN layer of LED. From analysis, it is observed that at a particular lattice periodicity, for which bandgap lies within the wavelength of interest shows a significant light extraction due to inhibition of guided mode. Beyond a certain periodicity, diffraction effect starts dominating and light extraction improves further. The interference effect is observed in embedded photonic crystal LEDs, where depth of etching supports constructive interference of outward light waves. We have also shed light on refraction effects exhibited by the PhCs and whether negative refraction properties of PhCs may be useful in case of LED light extraction.

  9. Microvoid channel polymer photonic crystals with large infrared stop gaps and a multitude of higher-order bandgaps fabricated by femtosecond laser drilling in solid resin

    International Nuclear Information System (INIS)

    Straub, M.; Ventura, M.; Gu, M.

    2004-01-01

    Photosensitive polymer materials are ideally suited for laser-induced micro- and nanostructuring, as structural and compositional changes are achieved already under exposure to moderate intensities of high-repetition rate ultrashort-pulsed light. Photonic crystals with bandgaps in the infrared or the visible spectral region are a particularly interesting application, because highly correlated structural elements at a size of only a few hundred nanometers are required. We fabricated infrared photonic crystals based on microvoid channels inside solid polymer material. Femtosecond-pulsed visible light was focused into UV-cured Norland NOA63 resin by a high numerical aperture objective. In the focal spot microexplosions drive the material out of the center of the focus. Void channels of 0.7-1.3 μm diameter are generated by translating the sample along a preprogrammed pathway. Woodpile structures of void channels at layer spacings of 1.6-2.6 μm and in-plane channel spacings of 1.2-1.3 μm allowed for bandgap-induced suppression of infrared transmission in the stacking direction of as much as 86% by only 20 layers. As these structures are highly correlated and do not contain many imperfections, up to three higher-order stop gaps are observed. Consistent with theory, the number and gapwidth of higher-order gaps strongly increases with the ratio between layer- and in-plane spacing. Due to their low refractive index contrast and the missing interconnectivity of voids our structures do not provide complete photonic bandgaps. However, their manifold of sizable higher-order gaps allows for the engineering of photonic stop gaps down to the near-infrared wavelength region using comparatively large structural dimensions

  10. A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

    Directory of Open Access Journals (Sweden)

    Wagner D.

    2015-01-01

    Full Text Available Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength. A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B, ABmm (MVNA 8-350 and Rohde&Schwarz (ZVA24 together with frequency multipliers. The

  11. Cu2I2Se6: A Metal-Inorganic Framework Wide-Bandgap Semiconductor for Photon Detection at Room Temperature.

    Science.gov (United States)

    Lin, Wenwen; Stoumpos, Constantinos C; Kontsevoi, Oleg Y; Liu, Zhifu; He, Yihui; Das, Sanjib; Xu, Yadong; McCall, Kyle M; Wessels, Bruce W; Kanatzidis, Mercouri G

    2018-02-07

    Cu 2 I 2 Se 6 is a new wide-bandgap semiconductor with high stability and great potential toward hard radiation and photon detection. Cu 2 I 2 Se 6 crystallizes in the rhombohedral R3̅m space group with a density of d = 5.287 g·cm -3 and a wide bandgap E g of 1.95 eV. First-principles electronic band structure calculations at the density functional theory level indicate an indirect bandgap and a low electron effective mass m e * of 0.32. The congruently melting compound was grown in centimeter-size Cu 2 I 2 Se 6 single crystals using a vertical Bridgman method. A high electric resistivity of ∼10 12 Ω·cm is readily achieved, and detectors made of Cu 2 I 2 Se 6 single crystals demonstrate high photosensitivity to Ag Kα X-rays (22.4 keV) and show spectroscopic performance with energy resolutions under 241 Am α-particles (5.5 MeV) radiation. The electron mobility is measured by a time-of-flight technique to be ∼46 cm 2 ·V -1 ·s -1 . This value is comparable to that of one of the leading γ-ray detector materials, TlBr, and is a factor of 30 higher than mobility values obtained for amorphous Se for X-ray detection.

  12. A Wearable All-Solid Photovoltaic Textile.

    Science.gov (United States)

    Zhang, Nannan; Chen, Jun; Huang, Yi; Guo, Wanwan; Yang, Jin; Du, Jun; Fan, Xing; Tao, Changyuan

    2016-01-13

    A solution is developed to power portable electronics in a wearable manner by fabricating an all-solid photovoltaic textile. In a similar way to plants absorbing solar energy for photosynthesis, humans can wear the as-fabricated photovoltaic textile to harness solar energy for powering small electronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. High power all solid state VUV lasers

    International Nuclear Information System (INIS)

    Zhang, Shen-jin; Cui, Da-fu; Zhang, Feng-feng; Xu, Zhi; Wang, Zhi-min; Yang, Feng; Zong, Nan; Tu, Wei; Chen, Ying; Xu, Hong-yan; Xu, Feng-liang; Peng, Qin-jun; Wang, Xiao-yang; Chen, Chuang-tian; Xu, Zu-yan

    2014-01-01

    Highlights: • Polarization and pulse repetition rate adjustable ps 177.3 nm laser was developed. • Wavelength tunable ns, ps and fs VUV lasers were developed. • High power ns 177.3 nm laser with narrow linewidth was investigated. - Abstract: We report the investigation on the high power all solid state vacuum ultra-violet (VUV) lasers by means of nonlinear frequency conversion with KBe 2 BO 3 F 2 (KBBF) nonlinear crystal. Several all solid state VUV lasers have developed in our group, including polarization and pulse repetition rate adjustable picosecond 177.3 nm VUV laser, wavelength tunable nanosecond, picosecond and femtosecond VUV lasers, high power ns 177.3 nm laser with narrow linewidth. The VUV lasers have impact, accurate and precise advantage

  14. Rechargeable sodium all-solid-state battery

    International Nuclear Information System (INIS)

    Zhou, Weidong; Li, Yutao; Xin, Sen; Goodenough, John B.

    2017-01-01

    A reversible plating/stripping of a dendrite-free metallic-sodium anode with a reduced anode/ceramic interfacial resistance is created by a thin interfacial interlayer formed in situ or by the introduction of a dry polymer film. Wetting of the sodium on the interfacial interlayer suppresses dendrite formation and growth at different discharge/charge C-rates. Furthermore, all-solid-state batteries were obtained with a high cycling stability and Coulombic efficiency at 65 °C.

  15. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Liefeng, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Li, Yang [Business and Vocational College of Hainan, Haikou 570203 (China); Li, Ding; Hu, Xiaodong [Research Center for Wide Band Gap Semiconductors, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Li, Hongru, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn [State Key Laboratory for Medicinal Chemistry and Biology, College of Pharmacy, Nankai University, Tianjin 300071 (China)

    2015-04-15

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u} is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.

  16. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    International Nuclear Information System (INIS)

    Feng, Liefeng; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng; Li, Yang; Li, Ding; Hu, Xiaodong; Li, Hongru

    2015-01-01

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I th l and I th u , as shown in Fig. 2; I th l is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I th u is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V j ) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I th l and I th u . The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region

  17. Fabrications of Photonic Bandgap Structures in Si and Ge Substrates Using Laser-Assisted Nanoimprinting of Self-Assembled Nanoparticles

    National Research Council Canada - National Science Library

    Lu, Yongfeng

    2006-01-01

    ...) structures, have attracted the interests of researchers due to the applications in a variety of fields such as optoelectronics, photonics, sensors, photo catalysts, and energy harvesting coatings...

  18. Three-photon excited PL spectroscopy and photo-generated Frenkel defects in wide-bandgap layered CdI2 semiconductors

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2009-01-01

    We performed a three-photon excitation nonlinear photoluminescence (PL) spectroscopy in single crystals of wide-bandgap semiconductors (WBSs). The crystal temperature (T L )-dependent PL emission intensity (I PL ) excited with different excitation power density (P) was measured. The PL emissions showed characteristics I PL with their maxima at around 520 nm. The I PL might be due to the presence of the photo-generated Frenkel defects (FDs) in WBSs. A detailed analysis of the PL spectra showed a third-order power law dependence of the maximum I PL on P for all the crystal temperature T L . The I PL was found to increase with decreasing T L . The results demonstrated the existence of the self-trapped excitons resulting from the presence of the FDs in the crystals.

  19. Three-photon excited PL spectroscopy and photo-generated Frenkel defects in wide-bandgap layered CdI{sub 2} semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.a [Qeensland Micro- and Nanotechnology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Department of Physics, University of Chittagong, Chittagong-4331 (Bangladesh)

    2009-12-14

    We performed a three-photon excitation nonlinear photoluminescence (PL) spectroscopy in single crystals of wide-bandgap semiconductors (WBSs). The crystal temperature (T{sub L})-dependent PL emission intensity (I{sub PL}) excited with different excitation power density (P) was measured. The PL emissions showed characteristics I{sub PL} with their maxima at around 520 nm. The I{sub PL} might be due to the presence of the photo-generated Frenkel defects (FDs) in WBSs. A detailed analysis of the PL spectra showed a third-order power law dependence of the maximum I{sub PL} on P for all the crystal temperature T{sub L}. The I{sub PL} was found to increase with decreasing T{sub L}. The results demonstrated the existence of the self-trapped excitons resulting from the presence of the FDs in the crystals.

  20. Monolithic femtosecond Yb-fiber laser with photonic crystal fibers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    We demonstrate a monolithic stable SESAM-modelocked self-starting Yb-fiber laser. A novel PM all-solid photonic bandgap fiber is used for intra-cavity of dispersion management. The ex-cavity final pulse compression is performed in a spliced-on PM hollow-core photonic crystal fiber. The laser...... directly delivers 9 nJ pulses of 275 fs duration with pulse repetition of 26.7MHz....

  1. Study of the band-gap structure of a 1D-photonic crystal by using different numerical approaches

    International Nuclear Information System (INIS)

    Chen, Jian-Bo; Chen, Yue-Rui; Shen, Yan; Zhou, Wei-Xi; Ren, Jiu-Chun; Zheng, Yu-Xiang; Chen, Liang-Yao

    2010-01-01

    Comparative studies between the transfer matrices method (TMM) and plane wave method (PWM) approaches have been performed on 1D photonics crystal under different conditions to show the differences between these two kinds of calculations. TMM is suitable for the design of 1D photonic crystal device with high precision and is in good agreement with experimental results, but is not suitable for the 2D and 3D photonic structures which are limited by the complicated boundary conditions at micro interfaces. The result based on the PWM approach to deal approximately with the photonic structure in approximation has not yet been strictly verified by experiment, not even for 1D photonic crystal structures. More efforts will be required to explore its validation under all physical conditions to enhance its application.

  2. Direct Bandgap Group IV Materials

    Science.gov (United States)

    2016-01-21

    AFRL-AFOSR-JP-TR-2017-0049 Direct Bandgap group IV Materials Hung Hsiang Cheng NATIONAL TAIWAN UNIVERSITY Final Report 01/21/2016 DISTRIBUTION A...NAME(S) AND ADDRESS(ES) NATIONAL TAIWAN UNIVERSITY 1 ROOSEVELT RD. SEC. 4 TAIPEI CITY, 10617 TW 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING...14. ABSTRACT Direct bandgap group IV materials have been long sought for in both academia and industry for the implementation of photonic devices

  3. Tunable photonic crystals with partial bandgaps from blue phase colloidal crystals and dielectric-doped blue phases.

    Science.gov (United States)

    Stimulak, Mitja; Ravnik, Miha

    2014-09-07

    Blue phase colloidal crystals and dielectric nanoparticle/polymer doped blue phases are demonstrated to combine multiple components with different symmetries in one photonic material, creating a photonic crystal with variable and micro-controllable photonic band structure. In this composite photonic material, one contribution to the band structure is determined by the 3D periodic birefringent orientational profile of the blue phases, whereas the second contribution emerges from the regular array of the colloidal particles or from the dielectric/nanoparticle-doped defect network. Using the planewave expansion method, optical photonic bands of the blue phase I and II colloidal crystals and related nanoparticle/polymer doped blue phases are calculated, and then compared to blue phases with no particles and to face-centred-cubic and body-centred-cubic colloidal crystals in isotropic background. We find opening of local band gaps at particular points of Brillouin zone for blue phase colloidal crystals, where there were none in blue phases without particles or dopants. Particle size and filling fraction of the blue phase defect network are demonstrated as parameters that can directly tune the optical bands and local band gaps. In the blue phase I colloidal crystal with an additionally doped defect network, interestingly, we find an indirect total band gap (with the exception of one point) at the entire edge of SC irreducible zone. Finally, this work demonstrates the role of combining multiple - by symmetry - differently organised components in one photonic crystal material, which offers a novel approach towards tunable soft matter photonic materials.

  4. Interactions of low-power photons with natural opals—PBG materials, photonic control, natural metamaterials, spontaneous laser emissions, and band-gap boundary responses

    International Nuclear Information System (INIS)

    Stem, Michelle R.

    2012-01-01

    Four views of each of the opal research specimens in white light (for in-article or cover), in the same order as the specimens depicted in Fig. 3 of the main manuscript. A.On the left: 1.5 carat oval cabochon precious fire opal. B.In the center: 2.5 carats faceted fancy shield precious fire contra luz with mild adularescence. C.On the right: 5.0 carats round cabochon precious crystal opal with blue adularescence. Highlights: ► Emission of micro-lasers from microspheroid cluster boundary zones (quantum dots). ► Lasers illuminated or fluoresced the intra-opal structures of microspheroid photonic glass clusters. ► Microspheroid boundaries are durable to low power light sources. ► Display of previously unknown low power photonic optic properties. ► The research specimens are natural metamaterials. - Abstract: One overall goal of this research was to examine types of naturally-occurring opals that exhibit photonic control to learn about previously-unknown properties of naturally occurring photonic control that may be developed for broader applications. Three different photon sources were applied consecutively to three different types of natural, flawless, gem-quality precious opals. Two photon sources were lasers (green and red) and one was simulated daylight tungsten white. As each type of precious opal was exposed to each of the photon sources, the respective refractions, reflections, and transmissions were studied. This research is the first to show that applying various pleochroic and laser photon sources to these types of opals revealed significant information regarding naturally occurring photonic control, metamaterials, spontaneous laser emissions, and microspheroid cluster (inter-PBG zone) boundary effects. Plus, minimizing ambient light and the use of low power photon sources were critical to observing the properties regarding this photonic materials research. This research yielded information applicable to the development of materials to advance

  5. Facile construction of dual bandgap optical encoding materials with PS@P(HEMA-co-AA)/SiO2-TMPTA colloidal photonic crystals

    Science.gov (United States)

    Tian, Yu; Zhang, Jing; Liu, Si-Si; Yang, Shengyang; Yin, Su-Na; Wang, Cai-Feng; Chen, Li; Chen, Su

    2016-07-01

    An operable strategy for the construction of dual-reflex optical code materials from bilayer or Janus-structure colloidal photonic crystals (CPCs) has been established in this work. In this process, monodispersed submicrometer polystryene@poly(2-hydroxyethyl methacrylate-co-acrylic acid) hydrogel microspheres with soft-shell/hard-core structure and monodispersed colloidal silica spheres were fabricated. These two kinds of colloidal units can be facilely integrated into a single material without optical signal interference because they are well isolated for the immiscibility between water and ethoxylated trimethylolpropane triacrylate (TMPTA) and the upper layer of SiO2-TMPTA is a kind of transparent. Moreover, diverse optical code series with different dual photonic bandgaps can be obtained via tuning the colloid sizes. Compared to the conventional single-reflex CPCs, the as-prepared dual-reflex optical code materials represented high information capacity in encoding process. More interesting, delicate code pattern has been also achieved on the optical film via the silk-screen printing technique, which will greatly extend the dual-reflex optical code materials to practical uses in areas containing bio-encoding, anti-counterfeiting, and flexible displays.

  6. Low-loss transmission band in photonic crystal waveguides with sharp cutoff at a frequency below the bandgap

    NARCIS (Netherlands)

    Krüger, A.C.; Zhang, M.; Groothoff, N.; Malureanu, R.; Kristensen, M.

    2011-01-01

    We present TE transmission measurements of photonic crystal waveguides with high hole radius to period ratio r/¿ = 0.388. This geometry introduces a unique low loss transmission band in addition to the traditional PhC guiding band and very sharp transmission edges for devices with a length of 50 µm

  7. Preparation and photonic bandgap properties of Na1/2Bi1/2TiO3 inverse opal photonic crystals

    International Nuclear Information System (INIS)

    Yang Zhengwen; Zhou Ji; Huang Xueguang; Xie Qin; Fu Ming; Li Bo; Li Longtu

    2009-01-01

    The Na 1/2 Bi 1/2 TiO 3 (NBT) inverse opal photonic crystals were prepared by the self-assembly technique in combination with a sol-gel method. In the preparation process, NBT precursors were filled into the interstices of the opal template assembled by monodispersive polystyrene microspheres. The polystyrene template was then removed by calcination at 800 deg. C for 5 h, meanwhile, a perovskite NBT inverse opal photonic crystal was formed. An optical micrograph shows that the NBT inverse opals reflect green-yellow light strongly. Moreover, a photonic band gap was observed by reflective spectra of NBT sample

  8. Low-loss transmission band in photonic crystal waveguides with sharp cutoff at a frequency below the bandgap

    DEFF Research Database (Denmark)

    Krüger, Asger Christian; Zhang, Min; Groothoff, Nathaniel

    2011-01-01

    We present TE transmission measurements of photonic crystal waveguides with high hole radius to period ratio r/Λ=0.388. This geometry introduces a unique low loss transmission band in addition to the traditional PhC guiding band and very sharp transmission edges for devices with a length of 50 μm...... or longer. Finite difference time domain and plane wave expansion simulations confirm the results and show that the sharpness of the cutoffs can be explained by the spectral shape of the guiding mode in the band diagram....

  9. Neodymium-doped phosphate fiber lasers with an all-solid microstructured inner cladding.

    Science.gov (United States)

    Zhang, Guang; Zhou, Qinling; Yu, Chunlei; Hu, Lili; Chen, Danping

    2012-06-15

    We report on high-power fiber lasers based on index-guiding, all-solid neodymium-doped (Nd-doped) phosphate photonic crystal fiber (PCF) with a hexagonal-shaped inner cladding. The optimum fiber laser with a 36 cm length active fiber, generated up to 7.92 W output power at 1053 nm, which benefited from a high absorption coefficient for pump power due to its noncircular inner cladding. The guiding properties of the all-solid PCF were also investigated. A stable mode with a donut-shaped profile and a power-dependent laser beam quality have been observed experimentally and analyzed.

  10. A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Prelas, M.A.

    1996-01-24

    This report describes progress made to develop a high bandgap photovoltaic materials for direct conversion to electricity of excimer radiation produced by fission energy pumped laser. This report summarizes the major achievements in sections. The first section covers n-type diamond. The second section covers forced diffusion. The third section covers radiation effects. The fourth section covers progress in Schottky barrier and heterojunction photovoltaic cells. The fifth section covers cell and reactor development.

  11. Coupled-resonator-induced plasmonic bandgaps.

    Science.gov (United States)

    Wang, Yujia; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

    2017-10-15

    By drawing an analogy with the conventional photonic crystals, the plasmonic bandgaps have mainly employed the periodic metallic structures, named as plasmonic crystals. However, the sizes of the plasmonic crystals are much larger than the wavelengths, and the large sizes considerably decrease the density of the photonic integration circuits. Here, based on the coupled-resonator effect, the plasmonic bandgaps are experimentally realized in the subwavelength waveguide-resonator structure, which considerably decreases the structure size to subwavelength scales. An analytic model and the phase analysis are established to explain this phenomenon. Both the experiment and simulation show that the plasmonic bandgap structure has large fabrication tolerances (>20%). Instead of the periodic metallic structures in the bulky plasmonic crystals, the utilization of the subwavelength plasmonic waveguide-resonator structure not only significantly shrinks the bandgap structure to be about λ 2 /13, but also expands the physics of the plasmonic bandgaps. The subwavelength dimension, together with the waveguide configuration and robust realization, makes the bandgap structure easy to be highly integrated on chips.

  12. Modeling all-solid-state Li-ion batteries

    NARCIS (Netherlands)

    Danilov, D.; Niessen, R.A.H.; Notten, P.H.L.

    2011-01-01

    A mathematical model for all-solid-state Li-ion batteries is presented. The model includes the charge transfer kinetics at the electrode/electrolyte interface, diffusion of lithium in the intercalation electrode, and diffusion and migration of ions in the electrolyte. The model has been applied to

  13. Facilitated ion transport in all-solid-state flexible supercapacitors.

    Science.gov (United States)

    Choi, Bong Gill; Hong, Jinkee; Hong, Won Hi; Hammond, Paula T; Park, HoSeok

    2011-09-27

    The realization of highly flexible and all-solid-state energy-storage devices strongly depends on both the electrical properties and mechanical integrity of the constitutive materials and the controlled assembly of electrode and solid electrolyte. Herein we report the preparation of all-solid-state flexible supercapacitors (SCs) through the easy assembly of functionalized reduced graphene oxide (f-RGO) thin films (as electrode) and solvent-cast Nafion electrolyte membranes (as electrolyte and separator). In particular, the f-RGO-based SCs (f-RGO-SCs) showed a 2-fold higher specific capacitance (118.5 F/g at 1 A/g) and rate capability (90% retention at 30 A/g) compared to those of all-solid-state graphene SCs (62.3 F/g at 1A/g and 48% retention at 30 A/g). As proven by the 4-fold faster relaxation of the f-RGO-SCs than that of the RGO-SCs and more capacitive behavior of the former at the low-frequency region, these results were attributed to the facilitated ionic transport at the electrical double layer by means of the interfacial engineering of RGO by Nafion. Moreover, the superiority of all-solid-state flexible f-RGO-SCs was demonstrated by the good performance durability under the 1000 cycles of charging and discharging due to the mechanical integrity as a consequence of the interconnected networking structures. Therefore, this research provides new insight into the rational design and fabrication of all-solid-state flexible energy-storage devices as well as the fundamental understanding of ion and charge transport at the interface. © 2011 American Chemical Society

  14. All solid state pulsed power system for water discharge

    OpenAIRE

    Sakugawa, Takashi; Yamaguchi, Takahiro; Yamamoto, Kunihiro; Kiyan, Tsuyoshi; Namihira, Takao; Katsuki, Sunao; Akiyama, Hidenori; サクガワ, タカシ; ヤマグチ, タカヒロ; ヤマモト, クニヒロ; キヤン, ツヨシ; ナミヒラ, タカオ; カツキ, スナオ; アキヤマ, ヒデノリ; 佐久川, 貴志

    2005-01-01

    Pulsed power has been used to produce non-thermal plasmas in gases that generate a high electric field at the tip of streamer discharges, where high energy electrons, free radicals, and ozone are produced. Recently, all solid state pulsed power generators, which are operated with high repetition rate, long lifetime and high reliability, have been developed for industrial applications, such as high repetition rate pulsed gas lasers, high energy density plasma (EUV sources) and water discharges...

  15. Highly flexible and all-solid-state paperlike polymer supercapacitors.

    Science.gov (United States)

    Meng, Chuizhou; Liu, Changhong; Chen, Luzhuo; Hu, Chunhua; Fan, Shoushan

    2010-10-13

    In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible energy-storage devices for wearable electronics. Here we demonstrate a novel kind of ultrathin all-solid-state supercapacitor configuration with an extremely simple process using two slightly separated polyaniline-based electrodes well solidified in the H(2)SO(4)-polyvinyl alcohol gel electrolyte. The thickness of the entire device is much comparable to that of a piece of commercial standard A4 print paper. Under its highly flexible (twisting) state, the integrate device shows a high specific capacitance of 350 F/g for the electrode materials, well cycle stability after 1000 cycles and a leakage current of as small as 17.2 μA. Furthermore, due to its polymer-based component structure, it has a specific capacitance of as high as 31.4 F/g for the entire device, which is more than 6 times that of current high-level commercial supercapacitor products. These highly flexible and all-solid-state paperlike polymer supercapacitors may bring new design opportunities of device configuration for energy-storage devices in the future wearable electronic area.

  16. Assessment of all-solid-state lithium-ion batteries

    Science.gov (United States)

    Braun, P.; Uhlmann, C.; Weiss, M.; Weber, A.; Ivers-Tiffée, E.

    2018-07-01

    All-solid-state lithium-ion batteries (ASSBs) are considered as next generation energy storage systems. A model might be very useful, which describes all contributions to the internal cell resistance, enables an optimization of the cell design, and calculates the performance of an open choice of cell architectures. A newly developed one-dimensional model for ASSBs is presented, based on a design concept which employs the use of composite electrodes. The internal cell resistance is calculated by linking two-phase transmission line models representing the composite electrodes with an ohmic resistance representing the solid electrolyte (separator). Thereby, electrical parameters, i.e. ionic and electronic conductivity, electrochemical parameters, i.e. charge-transfer resistance at interfaces and lithium solid-state diffusion, and microstructure parameters, i.e. electrode thickness, particle size, interface area, phase composition and tortuosity, are considered as the most important material and design parameters. Subsequently, discharge curves are simulated, and energy- and power-density characteristics of all-solid-state cell architectures are calculated. These model calculations are discussed and compared with experimental data from literature for a high power LiCoO2-Li10GeP2S12/Li10GeP2S12/Li4Ti5O12-Li10GeP2S12 cell.

  17. An all-solid-state lithium/polyaniline rechargeable cell

    Science.gov (United States)

    Li, Changzhi; Peng, Xinsheng; Zhang, Borong; Wang, Baochen

    1992-07-01

    The performance of an all-solid-state cell having a lithium negative electrode, a modified polyethylene oxide (PEO)-epoxy resin (ER) electrolyte, and a polyaniline (PAn) positive electrode has been studied using cyclic voltammetry, charge/discharge cycling, and polarization curves at various temperatures. The redox reaction of the PAn electrode at the PAn/modified PEO-ER interface exhibits good reversibility. At 50-80 C, the Li/PEO-ER-LiClO4/PAn cell shows more than 40 charge/discharge cycles, 90 percent charge/discharge efficiency, and 54 W h kg discharge energy density (on PAn weight basis) at 50 micro-A between 2 and 4 V. The polarization performance of the battery improves steadily with increase in temperature.

  18. All solid-state SBS phase conjugate mirror

    Science.gov (United States)

    Dane, C.B.; Hackel, L.A.

    1999-03-09

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  19. A New All Solid State Approach to Gaseous Pollutant Detection

    Science.gov (United States)

    Brown, V.; Tamstorf, K.

    1971-01-01

    Recent efforts in our laboratories have concentrated on the development of an all solid state gas sensor, by combining solid electrolyte (ion exchange membrane) technology with advanced thin film deposition processes. With the proper bias magnitude and polarity these miniature electro-chemical,cells show remarkable current responses for many common pollution gases. Current activity is now focused on complementing a multiple array (matrix) of these solid state sensors, with a digital electronic scanner device possessing "scan-compare-identify-alarm: capability. This innovative approach to multi-component pollutant gas analysis may indeed be the advanced prototype for the "third generation" class of pollution analysis instrumentation so urgently needed in the decade ahead.

  20. All-solid-state reference electrodes based on conducting polymers.

    Science.gov (United States)

    Kisiel, Anna; Marcisz, Honorata; Michalska, Agata; Maksymiuk, Krzysztof

    2005-12-01

    A novel construction of solution free (pseudo)reference electrodes, compatible with all-solid-state potentiometric indicator electrodes, has been proposed. These electrodes use conducting polymers (CP): polypyrrole (PPy) or poly(3,4-ethylenedioxythiophene) (PEDOT). Two different arrangements have been tested: solely based on CP and those where the CP phase is covered with a poly(vinyl chloride) based outer membrane of tailored composition. The former arrangement was designed to suppress or compensate cation- and anion-exchange, using mobile perchlorate ions and poly(4-styrenesulfonate) or dodecylbenzenesulfonate anions as immobilized dopants. The following systems were used: (i) polypyrrole layers doped simultaneously by two kinds of anions, both mobile and immobilized in the polymer layer; (ii) bilayers of polypyrrole with anion exchanging inner layer and cation-exchanging outer layer; (iii) polypyrrole doped by surfactant dodecylbenzenesulfonate ions, which inhibit ion exchange on the polymer/solution interface. For the above systems, recorded potentials have been found to be practically independent of electrolyte concentration. The best results, profound stability of potentials, have been obtained for poly(3,4-ethylenedioxythiophene) or polypyrrole doped by poly(4-styrenesulfonate) anions covered by a poly(vinyl chloride) based membrane, containing both anion- and cation-exchangers as well as solid potassium chloride and silver chloride with metallic silver. Differently to the cases (i)-(iii) these electrodes are much less sensitive to the influence of redox and pH interferences. This arrangement has been also characterized using electrochemical impedance spectroscopy and chronopotentiometry.

  1. A compact, all solid-state LC high voltage generator.

    Science.gov (United States)

    Fan, Xuliang; Liu, Jinliang

    2013-06-01

    LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

  2. Development of all-solid-state flash x-ray generator with photoconductive semiconductor switches

    Energy Technology Data Exchange (ETDEWEB)

    Xun, Ma; Jianjun, Deng; Hongwei, Liu; Jianqiang, Yuan; Jinfeng, Liu; Bing, Wei; Yanling, Qing; Wenhui, Han; Lingyun, Wang; Pin, Jiang; Hongtao, Li [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAEP, P.O. Box 919-108, Mianyang 621900 (China)

    2014-09-15

    A compact, low-jitter, and high repetitive rate all-solid-state flash x-ray generator making use of photo conductive semiconductor switches was developed recently for the diagnostic purpose of some hydrokinetical experiments. The generator consisted of twelve stages of Blumlein pulse forming networks, and an industrial cold cathode diode was used to generate intense x-ray radiations with photon energy up to 220 keV. Test experiments showed that the generator could produce >1 kA electron beam currents and x-ray pulses with ∼40 ns duration under 100 Hz repetitive rates at least (limited by the triggering laser on hand), also found was that the delay time of the cathode explosive emission is crucial to the energy transfer efficiency of the whole system. In addition, factors affecting the diode impedance, how the switching synchronization and diode impedance determining the allowable operation voltage were discussed.

  3. Development of all-solid-state flash x-ray generator with photoconductive semiconductor switches.

    Science.gov (United States)

    Xun, Ma; Jianjun, Deng; Hongwei, Liu; Jianqiang, Yuan; Jinfeng, Liu; Bing, Wei; Yanling, Qing; Wenhui, Han; Lingyun, Wang; Pin, Jiang; Hongtao, Li

    2014-09-01

    A compact, low-jitter, and high repetitive rate all-solid-state flash x-ray generator making use of photo conductive semiconductor switches was developed recently for the diagnostic purpose of some hydrokinetical experiments. The generator consisted of twelve stages of Blumlein pulse forming networks, and an industrial cold cathode diode was used to generate intense x-ray radiations with photon energy up to 220 keV. Test experiments showed that the generator could produce >1 kA electron beam currents and x-ray pulses with ~40 ns duration under 100 Hz repetitive rates at least (limited by the triggering laser on hand), also found was that the delay time of the cathode explosive emission is crucial to the energy transfer efficiency of the whole system. In addition, factors affecting the diode impedance, how the switching synchronization and diode impedance determining the allowable operation voltage were discussed.

  4. Materials Development for All-Solid-State Battery Electrolytes

    Science.gov (United States)

    Wang, Weimin

    Solid electrolytes in all solid-state batteries, provide higher attainable energy density and improved safety. Ideal solid electrolytes require high ionic conductivity, a high elastic modulus to prevent dendrite growth, chemical compatibility with electrodes, and ease of fabrication into thin films. Although various materials types, including polymers, ceramics, and composites, are under intense investigation, unifying design principles have not been identified. In this thesis, we study the key ion transport mechanisms in relation to the structural characteristics of polymers and glassy solids, and apply derived material design strategies to develop polymer-silica hybrid materials with improved electrolyte performance characteristics. Poly(ethylene) oxide-based solid electrolytes containing ceramic nanoparticles are attractive alternatives to liquid electrolytes for high-energy density Li batteries. We compare the effect of Li1.3Al0.3Ti 1.7(PO4)3 active nanoparticles, passive TiO 2 nanoparticles and fumed silica. Up to two orders of magnitude enhancement in ionic conductivity is observed for composites with active nanoparticles, attributed to cation migration through a percolating interphase region that develops around the active nanoparticles, even at low nanoparticle loading. We investigate the structural origin of elastic properties and ionic migration mechanisms in sodium borosilicate and sodium borogermanate glass electrolyte system. A new statistical thermodynamic reaction equilibrium model is used in combination with data from nuclear magnetic resonance and Brillouin light scattering measurements to determine network structural unit fractions. The highly coordinated structural units are found to be predominantly responsible for effective mechanical load transmission, by establishing three-dimensional covalent connectivity. A strong correlation exists between bulk modulus and the activation energy for ion conduction. We describe the activated process in

  5. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  6. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  7. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  8. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  9. Photonic bandgap fibers: theory and experiments

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Libori, Stig E. Barkou

    2000-01-01

    We will in this presentation address, show how the fiber cladding structure influences the resulting waveguiding properties. The core may be introduced by breaking the periodicity of the air holes at the center of the fiber. It has been demonstrated experimentally that this makes it possible...

  10. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  11. Ultrasensitive tunability of the direct bandgap of 2D InSe flakes via strain engineering

    Science.gov (United States)

    Li, Yang; Wang, Tianmeng; Wu, Meng; Cao, Ting; Chen, Yanwen; Sankar, Raman; Ulaganathan, Rajesh K.; Chou, Fangcheng; Wetzel, Christian; Xu, Cheng-Yan; Louie, Steven G.; Shi, Su-Fei

    2018-04-01

    InSe, a member of the layered materials family, is a superior electronic and optical material which retains a direct bandgap feature from the bulk to atomically thin few-layers and high electronic mobility down to a single layer limit. We, for the first time, exploit strain to drastically modify the bandgap of two-dimensional (2D) InSe nanoflakes. We demonstrated that we could decrease the bandgap of a few-layer InSe flake by 160 meV through applying an in-plane uniaxial tensile strain to 1.06% and increase the bandgap by 79 meV through applying an in-plane uniaxial compressive strain to 0.62%, as evidenced by photoluminescence (PL) spectroscopy. The large reversible bandgap change of ~239 meV arises from a large bandgap change rate (bandgap strain coefficient) of few-layer InSe in response to strain, ~154 meV/% for uniaxial tensile strain and ~140 meV/% for uniaxial compressive strain, representing the most pronounced uniaxial strain-induced bandgap strain coefficient experimentally reported in 2D materials. We developed a theoretical understanding of the strain-induced bandgap change through first-principles DFT and GW calculations. We also confirmed the bandgap change by photoconductivity measurements using excitation light with different photon energies. The highly tunable bandgap of InSe in the infrared regime should enable a wide range of applications, including electro-mechanical, piezoelectric and optoelectronic devices.

  12. Photonic crystals: towards nanoscale photonic devices

    National Research Council Canada - National Science Library

    Lourtioz, J.-M

    2005-01-01

    .... From this point of view, the emergence of photonic bandgap materials and photonic crystals at the end of the 1980s can be seen as a revenge to the benefit this time of optics and electromagnetism. In the same way as the periodicity of solid state crystals determines the energy bands and the conduction properties of electrons, the periodical structur...

  13. Below-bandgap photoreflection spectroscopy of semiconductor laser structures

    International Nuclear Information System (INIS)

    Sotnikov, Aleksandr E; Chernikov, Maksim A; Ryabushkin, Oleg A; Trubenko, P; Moshegov, N; Ovchinnikov, A

    2004-01-01

    A new method of modulated light reflection - below-bandgap photoreflection, is considered. Unlike the conventional photoreflection method, the proposed method uses optical pumping by photons of energy smaller than the bandgap of any layer of a semiconductor structure under study. Such pumping allows one to obtain the modulated reflection spectrum for all layers of the structure without excitation of photoluminescence. This method is especially promising for the study of wide-gap semiconductors. The results of the study of semiconductor structures used in modern high-power multimode semiconductor lasers are presented. (laser applications and other topics in quantum electronics)

  14. Thermally controlled mid-IR band-gap engineering in all-glass chalcogenide microstructured fibers: a numerical study

    DEFF Research Database (Denmark)

    Barh, Ajanta; Varshney, Ravi K.; Pal, Bishnu P.

    2017-01-01

    Presence of photonic band-gap (PBG) in an all-glass low refractive index (RI) contrast chalcogenide (Ch) microstructured optical fibers (MOFs) is investigated numerically. The effect of external temperature on the position of band-gap is explored to realize potential fiber-based wavelength filters....... Then the temperature sensitivity of band-gaps is investigated to design fiber-based mid-IR wavelength filters/sensors....

  15. Recent Developments of All-Solid-State Lithium Secondary Batteries with Sulfide Inorganic Electrolytes.

    Science.gov (United States)

    Xu, Ruochen; Zhang, Shengzhao; Wang, Xiuli; Xia, Yan; Xia, Xinhui; Wu, Jianbo; Gu, Changdong; Tu, Jiangping

    2018-04-20

    Due to the increasing demand of security and energy density, all-solid-state lithium ion batteries have become the promising next-generation energy storage devices to replace the traditional liquid batteries with flammable organic electrolytes. In this Minireview, we focus on the recent developments of sulfide inorganic electrolytes for all-solid-state batteries. The challenges of assembling bulk-type all-solid-state batteries for industrialization are discussed, including low ionic conductivity of the present sulfide electrolytes, high interfacial resistance and poor compatibility between electrolytes and electrodes. Many efforts have been focused on the solutions for these issues. Although some progresses have been achieved, it is still far away from practical application. The perspectives for future research on all-solid-state lithium ion batteries are presented. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Coupled Acoustic-Mechanical Bandgaps

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Kook, Junghwan

    2016-01-01

    medium and the presence of acoustic resonances. It is demonstrated that corrugation of the plate structure can introduce bending wave bandgaps and bandgaps in the acoustic domain in overlapping and audible frequency ranges. This effect is preserved also when taking the physical coupling between the two...... domains into account. Additionally, the coupling is shown to introduce extra gaps in the band structure due to modal interaction and the appearance of a cut-on frequency for the fundamental acoustic mode....

  17. Agile Photonic Crystals

    Science.gov (United States)

    2011-01-03

    75, pp. 3253-3256, Oct. 1995. [24] F. Benabid, J. C. Knight, and P. S. J. Russell, “Particle levitation and guidance in hollow-core photonic crystal...B. Mizaikoff, “Midinfrared sensors meet nanotechnology: Trace gas sensing with quantum cascade lasers inside photonic band-gap hollow waveguides

  18. All Solid State Optical Pulse Shaper for the OMEGA Laser Fusion Facility

    International Nuclear Information System (INIS)

    Okishev, A.V.; Skeldon, M.D.; Keck, R.L.; Seka, W.

    2000-01-01

    OAK-B135 All Solid State Optical Pulse Shaper for the OMEGA Laser Fusion Facility. The authors have developed an all-solid-state, compact, computer-controlled, flexible optical pulse shaper for the OMEGA laser facility. This pulse shaper produces high bandwidth, temporally shaped laser pulses that meet OMEGA requirements. The design is a significant simplification over existing technology with improved performance capabilities

  19. Efficient all solid-state UV source for satellite-based lidar applications.

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Darrell Jewell; Smith, Arlee Virgil

    2003-07-01

    A satellite-based UV-DIAL measurement system would allow continuous global monitoring of ozone concentration in the upper atmosphere. However such systems remain difficult to implement because aerosol-scattering return signals for satellite-based lidars are very weak. A suitable system must produce high-energy UV pulses at multiple wavelengths with very high efficiency. For example, a nanosecond system operating at 10 Hz must generate approximately 1 J per pulse at 308-320 nm. An efficient space-qualified wavelength-agile system based on a single UV source that can meet this requirement is probably not available using current laser technology. As an alternative, we're pursuing a multi-source approach employing all-solid-state modules that individually generate 300-320 nm light with pulse energies in the range of 50-200 mJ, with transform-limited bandwidths and good beam quality. Pulses from the individual sources can be incoherently summed to obtain the required single-pulse energy. These sources use sum-frequency mixing of the 532 nm second harmonic of an Nd:YAG pump laser with 731-803 nm light derived from a recently-developed, state-of-the-art, nanosecond optical parametric oscillator. Two source configurations are under development, one using extra-cavity sum-frequency mixing, and the other intra-cavity sum-frequency mixing. In either configuration, we hope to obtain sum-frequency mixing efficiency approaching 60% by carefully matching the spatial and temporal properties of the laser and OPO pulses. This ideal balance of green and near-IR photons requires an injection-seeded Nd:YAG pump-laser with very high beam quality, and an OPO exhibiting unusually high conversion efficiency and exceptional signal beam quality. The OPO employs a singly-resonant high-Fresnel-number image-rotating self-injection-seeded nonplanar-ring cavity that achieves pump depletion > 65% and produces signal beams with M{sup 2} {approx} 3 at pulse energies exceeding 50 mJ. Pump beam

  20. Efficient CsF interlayer for high and low bandgap polymer solar cell

    Science.gov (United States)

    Mitul, Abu Farzan; Sarker, Jith; Adhikari, Nirmal; Mohammad, Lal; Wang, Qi; Khatiwada, Devendra; Qiao, Qiquan

    2018-02-01

    Low bandgap polymer solar cells have a great deal of importance in flexible photovoltaic market to absorb sun light more efficiently. Efficient wide bandgap solar cells are always available in nature to absorb visible photons. The development and incorporation of infrared photovoltaics (IR PV) with wide bandgap solar cells can improve overall solar device performance. Here, we have developed an efficient low bandgap polymer solar cell with CsF as interfacial layer in regular structure. Polymer solar cell devices with CsF shows enhanced performance than Ca as interfacial layer. The power conversion efficiency of 4.5% has been obtained for PDPP3T based polymer solar cell with CsF as interlayer. Finally, an optimal thickness with CsF as interfacial layer has been found to improve the efficiency in low bandgap polymer solar cells.

  1. Lessons learned: from dye-sensitized solar cells to all-solid-state hybrid devices.

    Science.gov (United States)

    Docampo, Pablo; Guldin, Stefan; Leijtens, Tomas; Noel, Nakita K; Steiner, Ullrich; Snaith, Henry J

    2014-06-25

    The field of solution-processed photovoltaic cells is currently in its second spring. The dye-sensitized solar cell is a widely studied and longstanding candidate for future energy generation. Recently, inorganic absorber-based devices have reached new record efficiencies, with the benefits of all-solid-state devices. In this rapidly changing environment, this review sheds light on recent developments in all-solid-state solar cells in terms of electrode architecture, alternative sensitizers, and hole-transporting materials. These concepts are of general applicability to many next-generation device platforms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Freestanding mesoporous VN/CNT hybrid electrodes for flexible all-solid-state supercapacitors.

    Science.gov (United States)

    Xiao, Xu; Peng, Xiang; Jin, Huanyu; Li, Tianqi; Zhang, Chengcheng; Gao, Biao; Hu, Bin; Huo, Kaifu; Zhou, Jun

    2013-09-25

    High-performance all-solid-state supercapacitors (SCs) are fabricated based on thin, lightweight, and flexible freestanding MVNN/CNT hybrid electrodes. The device shows a high volume capacitance of 7.9 F/cm(3) , volume energy and power density of 0.54 mWh/cm(3) and 0.4 W/cm(3) at a current density of 0.025 A/cm(3) . By being highly flexible, environmentally friendly, and easily connectable in series and parallel, the all-solid-state SCs promise potential applications in portable/wearable electronics. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. High-reflective colorful films fabricated by all-solid multi-layer cholesteric structures

    Science.gov (United States)

    Li, Y.; Luo, D.

    2018-02-01

    We demonstrate all-solid-state film with high-reflectivity based on cholesteric template. The adhesive (NOA81) is both filler and an adhesive, which can be avoids interfacial losses. The reflected right- and left-circularly polarized light has been developed by roll-to-roll method, and the reflectance of the films is more than 78%. Here, the all-solid film was used in distribute feedback laser with dye-doped. In addition, this films also used in include flexible reflective display, color pixels in digital photographs, printing and colored cladding of variety of objects.

  4. All-solid-state flexible ultrathin micro-supercapacitors based on graphene.

    Science.gov (United States)

    Niu, Zhiqiang; Zhang, Li; Liu, Lili; Zhu, Bowen; Dong, Haibo; Chen, Xiaodong

    2013-08-07

    Flexible, compact, ultrathin and all-solid-state micro-supercapacitors are prepared by coating H₃PO₄/PVA gel electrolyte onto micro-patterned rGO interdigitated electrodes prepared by combining photolithography with selective electrophoretic deposition. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Efficient all solid-state continuous-wave yellow-orange light source

    DEFF Research Database (Denmark)

    Janousek, Jiri; Johansson, Sandra; Tidemand-Lichtenberg, Peter

    2005-01-01

    We present highly efficient sum-frequency generation between two CW IR lasers using periodically poled KTP. The system is based on the 1064 and 1342 nm laser-lines of two Nd:YVO4 lasers. This is an all solid-state light source in the yellow-orange spectral range. The system is optimized in terms ...

  6. Printed all-solid flexible microsupercapacitors: towards the general route for high energy storage devices

    International Nuclear Information System (INIS)

    Wang, Ye; Shi, Yumeng; Zhao, Cheng Xi; Wong, Jen It; Yang, Hui Ying; Sun, Xiao Wei

    2014-01-01

    A novel method for fabricating all-solid flexible microsupercapacitors (MSCs) was proposed and developed by utilizing screen printing technology. A typical printed MSC is composed of a printed Ag electrode, MnO 2 /onion-like carbon (MnO 2 /OLC) as active material and a polyvinyl alcohol:H 3 PO 4 (PVA:H 3 PO 4 ) as solid electrolyte. A capacity of 7.04 mF cm −2 was achieved for the screen printed MnO 2 /OLC MSCs at a current density of 20 μA cm −2 . It also showed an excellent cycling stability, with 80% retention of the specific capacity after 1000 cycles. The printed all-solid flexible MSCs exhibited remarkably high mechanical flexibility when the devices were bent to a radius of 3.5 mm. In addition, all-solid MSCs were successfully demonstrated by screen printing technique on various substrates, such as silicon, glass and conventional printing paper. Moreover, the screen printing technique can be extended to other active materials, such as OLC and carbon nanotubes. This method provides a general route for printable all-solid flexible MSCs, which is compatible with the roll-to-roll process for various high performance active materials. (paper)

  7. High Reversibility of “Soft” Electrode Materials in All-Solid-State Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sakuda, Atsushi, E-mail: a.sakuda@aist.go.jp; Takeuchi, Tomonari, E-mail: a.sakuda@aist.go.jp; Shikano, Masahiro; Sakaebe, Hikari; Kobayashi, Hironori [Department of Energy and Environment, Research Institute for Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda (Japan)

    2016-05-10

    All-solid-state batteries using inorganic solid electrolytes (SEs) are considered to be ideal batteries for electric vehicles and plug-in hybrid electric vehicles because they are potentially safer than conventional lithium-ion batteries (LIBs). In addition, all-solid-state batteries are expected to have long battery life owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy density (more than 300 Wh kg{sup −1}) secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li{sub 3}NbS{sub 4}, have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric-energy density of conventional LIBs. Favorable solid–solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to give rise to cracks during fabrication and/or charge–discharge processes. Here, we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid–solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approximately 400 mAh g{sup −1} suggesting that the lithium niobium sulfide electrode charged and discharged without

  8. High Reversibility of Soft Electrode Materials in All-solid-state Batteries

    Directory of Open Access Journals (Sweden)

    Atsushi eSakuda

    2016-05-01

    Full Text Available All-solid-state batteries using inorganic solid electrolytes (SEs are considered to be ideal batteries for electric vehicles (EVs and plug-in hybrid electric vehicles (PHEVs because they are potentially safer than conventional lithium-ion batteries (LIBs. In addition, all-solid-state batteries are expected to have long battery lives owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy (more than 300 Wh kg-1 secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li3NbS4, have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric energy density of conventional LIBs.Favorable solid-solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to be given rise to cracks during fabrication and/or charge-discharge processes. Here we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid-solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approx. 400 mAh g-1, suggesting that the lithium niobium sulfide electrode charged and discharged without experiencing

  9. High Reversibility of “Soft” Electrode Materials in All-Solid-State Batteries

    International Nuclear Information System (INIS)

    Sakuda, Atsushi; Takeuchi, Tomonari; Shikano, Masahiro; Sakaebe, Hikari; Kobayashi, Hironori

    2016-01-01

    All-solid-state batteries using inorganic solid electrolytes (SEs) are considered to be ideal batteries for electric vehicles and plug-in hybrid electric vehicles because they are potentially safer than conventional lithium-ion batteries (LIBs). In addition, all-solid-state batteries are expected to have long battery life owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy density (more than 300 Wh kg −1 ) secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li 3 NbS 4 , have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric-energy density of conventional LIBs. Favorable solid–solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to give rise to cracks during fabrication and/or charge–discharge processes. Here, we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid–solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approximately 400 mAh g −1 suggesting that the lithium niobium sulfide electrode charged and discharged without experiencing

  10. Two-Dimentional Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Dridi, Kim

    1999-01-01

    possible a novel class of optical microcavities, whereas line defects make possible a novel class of waveguides. In this paper we will analyze two-dimensional photonic crystal waveguides based on photonic crystals with rods arranged on a triangular and a square lattice using a plane-wave expansion method......In the recent years a new class of periodic high-index contrast dielectric structures, known as photonic bandgap structures, has been discovered. In these structures frequency intervals, known as photonic bandgaps, where propagation of electromagnetic waves is not allowed, exist due to the periodic...... dielectric function. This is analogous to semiconductors, where electronic bandgaps exist due to the periodic arrangement of atoms. As is also the case for semiconductor structures, photonic bandgap structures may become of even greater value when defects are introduced. In particular, point defects make...

  11. Soft switching circuit to improve efficiency of all solid-state Marx modulator for DBDs

    Science.gov (United States)

    Liqing, TONG; Kefu, LIU; Yonggang, WANG

    2018-02-01

    For an all solid-state Marx modulator applied in dielectric barrier discharges (DBDs), hard switching results in a very low efficiency. In this paper, a series resonant soft switching circuit, which series an inductance with DBD capacitor, is proposed to reduce the power loss. The power loss of the all circuit status with hard switching was analyzed, and the maximum power loss occurred during discharging at the rising and falling edges. The power loss of the series resonant soft switching circuit was also presented. A comparative analysis of the two circuits determined that the soft switching circuit greatly reduced power loss. The experimental results also demonstrated that the soft switching circuit improved the power transmission efficiency of an all solid-state Marx modulator for DBDs by up to 3 times.

  12. All-solid-state lithium-ion microbatteries: a review of various three-dimensional concepts

    Energy Technology Data Exchange (ETDEWEB)

    Oudenhoven, Jos F.M.; Baggetto, Loic; Notten, Peter H.L. [Eindhoven University of Technology, Department of Chemistry and Chemical Engineering, Postbus 513, 5600 MB Eindhoven (Netherlands)

    2011-01-01

    With the increasing importance of wireless microelectronic devices the need for on-board power supplies is evidently also increasing. Possible candidates for microenergy storage devices are planar all-solid-state Li-ion microbatteries, which are currently under development by several start-up companies. However, to increase the energy density of these microbatteries further and to ensure a high power delivery, three-dimensional (3D) designs are essential. Therefore, several concepts have been proposed for the design of 3D microbatteries and these are reviewed. In addition, an overview is given of the various electrode and electrolyte materials that are suitable for 3D all-solid-state microbatteries. Furthermore, methods are presented to produce films of these materials on a nano- and microscale. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Sub-micrometer-thick all-solid-state supercapacitors with high power and energy densities

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fanhui [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250061 (China); Ding, Yi [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250061 (China); Shandong Applied Research Center for Gold Technology (Au-SDARC), Yantai 264005 (China)

    2011-09-15

    A sub-micrometer-thick, flexible, all-solid-state supercapacitor is fabricated. Through simultaneous realization of high dispersity of pseudocapacitance materials and quick electrode response, the hybrid nanostructures show enhanced volumetric capacitance and excellent stability, as well as very high power and energy densities. This suggests their potential as next-generation, high-performance energy conversion and storage devices for wearable electronics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

    Science.gov (United States)

    Bao, Junjie; Shi, Gaojian; Tao, Can; Wang, Chao; Zhu, Chen; Cheng, Liang; Qian, Gang; Chen, Chunhua

    2018-06-01

    Four kinds of polycarbonate-based polyurethane with 8-14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10-4 S cm-1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g-1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

  15. Resonant add-drop filter based on a photonic quasicrystal

    DEFF Research Database (Denmark)

    Romero-Vivas, J.; Chigrin, D. N.; Lavrinenko, Andrei

    2005-01-01

    We present a numerical study of optical properties of an octagonal quasi-periodic lattice of dielectric rods. We report on a complete photonic bandgap in TM polarization up to extremely low dielectric constants of rods. The first photonic bandgap remains open down to dielectric constant as small ...

  16. Electronic structure characterization and bandgap engineering of solar hydrogen materials

    International Nuclear Information System (INIS)

    Guo, Jinghua

    2007-01-01

    Bandgap, band edge positions as well as the overall band structure of semiconductors are of crucial importance in photoelectrochemical and photocatalytic applications. The energy position of the band edge level can be controlled by the electronegativity of the dopants, the pH of the solution (flatband potential variation of 60 mV per pH unit), as well as by quantum confinement effects. Accordingly, band edges and bandgap can be tailored to achieve specific electronic, optical or photocatalytic properties. Synchrotron radiation with photon energy at or below 1 keV is giving new insight into such areas as condensed matter physics and extreme ultraviolet optics technology. In the soft x-ray region, the question tends to be, what are the electrons doing as they migrated between the atoms. In this paper, I will present a number of soft x-ray spectroscopic study of nanostructured 3d metal compounds Fe 2 O 3 and ZnO

  17. Spatial filtering with photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maigyte, Lina [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Staliunas, Kestutis [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona 08010 (Spain)

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  18. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  19. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-07-03

    Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

  20. 2-Photon tandem device for water splitting

    DEFF Research Database (Denmark)

    Seger, Brian; Castelli, Ivano Eligio; Vesborg, Peter Christian Kjærgaard

    2014-01-01

    Within the field Of photocatalytic water splitting there are several strategies to achieve the goal of efficient and cheap photocatalytic water splitting. This work examines one particular strategy by focusing on monolithically stacked, two-photon photoelectrochemical cells. The overall aim...... for photocatalytic water splitting by using a large bandgap photocathode and a low bandgap photoanode with attached protection layers....

  1. Modelling of photonic crystal fibres

    DEFF Research Database (Denmark)

    Knudsen, Erik

    2003-01-01

    , as well as a honeycomb bandgap fibre and the first analysis of semi-periodic layered air-hole fibres. Using the modelling framework established as a basis, we provide an analysis of microbend loss, by regarding displacement of a fibre core as a stationary stochastic process, inducing mismatch between......In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...

  2. Fano resonance in anodic aluminum oxide based photonic crystals.

    Science.gov (United States)

    Shang, Guo Liang; Fei, Guang Tao; Zhang, Yao; Yan, Peng; Xu, Shao Hui; Ouyang, Hao Miao; Zhang, Li De

    2014-01-08

    Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.

  3. Fiber-based all-solid-state flexible supercapacitors for self-powered systems.

    Science.gov (United States)

    Xiao, Xu; Li, Tianqi; Yang, Peihua; Gao, Yuan; Jin, Huanyu; Ni, Weijian; Zhan, Wenhui; Zhang, Xianghui; Cao, Yuanzhi; Zhong, Junwen; Gong, Li; Yen, Wen-Chun; Mai, Wenjie; Chen, Jian; Huo, Kaifu; Chueh, Yu-Lun; Wang, Zhong Lin; Zhou, Jun

    2012-10-23

    All-solid-state flexible supercapacitors based on a carbon/MnO(2) (C/M) core-shell fiber structure were fabricated with high electrochemical performance such as high rate capability with a scan rate up to 20 V s(-1), high volume capacitance of 2.5 F cm(-3), and an energy density of 2.2 × 10(-4) Wh cm(-3). By integrating with a triboelectric generator, supercapacitors could be charged and power commercial electronic devices, such as a liquid crystal display or a light-emitting-diode, demonstrating feasibility as an efficient storage component and self-powered micro/nanosystems.

  4. Flexible all solid-state supercapacitors based on chemical vapor deposition derived graphene fibers.

    Science.gov (United States)

    Li, Xinming; Zhao, Tianshuo; Chen, Qiao; Li, Peixu; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Wei, Bingqing; Zhu, Hongwei

    2013-11-07

    Flexible all-solid-state supercapacitors based on graphene fibers are demonstrated in this study. Surface-deposited oxide nanoparticles are used as pseudo-capacitor electrodes to achieve high capacitance. This supercapacitor electrode has an areal capacitance of 42 mF cm(-2), which is comparable to the capacitance for fiber-based supercapacitors reported to date. During the bending and cycling of the fiber-based supercapacitor, the stability could be maintained without sacrificing the electrochemical performance, which provides a novel and simple way to develop flexible, lightweight and efficient graphene-based devices.

  5. Highly compressible and all-solid-state supercapacitors based on nanostructured composite sponge.

    Science.gov (United States)

    Niu, Zhiqiang; Zhou, Weiya; Chen, Xiaodong; Chen, Jun; Xie, Sishen

    2015-10-21

    Based on polyaniline-single-walled carbon nanotubes -sponge electrodes, highly compressible all-solid-state supercapacitors are prepared with an integrated configuration using a poly(vinyl alcohol) (PVA)/H2 SO4 gel as the electrolyte. The unique configuration enables the resultant supercapacitors to be compressed as an integrated unit arbitrarily during 60% compressible strain. Furthermore, the performance of the resultant supercapacitors is nearly unchanged even under 60% compressible strain. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. All-solid-state supercapacitors on silicon using graphene from silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bei; Ahmed, Mohsin; Iacopi, Francesca, E-mail: f.iacopi@griffith.edu.au [Environmental Futures Research Institute, Griffith University, Nathan 4111 (Australia); Wood, Barry [Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia 4072 (Australia)

    2016-05-02

    Carbon-based supercapacitors are lightweight devices with high energy storage performance, allowing for faster charge-discharge rates than batteries. Here, we present an example of all-solid-state supercapacitors on silicon for on-chip applications, paving the way towards energy supply systems embedded in miniaturized electronics with fast access and high safety of operation. We present a nickel-assisted graphitization method from epitaxial silicon carbide on a silicon substrate to demonstrate graphene as a binder-free electrode material for all-solid-state supercapacitors. We obtain graphene electrodes with a strongly enhanced surface area, assisted by the irregular intrusion of nickel into the carbide layer, delivering a typical double-layer capacitance behavior with a specific area capacitance of up to 174 μF cm{sup −2} with about 88% capacitance retention over 10 000 cycles. The fabrication technique illustrated in this work provides a strategic approach to fabricate micro-scale energy storage devices compatible with silicon electronics and offering ultimate miniaturization capabilities.

  7. Nanocarbon-Based Materials for Flexible All-Solid-State Supercapacitors.

    Science.gov (United States)

    Lv, Tian; Liu, Mingxian; Zhu, Dazhang; Gan, Lihua; Chen, Tao

    2018-04-01

    Because of the rapid development of flexible electronics, it is important to develop high-performance flexible energy-storage devices, such as supercapacitors and metal-ion batteries. Compared with metal-ion batteries, supercapacitors exhibit higher power density, longer cycling life, and excellent safety, and they can be easily fabricated into all-solid-state devices by using polymer gel electrolytes. All-solid-state supercapacitors (ASSSCs) have the advantages of being lightweight and flexible, thus showing great potential to be used as power sources for flexible portable electronics. Because of their high specific surface area and excellent electrical and mechanical properties, nanocarbon materials (such as carbon nanotubes, graphene, carbon nanofibers, and so on) have been widely used as efficient electrode materials for flexible ASSSCs, and great achievements have been obtained. Here, the recent advances in flexible ASSSCs are summarized, from design strategies to fabrication techniques for nanocarbon electrodes and devices. Current challenges and future perspectives are also discussed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. All-solid state flexible supercapacitors based on graphene/polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Won; Choi, Bong Gill, E-mail: bgchoi@kangwon.ac.kr

    2015-06-01

    Recent advances in lightweight, flexible, and wearable electronic equipment has led to advancements in the development of sufficiently compact and flexible energy storage. A challenge remains to integrate the storage elements as closely as possible within a fully flexible device. Here, we demonstrate the fabrication of all-solid state flexible supercapacitors with the integration of two electrodes that consist of graphene/polymer composites. Robust conductive free-standing thin graphene/polymer composite electrodes were prepared through a simple “physical grinding” process. As-prepared composite electrodes store energy up to a reversible gravimetric capacitance of 90.6 F/g, at a constant current density of 0.5 A/g while also delivering long-term durability (90% retention) for excess of five-thousands of cycles. Notably, the enhancement of mechanical properties of supercapacitors enables them to maintain their electrochemical performance even when twisted or folded. This straightforward approach to the fabrication of fully flexible supercapacitors provides new design opportunities within wearable electronics and electrochemical applications. - Highlights: • All solid-sate supercapacitors were fabricated using graphene/polymer composite electrodes. • Supercapacitor devices show an excellent mechanical flexibility. • High electrochemical performances were demonstrated.

  9. Monolayer Nickel Cobalt Hydroxyl Carbonate for High Performance All-Solid-State Asymmetric Supercapacitors.

    Science.gov (United States)

    Zhao, Yufeng; Ma, Hongnan; Huang, Shifei; Zhang, Xuejiao; Xia, Meirong; Tang, Yongfu; Ma, Zi-Feng

    2016-09-07

    The emergence of atomically thick nanolayer materials, which feature a short ion diffusion channel and provide more exposed atoms in the electrochemical reactions, offers a promising occasion to optimize the performance of supercapacitors on the atomic level. In this work, a novel monolayer Ni-Co hydroxyl carbonate with an average thickness of 1.07 nm is synthesized via an ordinary one-pot hydrothermal route for the first time. This unique monolayer structure can efficiently rise up the exposed electroactive sites and facilitate the surface dependent electrochemical reaction processes, and thus results in outstanding specific capacitance of 2266 F g(-1). Based on this material, an all-solid-state asymmetric supercapacitor is developed adopting alkaline PVA (poly(vinyl alcohol)) gel (PVA/KOH) as electrolyte, which performs remarkable cycling stability (no capacitance fade after 19 000 cycles) together with promising energy density of 50 Wh kg(-1) (202 μWh cm(-2)) and high power density of 8.69 kW kg(-1) (35.1 mW cm(-2)). This as-assembled all-solid-state asymmetric supercapacitor (AASC) holds great potential in the field of portable energy storage devices.

  10. Sintered Cathodes for All-Solid-State Structural Lithium-Ion Batteries

    Science.gov (United States)

    Huddleston, William; Dynys, Frederick; Sehirlioglu, Alp

    2017-01-01

    All-solid-state structural lithium ion batteries serve as both structural load-bearing components and as electrical energy storage devices to achieve system level weight savings in aerospace and other transportation applications. This multifunctional design goal is critical for the realization of next generation hybrid or all-electric propulsion systems. Additionally, transitioning to solid state technology improves upon battery safety from previous volatile architectures. This research established baseline solid state processing conditions and performance benchmarks for intercalation-type layered oxide materials for multifunctional application. Under consideration were lithium cobalt oxide and lithium nickel manganese cobalt oxide. Pertinent characteristics such as electrical conductivity, strength, chemical stability, and microstructure were characterized for future application in all-solid-state structural battery cathodes. The study includes characterization by XRD, ICP, SEM, ring-on-ring mechanical testing, and electrical impedance spectroscopy to elucidate optimal processing parameters, material characteristics, and multifunctional performance benchmarks. These findings provide initial conditions for implementing existing cathode materials in load bearing applications.

  11. All-solid state flexible supercapacitors based on graphene/polymer composites

    International Nuclear Information System (INIS)

    Kim, Jung Won; Choi, Bong Gill

    2015-01-01

    Recent advances in lightweight, flexible, and wearable electronic equipment has led to advancements in the development of sufficiently compact and flexible energy storage. A challenge remains to integrate the storage elements as closely as possible within a fully flexible device. Here, we demonstrate the fabrication of all-solid state flexible supercapacitors with the integration of two electrodes that consist of graphene/polymer composites. Robust conductive free-standing thin graphene/polymer composite electrodes were prepared through a simple “physical grinding” process. As-prepared composite electrodes store energy up to a reversible gravimetric capacitance of 90.6 F/g, at a constant current density of 0.5 A/g while also delivering long-term durability (90% retention) for excess of five-thousands of cycles. Notably, the enhancement of mechanical properties of supercapacitors enables them to maintain their electrochemical performance even when twisted or folded. This straightforward approach to the fabrication of fully flexible supercapacitors provides new design opportunities within wearable electronics and electrochemical applications. - Highlights: • All solid-sate supercapacitors were fabricated using graphene/polymer composite electrodes. • Supercapacitor devices show an excellent mechanical flexibility. • High electrochemical performances were demonstrated

  12. All-solid-state supercapacitors on silicon using graphene from silicon carbide

    International Nuclear Information System (INIS)

    Wang, Bei; Ahmed, Mohsin; Iacopi, Francesca; Wood, Barry

    2016-01-01

    Carbon-based supercapacitors are lightweight devices with high energy storage performance, allowing for faster charge-discharge rates than batteries. Here, we present an example of all-solid-state supercapacitors on silicon for on-chip applications, paving the way towards energy supply systems embedded in miniaturized electronics with fast access and high safety of operation. We present a nickel-assisted graphitization method from epitaxial silicon carbide on a silicon substrate to demonstrate graphene as a binder-free electrode material for all-solid-state supercapacitors. We obtain graphene electrodes with a strongly enhanced surface area, assisted by the irregular intrusion of nickel into the carbide layer, delivering a typical double-layer capacitance behavior with a specific area capacitance of up to 174 μF cm"−"2 with about 88% capacitance retention over 10 000 cycles. The fabrication technique illustrated in this work provides a strategic approach to fabricate micro-scale energy storage devices compatible with silicon electronics and offering ultimate miniaturization capabilities.

  13. Single-mode, All-Solid-State Nd:YAG Laser Pumped UV Converter

    Science.gov (United States)

    Prasad, Narasimha S.; Armstrong, Darrell, J.; Edwards, William C.; Singh, Upendra N.

    2008-01-01

    In this paper, the status of a high-energy, all solid-state Nd:YAG laser pumped nonlinear optics based UV converter development is discussed. The high-energy UV transmitter technology is being developed for ozone sensing applications from space based platforms using differential lidar technique. The goal is to generate greater than 200 mJ/pulse with 10-50 Hz PRF at wavelengths of 308 nm and 320 nm. A diode-pumped, all-solid-state and single longitudinal mode Nd:YAG laser designed to provide conductively cooled operation at 1064 nm has been built and tested. Currently, this pump laser provides an output pulse energy of >1 J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of UV converter arrangement basically consists of an IR Optical Parametric Oscillator (OPO) and a Sum Frequency Generator (SFG) setups that are pumped by 532 nm wavelength obtained via Second Harmonic Generation (SHG). In this paper, the operation of an inter cavity SFG with CW laser seeding scheme generating 320 nm wavelength is presented. Efforts are underway to improve conversion efficiency of this mJ class UV converter by modifying the spatial beam profile of the pump laser.

  14. All-solid-state carbon nanotube torsional and tensile artificial muscles.

    Science.gov (United States)

    Lee, Jae Ah; Kim, Youn Tae; Spinks, Geoffrey M; Suh, Dongseok; Lepró, Xavier; Lima, Mácio D; Baughman, Ray H; Kim, Seon Jeong

    2014-05-14

    We report electrochemically powered, all-solid-state torsional and tensile artificial yarn muscles using a spinnable carbon nanotube (CNT) sheet that provides attractive performance. Large torsional muscle stroke (53°/mm) with minor hysteresis loop was obtained for a low applied voltage (5 V) without the use of a relatively complex three-electrode electromechanical setup, liquid electrolyte, or packaging. Useful tensile muscle strokes were obtained (1.3% at 2.5 V and 0.52% at 1 V) when lifting loads that are ∼25 times heavier than can be lifted by the same diameter human skeletal muscle. Also, the tensile actuator maintained its contraction following charging and subsequent disconnection from the power supply because of its own supercapacitor property at the same time. Possible eventual applications for the individual tensile and torsional muscles are in micromechanical devices, such as for controlling valves and stirring liquids in microfluidic circuits, and in medical catheters.

  15. Design and Characterisation of Solid Electrolytes for All-Solid-State Lithium Batteries

    DEFF Research Database (Denmark)

    Sveinbjörnsson, Dadi Þorsteinn

    The development of all-solid-state lithium batteries, in which the currently used liquid electrolytes are substituted for solid electrolyte materials, could lead to safer batteries offering higher energy densities and longer cycle lifetimes. Designing suitable solid electrolytes with sufficient...... chemical and electrochemical stability, high lithium ion conduction and negligible electronic conduction remains a challenge. The highly lithium ion conducting LiBH4-LiI solid solution is a promising solid electrolyte material. Solid solutions with a LiI content of 6.25%-50% were synthesised by planetary......-rich microstructures during ball milling is found to significantly influence the conductivity of the samples. The long-range diffusion of lithium ions was measured using quasi-elastic neutron scattering. The solid solutions are found to exhibit two-dimensional conduction in the hexagonal plane of the crystal structure...

  16. All-solid-state micro-supercapacitors based on inkjet printed graphene electrodes

    Science.gov (United States)

    Li, Jiantong; Mishukova, Viktoriia; Östling, Mikael

    2016-09-01

    The all-solid-state graphene-based in-plane micro-supercapacitors are fabricated simply through reliable inkjet printing of pristine graphene in interdigitated structure on silicon wafers to serve as both electrodes and current collectors, and a following drop casting of polymer electrolytes (polyvinyl alcohol/H3PO4). Benefiting from the printing processing, an attractive porous electrode microstructure with a large number of vertically orientated graphene flakes is observed. The devices exhibit commendable areal capacitance over 0.1 mF/cm2 and a long cycle life of over 1000 times. The simple and scalable fabrication technique for efficient micro-supercapacitors is promising for on-chip energy storage applications in emerging electronics.

  17. MnO2/MCMB electrocatalyst for all solid-state alkaline zinc-air cells

    International Nuclear Information System (INIS)

    Zhang, G.Q.; Zhang, X.G.

    2004-01-01

    Nanostructured MnO 2 /mesocarbon microbeads (MCMB) composite has been prepared successfully for use in zinc-air cell as electrocatalyst for oxygen reaction. The scanning electron microscope (SEM) images showed that the MnO 2 nanorods were formed and covered on the surface of MCMB in bird's nest morphology. X-ray diffraction (XRD) pattern indicated that the MnO 2 has the hollandite structure with a composition approximating KMn 8 O 16 . By the cathodic polarization curve tests, the nanostructured material demonstrated excellent electrocatalytic activity as a kind of oxygen electrode electrocatalyst compared with electrolytic MnO 2 . An all solid-state zinc-air cell has been fabricated with this material as electrocatalyst for oxygen electrode and potassium salt of cross-linked poly(acrylic acid) as an alkaline polymer gel electrolyte. The cell has good discharge characteristics at room temperature

  18. Development of a new all solid contact Cs"+ ion selective electrode

    International Nuclear Information System (INIS)

    Ramanjaneyulu, P.S.; Abha Naveen Kumar; Sharma, M.K.

    2017-01-01

    Studies were carried out to develop all solid contact cesium ion selective electrode with 25,27-bis(1-octyloxy)calix[4]arene-crown-6 as an ionophore. Polyaniline (PANI), deposited on Pt electrode by electrochemical method, was used as a transducer. Three different types of electrodes were made with variation in thickness of PANI film and gold nanoparticles doped PANI as transducers. The best response was observed with ISE having Au nanoparticles doped PANI as a transducer. The optimised ISE gave Nernstian response in the range 10"-"7 to 10"-"2 M with the slope of 55.0 ± 0.6 mV/decade of Cs"+. The response of ISE for Cs"+ is fairly constant above the pH 4. The developed ISE was successfully employed to determine Cs"+ in simulated high level nuclear waste solutions and CsCl spiked tap water samples. (author)

  19. Challenges and perspectives of garnet solid electrolytes for all solid-state lithium batteries

    Science.gov (United States)

    Liu, Qi; Geng, Zhen; Han, Cuiping; Fu, Yongzhu; Li, Song; He, Yan-bing; Kang, Feiyu; Li, Baohua

    2018-06-01

    Garnet Li7La3Zr2O12 (LLZO) solid electrolytes recently have attracted tremendous interest as they have the potential to enable all solid-state lithium batteries (ASSLBs) owing to high ionic conductivity (10-3 to 10-4 S cm-1), negligible electronic transport, wide potential window (up to 9 V), and good chemical stability. Here we present the key issues and challenges of LLZO in the aspects of ion conduction property, interfacial compatibility, and stability in air. First, different preparation methods of LLZO are reviewed. Then, recent progress about the improvement of ionic conductivity and interfacial property between LLZO and electrodes are presented. Finally, we list some emerging LLZO-based solid-state batteries and provide perspectives for further research. The aim of this review is to summarize the up-to-date developments of LLZO and lead the direction for future development which could enable LLZO-based ASSLBs.

  20. Lithium Azide as an Electrolyte Additive for All-Solid-State Lithium-Sulfur Batteries.

    Science.gov (United States)

    Eshetu, Gebrekidan Gebresilassie; Judez, Xabier; Li, Chunmei; Bondarchuk, Oleksandr; Rodriguez-Martinez, Lide M; Zhang, Heng; Armand, Michel

    2017-11-27

    Of the various beyond-lithium-ion battery technologies, lithium-sulfur (Li-S) batteries have an appealing theoretical energy density and are being intensely investigated as next-generation rechargeable lithium-metal batteries. However, the stability of the lithium-metal (Li°) anode is among the most urgent challenges that need to be addressed to ensure the long-term stability of Li-S batteries. Herein, we report lithium azide (LiN 3 ) as a novel electrolyte additive for all-solid-state Li-S batteries (ASSLSBs). It results in the formation of a thin, compact and highly conductive passivation layer on the Li° anode, thereby avoiding dendrite formation, and polysulfide shuttling. It greatly enhances the cycling performance, Coulombic and energy efficiencies of ASSLSBs, outperforming the state-of-the-art additive lithium nitrate (LiNO 3 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Review on solid electrolytes for all-solid-state lithium-ion batteries

    Science.gov (United States)

    Zheng, Feng; Kotobuki, Masashi; Song, Shufeng; Lai, Man On; Lu, Li

    2018-06-01

    All-solid-state (ASS) lithium-ion battery has attracted great attention due to its high safety and increased energy density. One of key components in the ASS battery (ASSB) is solid electrolyte that determines performance of the ASSB. Many types of solid electrolytes have been investigated in great detail in the past years, including NASICON-type, garnet-type, perovskite-type, LISICON-type, LiPON-type, Li3N-type, sulfide-type, argyrodite-type, anti-perovskite-type and many more. This paper aims to provide comprehensive reviews on some typical types of key solid electrolytes and some ASSBs, and on gaps that should be resolved.

  2. Heterogeneous all-solid multicore fiber based multipath Michelson interferometer for high temperature sensing.

    Science.gov (United States)

    Duan, Li; Zhang, Peng; Tang, Ming; Wang, Ruoxu; Zhao, Zhiyong; Fu, Songnian; Gan, Lin; Zhu, Benpeng; Tong, Weijun; Liu, Deming; Shum, Perry Ping

    2016-09-05

    A compact high temperature sensor utilizing a multipath Michelson interferometer (MI) structure based on weak coupling multicore fiber (MCF) is proposed and experimentally demonstrated. The device is fabricated by program-controlled tapering the spliced region between single mode fiber (SMF) and a segment of MCF. After that, a spherical reflective structure is formed by arc-fusion splicing the end face of MCF. Theoretical analysis has been implemented for this specific multipath MI structure; beam propagation method based simulation and corresponding experiments were performed to investigate the effect of taper and spherical end face on system's performance. Benefiting from the multipath interferences and heterogeneous structure between the center core and surrounding cores of the all-solid MCF, an enhanced temperature sensitivity of 165 pm/°C up to 900°C and a high-quality interference spectrum with 25 dB fringe visibility were achieved.

  3. High efficiency single frequency 355 nm all-solid-state UV laser

    International Nuclear Information System (INIS)

    Xie, Xiaobing; Wei, Daikang; Ma, Xiuhua; Li, Shiguang; Liu, Jiqiao; Zhu, Xiaolei; Chen, Weibiao

    2016-01-01

    A novel conductively cooled high energy single-frequency 355 nm all-solid-state UV laser is presented based on sum-frequency mixing technique. In this system, a pulsed seeder laser at 1064 nm wavelength, modulated by an AOM, is directly amplified by the cascaded multi-stage hybrid laser amplifiers, and two LBO crystals are used for the SHG and SFG, finally a maximum UV pulse energy of 226 mJ at 355 nm wavelength is achieved with frequency-tripled conversion efficiency as high as 55%, the pulse width is around 12.2 ns at the repetition frequency of 30 Hz. The beam quality factor M 2 of the output UV laser is measured to be 2.54 and 2.98 respectively in two orthogonal directions. (paper)

  4. High Energy, Single-Mode, All-Solid-State and Tunable UV Laser Transmitter

    Science.gov (United States)

    Prasad, Narasimha S.; Singh, Upendra N.; Hovis, FLoyd

    2007-01-01

    A high energy, single mode, all solid-state Nd:YAG laser primarily for pumping an UV converter is developed. Greater than 1 J/pulse at 50 HZ PRF and pulse widths around 22 ns have been demonstrated. Higher energy, greater efficiency may be possible. Refinements are known and practical to implement. Technology Demonstration of a highly efficient, high-pulse-energy, single mode UV wavelength generation using flash lamp pumped laser has been achieved. Greater than 90% pump depletion is observed. 190 mJ extra-cavity SFG; IR to UV efficiency > 21% (> 27% for 1 mJ seed). 160 mJ intra-cavity SFG; IR to UV efficiency up to 24% Fluence laser is being refined to match or exceed the above UV converter results. Currently the Nd:YAG pump laser development is a technology demonstration. System can be engineered for compact packaging.

  5. Design of the all solid high-voltage power supply for a gyrotron body

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Yihua [School of Mathematics and Physics, University of South China, Hengyang, 421001 (China); Chen, Wenguang, E-mail: 430000485393@usc.edu.cn [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Hu, Bo [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Rao, Jun; Huang, Mei; Kang, Zihua; Feng, Kun [Southwestern Institute of Physics, Chengdu, 610041 (China); Huang, Jiaqi [School of Electrical Engineering, University of South China, Hengyang, 421001 (China)

    2017-04-15

    Highlights: • Completed design of all solid-state high-voltage power supply for gyrotron body on HL-2M ECRH. • Consist of 58 PSM modules and one BUCK module, controlled by DSP system. • Fabricated full voltage 35 kV, 200 mA BPS and tested in dummy load. • The BPS can operate in three modes: single pulse mode, multi-pulse modulation mode and the six-level preset mode. - Abstract: Gyrotron plays an important role in the research of electron cyclotron resonance heating (ECRH) on Tokomak. The high-frequency switched power supply technology and pulse step modulation (PSM) technology are used in the development of the all solid high-voltage body power supply (BPS) for 1 MW/105 GHz Gyrotron on ECRH system. Firstly, the basic structure of the BPS and its control system are introduced. Secondly, the software control algorithm of voltage stabilization and modulate method are developed. Finally, the design is verified by the experiments. The experimental results of the single pulse mode, the multi-pulse modulation mode and the six-level preset mode, are shown. The output voltage of the power supply can reach 35 kV and the current at about 200 mA, which are adjustable in the full range. The maximum modulation frequency can reach 1 kHz and the front edge of the pulse can be adjust from 0 to 3 ms and the accuracy of the output voltage is less than 100 V. The results show that the control method is feasible and can be applied to other high power microwave sources.

  6. Life Cycle Assessment and resource analysis of all-solid-state batteries

    International Nuclear Information System (INIS)

    Troy, Stefanie; Schreiber, Andrea; Reppert, Thorsten; Gehrke, Hans-Gregor; Finsterbusch, Martin; Uhlenbruck, Sven; Stenzel, Peter

    2016-01-01

    Highlights: • Laboratory scale production of an all-solid-state battery cell is assessed using Life Cycle Assessment. • The foremost share of overall emissions results from electricity consumption on site. • Possible improvement potential when upscaling production processes is investigated. • LCA results prove: early research stage products are not comparable to competing technologies at commercial stage. • Additional resource analysis shows: lanthanum, lithium and zirconium are critical materials. - Abstract: In this investigation the environmental impacts of the manufacturing processes of a new all-solid-state battery (SSB) concept in a pouch bag housing were assessed using the Life Cycle Assessment (LCA) methodology for the first time. To do so, the different production steps were investigated in detail, based on actual laboratory scale production processes. All in- and outputs regarding material and energy flows were collected and assessed. As LCA investigations of products in an early state of research and development usually result in comparatively higher results than those of mature technologies in most impact categories, potential future improvements of production processes and efficiency were considered by adding two concepts to the investigation. Apart from the laboratory production which depicts the current workflow, an idealized laboratory production and a possible industrial production were portrayed as well. The results indicate that electricity consumption plays a big role due to a lot of high temperature production steps. It needs to be improved for future industrial production. Also enhanced battery performance can strongly influence the results. Overall the laboratory scale results indeed improve strongly when assuming a careful use of resources, which will likely be a predominant target for industrial production. These findings therefore highlight hotspots and give improvement targets for future developments. It can also be deducted

  7. All-solid-state carbonate-selective electrode based on screen-printed carbon paste electrode

    International Nuclear Information System (INIS)

    Li, Guang; Lyu, Xiaofeng; Wang, Zhan; Rong, Yuanzhen; Hu, Ruifen; Wang, You; Luo, Zhiyuan

    2017-01-01

    A novel disposable all-solid-state carbonate-selective electrode based on a screen-printed carbon paste electrode using poly(3-octylthiophene-2,5-diyl) (POT) as an ion-to-electron transducer has been developed. The POT was dropped onto the reaction area of the carbon paste electrode covered by the poly(vinyl chloride) (PVC) membrane, which contains N,N-Dioctyl-3 α ,12 α -bis(4-trifluoroacetylbenzoyloxy)-5 β -cholan-24-amide as a carbonate ionophore. The electrode showed a near-Nernstian slope of  −27.5 mV/decade with a detection limit of 3.6 * 10 −5 mol l −1 . Generally, the detection time was 30 s. Because these electrodes are fast, convenient and low in cost, they have the potential to be mass produced and used in on-site testing as disposable sensors. Furthermore, the repeatability, reproducibility and stability have been studied to evaluate the properties of the electrodes. Measurement of the carbonate was also conducted in a human blood solution and achieved good performance. (paper)

  8. All solid supercapacitor based on polyaniline and crosslinked sulfonated poly[ether ether ketone

    International Nuclear Information System (INIS)

    Sivaraman, P.; Kushwaha, R.K.; Shashidhara, K.; Hande, V.R.; Thakur, A.P.; Samui, A.B.; Khandpekar, M.M.

    2010-01-01

    All solid supercapacitor based on polyaniline (PANI) and crosslinked sulfonated poly[ether ether ketone] (XSPEEK,) is reported in this paper. The crosslinker used for sulfonated poly[ether ether ketone] (SPEEK) is 1,4-bis(hydroxymethyl) benzene. The XSPEEK is used as both solid electrolyte and separator membrane. Supercapacitors are fabricated using various PANI/XSPEEK weight ratios. These are characterized by cyclic voltammetry and galvanostatic charge-discharge studies. The supercapacitor with PANI/XSPEEK weight ratio 1:0.5, exhibit a specific capacitance of 480 F g -1 of PANI. To the best of authors' knowledge, the value reported here is the highest for a supercapacitor based on a proton conducting solid polymer electrolyte and PANI. Detailed electrochemical impedance spectroscopy analysis is carried out. The analysis shows that the complex capacitance of the supercapacitor depends on the XSPEEK content. The time constant (t 0 ), derived from the imaginary part of complex capacitance decreases with increase in the XSPEEK content in the supercapacitor. Cycle life characteristics of the supercapacitor show a decrease in specific capacitance during initial cycles and get stabilized during later cycles.

  9. One-step spray processing of high power all-solid-state supercapacitors

    Science.gov (United States)

    Huang, Chun; Grant, Patrick S.

    2013-08-01

    Aqueous suspensions of multi-wall carbon nanotubes (MWNTs) in dilute H2SO4 were sprayed onto both sides of a Nafion membrane and dried to fabricate flexible solid-state supercapacitors. A single cell with MWNT-only electrodes had a capacitance of 57 F g-1 per electrode at 2 mV s-1 and 44 F g-1 at 150 mV s-1 but with low H+ mobility. Cells with MWNT + ionomer hybrid electrodes showed higher H+ mobility, and the electric double layer (EDL) capacitance increased to 145 F g-1 at 2 mV s-1 and 91 F g-1 at 150 mV s-1. The energy and power densities of one electrode charged to 1 V at 1 A g-1 were 12.9 Wh kg-1 and 3.3 kW kg-1 respectively. Three solid-state supercapacitor cells connected in series charged to 3 V at 1 and 2 A g-1 provided a device power density of 8.9 kW kg-1 at 1 A g-1 and 9.4 kW kg-1 at 2 A g-1, the highest for all-solid-state EDL supercapacitors.

  10. All-solid-state Al-air batteries with polymer alkaline gel electrolyte

    Science.gov (United States)

    Zhang, Zhao; Zuo, Chuncheng; Liu, Zihui; Yu, Ying; Zuo, Yuxin; Song, Yu

    2014-04-01

    Aluminum-air (Al-air) battery is one of the most promising candidates for next-generation energy storage systems because of its high capacity and energy density, and abundance. The polyacrylic acid (PAA)-based alkaline gel electrolyte is used in all-solid-state Al-air batteries instead of aqueous electrolytes to prevent leakage. The optimal gel electrolyte exhibits an ionic conductivity of 460 mS cm-1, which is close to that of aqueous electrolytes. The Al-air battery peak capacity and energy density considering only Al can reach 1166 mAh g-1-Al and 1230 mWh g-1-Al, respectively, during constant current discharge. The battery prototype also exhibits a high power density of 91.13 mW cm-2. For the battery is a laminated structure, area densities of 29.2 mAh cm-2 and 30.8 mWh cm-2 are presented to appraise the performance of the whole cell. A novel design to inhibit anodic corrosion is proposed by separating the Al anode from the gel electrolyte when not in use, thereby effectively maintaining the available capacity of the battery.

  11. One-step spray processing of high power all-solid-state supercapacitors

    Science.gov (United States)

    Huang, Chun; Grant, Patrick S.

    2013-01-01

    Aqueous suspensions of multi-wall carbon nanotubes (MWNTs) in dilute H2SO4 were sprayed onto both sides of a Nafion membrane and dried to fabricate flexible solid-state supercapacitors. A single cell with MWNT-only electrodes had a capacitance of 57 F g−1 per electrode at 2 mV s−1 and 44 F g−1 at 150 mV s−1 but with low H+ mobility. Cells with MWNT + ionomer hybrid electrodes showed higher H+ mobility, and the electric double layer (EDL) capacitance increased to 145 F g−1 at 2 mV s−1 and 91 F g−1 at 150 mV s−1. The energy and power densities of one electrode charged to 1 V at 1 A g−1 were 12.9 Wh kg−1 and 3.3 kW kg−1 respectively. Three solid-state supercapacitor cells connected in series charged to 3 V at 1 and 2 A g−1 provided a device power density of 8.9 kW kg−1 at 1 A g−1 and 9.4 kW kg−1 at 2 A g−1, the highest for all-solid-state EDL supercapacitors. PMID:23928828

  12. Highly flexible, all solid-state micro-supercapacitors from vertically aligned carbon nanotubes.

    Science.gov (United States)

    Hsia, Ben; Marschewski, Julian; Wang, Shuang; In, Jung Bin; Carraro, Carlo; Poulikakos, Dimos; Grigoropoulos, Costas P; Maboudian, Roya

    2014-02-07

    We report a highly flexible planar micro-supercapacitor with interdigitated finger electrodes of vertically aligned carbon nanotubes (VACNTs). The planar electrode structures are patterned on a thin polycarbonate substrate with a facile, maskless laser-assisted dry transfer method. Sputtered Ni is used to reduce the in-plane resistance of the VACNT electrodes. An ionogel, an ionic liquid in a semi-solid matrix, is used as an electrolyte to form a fully solid-state device. We measure a specific capacitance of 430 μF cm(-2) for a scan rate of 0.1 V s(-1) and achieve rectangular cyclic voltammograms at high scan rates of up to 100 V s(-1). Minimal change in capacitance is observed under bending. Mechanical fatigue tests with more than 1000 cycles confirm the high flexibility and durability of the novel material combination chosen for this device. Our results indicate that this scalable and facile fabrication technique shows promise for application in integrated energy storage for all solid-state flexible microdevices.

  13. Diffusion and Interface Effects during Preparation of All-Solid Microstructured Fibers

    Directory of Open Access Journals (Sweden)

    Kobelke Jens

    2014-09-01

    Full Text Available All-solid microstructured optical fibers (MOF allow the realization of very flexible optical waveguide designs. They are prepared by stacking of doped silica rods or canes in complex arrangements. Typical dopants in silica matrices are germanium and phosphorus to increase the refractive index (RI, or boron and fluorine to decrease the RI. However, the direct interface contact of stacking elements often causes interrelated chemical reactions or evaporation during thermal processing. The obtained fiber structures after the final drawing step thus tend to deviate from the targeted structure risking degrading their favored optical functionality. Dopant profiles and design parameters (e.g., the RI homogeneity of the cladding are controlled by the combination of diffusion and equilibrium conditions of evaporation reactions. We show simulation results of diffusion and thermal dissociation in germanium and fluorine doped silica rod arrangements according to the monitored geometrical disturbances in stretched canes or drawn fibers. The paper indicates geometrical limits of dopant structures in sub-µm-level depending on the dopant concentration and the thermal conditions during the drawing process. The presented results thus enable an optimized planning of the preform parameters avoiding unwanted alterations in dopant concentration profiles or in design parameters encountered during the drawing process.

  14. Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

    Directory of Open Access Journals (Sweden)

    Hongwei Deng

    2010-11-01

    Full Text Available One type of all-solid-state chloride sensor was fabricated using a MnO2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M, and the potential value remains stable with increasing immersion time. The existence of K+, Ca2+, Na+ and SO42− ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.

  15. Highly compressible three-dimensional graphene hydrogel for foldable all-solid-state supercapacitor

    Science.gov (United States)

    Liu, Xianbin; Zou, Shuai; Liu, Kaixi; Lv, Chao; Wu, Ziping; Yin, Yanhong; Liang, Tongxiang; Xie, Zailai

    2018-04-01

    The fabrication of three-dimensional (3D) graphene-based macroscopic materials with superior mechanical and electrical properties for flexible energy storage devices is still extremely challenging. Here, we report a novel 3D graphene hydrogel decorated by the biomass phytic acid (PAGH) with developed porosity and strengthen mechanical property via hydrothermal and freeze-drying methods. The phytic acid molecules are intercalated into the graphene sheets, enabling robust network structure. This induces the formation of materials with larger specific surface area, lower density and enhanced compressive strength compared with pure GH. When directly employed as an electrode, the PAGH exhibits a high specific capacitance of 248.8 F g-1 at 1 A g-1 and excellent rate performance of 67.9% as current density increasing to 20 A g-1. Furthermore, the all-solid-state supercapacitor based PAGH can deliver outstanding cycle life (86.2% after cycling 10,000 times), glorious energy density (26.5 Wh kg-1) and power density (5135.1 W kg-1). The prepared device shows stable electrochemical behaviors at random bending angles. Therefore, the present work will open a new avenue to design and fabricate new flexible and portable graphene-based electrodes for future applications in energy storage devices.

  16. Cross-Linked Solid Polymer Electrolyte for All-Solid-State Rechargeable Lithium Batteries

    International Nuclear Information System (INIS)

    Ben youcef, Hicham; Garcia-Calvo, Oihane; Lago, Nerea; Devaraj, Shanmukaraj; Armand, Michel

    2016-01-01

    Semi-interpenetrated network Solid Polymer Electrolytes (SPEs) were fabricated by UV-induced cross-linking of poly(ethyleneglycol) diacrylate (PEGDA) and divinylbenzene (DVB) within a poly(ethyleneoxide) (PEO) matrix (M v = 5 × 10 6 g mol −1 ), comprising lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI), at a molar ratio of EO:Li ∼ 30:1. The influence of the DVB content on the final SPE properties was investigated in detail. An increase of DVB concentration resulted in self-standing polymer electrolytes. The DVB cross-linker incorporation was found to decrease the crystallinity of the PEO matrix from 34% to 23%, with a decrease in the melting temperature (T m ) of the membrane from 50 °C to 34 °C. Moreover, the influence of the DVB concentration on the ionic conductivity was determined for polymer electrolytes with 0, 10, 20 and 45% DVB from room temperature (RT) to 80 °C. The resulting SPEs showed a high electrochemical stability of 4.3 V as well as practical conductivity values exceeding 10 −4 S cm −1 at 70 °C. Cycling performance of these semi-interpenetrated SPE’s have been shown with a Li metal polymer battery and all solid -state Li sulphur battery.

  17. Fabrication and performance of all-solid-state chloride sensors in synthetic concrete pore solutions.

    Science.gov (United States)

    Gao, Xiaojian; Zhang, Jian; Yang, Yingzi; Deng, Hongwei

    2010-01-01

    One type of all-solid-state chloride sensor was fabricated using a MnO(2) electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with increasing immersion time. The existence of K(+), Ca(2+), Na(+) and SO(4) (2-) ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.

  18. Design of all solid state tunable single-mode Ti: sapphire laser for nuclear industry

    International Nuclear Information System (INIS)

    Lee, J.H.; Nam, S.M.; Lee, Y.J.; Lee, J.M.; Horn, Roland E.; Wendt, Klaus

    1999-01-01

    We designed a Ti:Sapphire laser pumped by a diode laser pumped solid state laser (DPSSL). The DPSSL was intra-cavity frequency doubled and it had 20 W output power. The Ti:Sapphire laser was designed for single longitudinal mode lasing. For single mode lasing, the laser used several solid etalons. We simulated temporal evolution of the laser pulse and single pass amplification rate of the photons in each modes from rate equations. From the result, we found that single mode lasing is viable in this cavity

  19. All solid-state V2O5-based flexible hybrid fiber supercapacitors

    Science.gov (United States)

    Li, Huan; He, Jin; Cao, Xin; Kang, Liping; He, Xuexia; Xu, Hua; Shi, Feng; Jiang, Ruibin; Lei, Zhibin; Liu, Zong-Huai

    2017-12-01

    Vanadium pentoxide/single-walled carbon nanotube (V2O5-SWCNT) hybrid fibers with good electrochemical performance and flexibility are firstly prepared by using wet-spinning method. V2O5 nanobelt suspension is obtained by mixing V2O5 bulk, 30% H2O2, H2O and followed by hydrothermally treating at 190 °C for 15 h. SWCNT suspension is suspended into V2O5 nanobelt suspension under vigorous stirring, the V2O5-SWCNT homogenous suspension is obtained. It is injected into a coagulation bath composed of 5 wt % CaCl2 ethanol-water solution using syringe pump, V2O5-SWCNT hybrid fibers are prepared by washing with deionized water and drying at room temperature. Reduced graphene oxide (RGO)-SWCNT hybrid fibers are also prepared by the similar wet-spinning approach and followed by reducing GO-SWCNT hybrid fibers in an aqueous solution of hydriodic acid. All solid-state asymmetric V2O5/SWCNT//RGO/SWCNT fiber supercapacitors are assembled with V2O5-SWCNT fiber as positive electrode and RGO-SWCNT fiber as negative electrode by using PVA-H3PO4 as gel electrolyte. The assembled device not only shows maximum volumetric energy density of 1.95 mW h cm-3 at a volumetric power density of 7.5 mW cm-3, superior rate performance and cycling stability, but also exhibits remarkable flexibility to tolerate long-term and repeated bending. This work will open a new application filed of V2O5-based fibers in wearable energy storage devices.

  20. Photonic mesophases from cut rod rotators

    Energy Technology Data Exchange (ETDEWEB)

    Stelson, Angela C.; Liddell Watson, Chekesha M., E-mail: cml66@cornell.edu [Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Avendano, Carlos [Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2016-01-14

    The photonic band properties of random rotator mesophases are calculated using supercell methods applied to cut rods on a hexagonal lattice. Inspired by the thermodynamic mesophase for anisotropic building blocks, we vary the shape factor of cut fraction for the randomly oriented basis. We find large, stable bandgaps with high gap isotropy in the inverted and direct structures as a function of cut fraction, dielectric contrast, and filling fraction. Bandgap sizes up to 34.5% are maximized at high dielectric contrast for rods separated in a matrix. The bandgaps open at dielectric contrasts as low as 2.0 for the transverse magnetic polarization and 2.25 for the transverse electric polarization. Additionally, the type of scattering that promotes the bandgap is correlated with the effect of disorder on bandgap size. Slow light properties are investigated in waveguide geometry and slowdown factors up to 5 × 10{sup 4} are found.

  1. Tunable bandgaps in a deployable metamaterial

    Science.gov (United States)

    Nanda, Aditya; Karami, M. A.

    2018-06-01

    In this manuscript, we investigate deployable structures (such as solar arrays) and origami-inspired foldable structures as metamaterials capable of tunable wave manipulation. Specifically, we present a metamaterial whose bandgaps can be modulated by changing the fold angle of adjacent panels. The repeating unit cell of the structure consists of a beam (representing a panel) and a torsional spring (representing the folding mechanism). Two important cases are considered. Firstly, the fold angle (angle between adjacent beams), Ψ, is zero and only flexural waves propagate. In the second case, the fold angle is greater than zero (Ψ > 0). This causes longitudinal and transverse vibration to be coupled. FEM models are used to validate both these analyses. Increasing the fold angle was found to inflict notable changes to the wave transmission characteristics of the structure. In general, increasing the fold angles caused the bandwidth of bandgaps to increase. For the lowest four bandgaps we found bandwidth increases of 252 %, 177 %, 230 % and 163 % respectively at Ψ = 90 deg (relative to the bandwidths at Ψ = 0). In addition, non-trivial increases in bandwidth of the odd-numbered bandgaps occurs even at small fold angles-the bandwidth for the first and third bandgaps effectively double in size (increase by 100 %) at Ψ = 20 deg relative to those at Ψ = 0. This could have ramifications in the context of tunable wave manipulation and adaptive filtering. In addition, by expanding out the characteristic equation of transfer matrix for the straight structure, we prove that the upper band edge of the nth bandgap will always equal the nth simply supported natural frequency of the constituent beam. Further, we found that the ratio (EI/kt) is a pertinent parameter affecting the bandwidth of bandgaps. For low values of the ratio, effectively, no bandgap exists. For higher values of the ratio (EI/kt), we obtain a relatively large bandgap over which no waves propagate. This can

  2. Photonic bandgap structures for long-range surface plasmon polaritons

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Boltasseva, Alexandra; Søndergaard, Thomas

    2005-01-01

    Propagation of long-range surface plasmon polaritons (LR-SPPs) along periodically thickness-modulated metal stripes embedded in dielectric is studied both theoretically and experimentally for light wavelengths in the telecom range. We demonstrate that symmetric (with respect to the film surface) nm......-size thickness variations result in the pronounced band gap effect, and obtain very good agreement between measured and simulated (transmission and reflection) spectra. This effect is exploited to realize a compact wavelength add-drop filter with the bandwidth of -20 nm centered at 1550 nm. The possibilities...

  3. Low-Cost Production of Photonic Bandgap Materials Through Bubbling

    National Research Council Canada - National Science Library

    O'Brien, Daniel J; Wetzel, Eric D

    2007-01-01

    .... This report proposes a simple low-cost method for PBGM production. A device has been constructed that produces micrometer-sized, monodisperse bubbles that can be assembled into a crystal lattice by surface tension...

  4. Tunable photonic bandgap fiber based devices for optical networks

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Rottwitt, Karsten

    2005-01-01

    In future all optical networks one of the enabling technologies is tunable elements including reconfigurable routers, switches etc. Thus, the development of a technology platform that allows construction of tuning components is critical. Lately, microstructured optical fibers, filled with liquid......, for example a liquid crystal that changes optical properties when subjected to, for example, an optical or an electrical field. The utilization of these two basic properties allows design of tunable optical devices for optical networks. In this work, we focus on applications of such devices and discuss recent...... crystals, have proven to be a candidate for such a platform. Microstructured optical fibers offer unique wave-guiding properties that are strongly related to the design of the air holes in the cladding of the fiber. These wave-guiding properties may be altered by filling the air holes with a material...

  5. Electronic structure characterization and bandgap engineeringofsolar hydrogen materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jinghua

    2007-11-01

    Bandgap, band edge positions as well as the overall band structure of semiconductors are of crucial importance in photoelectrochemical and photocatalytic applications. The energy position of the band edge level can be controlled by the electronegativity of the dopants, the pH of the solution (flatband potential variation of 60 mV per pH unit), as well as by quantum confinement effects. Accordingly, band edges and bandgap can be tailored to achieve specific electronic, optical or photocatalytic properties. Synchrotron radiation with photon energy at or below 1 keV is giving new insight into such areas as condensed matter physics and extreme ultraviolet optics technology. In the soft x-ray region, the question tends to be, what are the electrons doing as they migrated between the atoms. In this paper, I will present a number of soft x-ray spectroscopic study of nanostructured 3d metal compounds Fe{sub 2}O{sub 3} and ZnO.

  6. High frequency modulation circuits based on photoconductive wide bandgap switches

    Science.gov (United States)

    Sampayan, Stephen

    2018-02-13

    Methods, systems, and devices for high voltage and/or high frequency modulation. In one aspect, an optoelectronic modulation system includes an array of two or more photoconductive switch units each including a wide bandgap photoconductive material coupled between a first electrode and a second electrode, a light source optically coupled to the WBGP material of each photoconductive switch unit via a light path, in which the light path splits into multiple light paths to optically interface with each WBGP material, such that a time delay of emitted light exists along each subsequent split light path, and in which the WBGP material conducts an electrical signal when a light signal is transmitted to the WBGP material, and an output to transmit the electrical signal conducted by each photoconductive switch unit. The time delay of the photons emitted through the light path is substantially equivalent to the time delay of the electrical signal.

  7. Design of a Polymer-Based Hollow-Core Bandgap Fiber for Low-Loss Terahertz Transmission

    DEFF Research Database (Denmark)

    Barh, Ajanta; Varshney, Ravi K.; Pal, Bishnu P.

    2016-01-01

    wavelength-scale circular air holes in a hexagonal pattern, embedded in a uniform Teflon matrix. The THz guidance in this fiber is achieved by exploiting the photonic bandgap (PBG) effect. In our low index contrast Teflon-air (1.44:1) hexagonal periodic lattice, the PBG appears only for a certain range...

  8. Electrode property of single-walled carbon nanotubes in all-solid-state lithium ion battery using polymer electrolyte

    International Nuclear Information System (INIS)

    Sakamoto, Y.; Ishii, Y.; Kawasaki, S.

    2016-01-01

    Electrode properties of single-walled carbon nanotubes (SWCNTs) in an all-solid-state lithium ion battery were investigated using poly-ethylene oxide (PEO) solid electrolyte. Charge-discharge curves of SWCNTs in the solid electrolyte cell were successfully observed. It was found that PEO electrolyte decomposes on the surface of SWCNTs.

  9. Electrode property of single-walled carbon nanotubes in all-solid-state lithium ion battery using polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Y.; Ishii, Y.; Kawasaki, S., E-mail: kawasaki.shinji@nitech.ac.jp [Nagoya Institute of Technology, Gokiso, Showa, Nagoya, Aichi (Japan)

    2016-07-06

    Electrode properties of single-walled carbon nanotubes (SWCNTs) in an all-solid-state lithium ion battery were investigated using poly-ethylene oxide (PEO) solid electrolyte. Charge-discharge curves of SWCNTs in the solid electrolyte cell were successfully observed. It was found that PEO electrolyte decomposes on the surface of SWCNTs.

  10. All-Solid-State Lithium-Sulfur Battery based on a nanoconfined LiBH 4 Electrolyte

    NARCIS (Netherlands)

    Das, Supti; Ngene, Peter; Norby, Poul; Vegge, Tejs; de Jongh, P.E.; Blanchard, Didier

    2016-01-01

    In this work we characterize all-solid-state lithium-sulfur batteries based on nano-confined LiBH4in mesoporous silica as solid electrolytes. The nano-confined LiBH4has fast ionic lithium conductivity at room temperature, 0.1 mScm-1, negligible electronic conductivity and its cationic transport

  11. Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors

    Science.gov (United States)

    Qifeng Zheng; Zhiyong Cai; Zhenqiang Ma; Shaoqin Gong

    2015-01-01

    A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4 poly (vinyl alcohol) PVA gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors...

  12. All-solid-state lithium-ion and lithium metal batteries - paving the way to large-scale production

    Science.gov (United States)

    Schnell, Joscha; Günther, Till; Knoche, Thomas; Vieider, Christoph; Köhler, Larissa; Just, Alexander; Keller, Marlou; Passerini, Stefano; Reinhart, Gunther

    2018-04-01

    Challenges and requirements for the large-scale production of all-solid-state lithium-ion and lithium metal batteries are herein evaluated via workshops with experts from renowned research institutes, material suppliers, and automotive manufacturers. Aiming to bridge the gap between materials research and industrial mass production, possible solutions for the production chains of sulfide and oxide based all-solid-state batteries from electrode fabrication to cell assembly and quality control are presented. Based on these findings, a detailed comparison of the production processes for a sulfide based all-solid-state battery with conventional lithium-ion cell production is given, showing that processes for composite electrode fabrication can be adapted with some effort, while the fabrication of the solid electrolyte separator layer and the integration of a lithium metal anode will require completely new processes. This work identifies the major steps towards mass production of all-solid-state batteries, giving insight into promising manufacturing technologies and helping stakeholders, such as machine engineering, cell producers, and original equipment manufacturers, to plan the next steps towards safer batteries with increased storage capacity.

  13. Effect of temperature on terahertz photonic and omnidirectional band gaps in one-dimensional quasi-periodic photonic crystals composed of semiconductor InSb.

    Science.gov (United States)

    Singh, Bipin K; Pandey, Praveen C

    2016-07-20

    Engineering of thermally tunable terahertz photonic and omnidirectional bandgaps has been demonstrated theoretically in one-dimensional quasi-periodic photonic crystals (PCs) containing semiconductor and dielectric materials. The considered quasi-periodic structures are taken in the form of Fibonacci, Thue-Morse, and double periodic sequences. We have shown that the photonic and omnidirectional bandgaps in the quasi-periodic structures with semiconductor constituents are strongly depend on the temperature, thickness of the constituted semiconductor and dielectric material layers, and generations of the quasi-periodic sequences. It has been found that the number of photonic bandgaps increases with layer thickness and generation of the quasi-periodic sequences. Omnidirectional bandgaps in the structures have also been obtained. Results show that the bandwidths of photonic and omnidirectional bandgaps are tunable by changing the temperature and lattice parameters of the structures. The generation of quasi-periodic sequences can also change the properties of photonic and omnidirectional bandgaps remarkably. The frequency range of the photonic and omnidirectional bandgaps can be tuned by the change of temperature and layer thickness of the considered quasi-periodic structures. This work will be useful to design tunable terahertz PC devices.

  14. Light and gas confinement in hollow-core photonic crystal fibre based photonic microcells

    DEFF Research Database (Denmark)

    Benabid, F.; Roberts, John; Couny, F.

    2009-01-01

    guides via a photonic bandgap and the other guides by virtue of an inhibited coupling between core and cladding mode constituents. For the former fibre type, we explore how the bandgap is formed using a photonic analogue of the tight-binding model and how it is related to the anti-resonant reflection...... on electromagnetically induced transparency in a rubidium filled hollow-core photonic crystal fibre, the CW-pumped hydrogen Raman laser and the generation of multi-octave spanning stimulated Raman scattering spectral combs....

  15. Analysis of phononic bandgap structures with dissipation

    DEFF Research Database (Denmark)

    Andreassen, Erik; Jensen, Jakob Søndergaard

    2013-01-01

    and longer wavelengths, we show that the two formulations produce nearly identical results in terms of propagation constant and wave decay. We use the k(ω)-formulation to compute loss factors with dissipative bandgap materials for steady-state wave propagation and create simplified diagrams that unify...... the spatial loss factor from dissipative and bandgap effects. Additionally, we demonstrate the applicability of the k(ω)-formulation for the computation of the band diagram for viscoelastic composites and compare the computed loss factors for low frequency wave propagation to existing results based on quasi...

  16. Manipulation of photons at the surface of three-dimensional photonic crystals.

    Science.gov (United States)

    Ishizaki, Kenji; Noda, Susumu

    2009-07-16

    In three-dimensional (3D) photonic crystals, refractive-index variations with a periodicity comparable to the wavelength of the light passing through the crystal give rise to so-called photonic bandgaps, which are analogous to electronic bandgaps for electrons moving in the periodic electrostatic potential of a material's crystal structure. Such 3D photonic bandgap crystals are envisioned to become fundamental building blocks for the control and manipulation of photons in optical circuits. So far, such schemes have been pursued by embedding artificial defects and light emitters inside the crystals, making use of 3D bandgap directional effects. Here we show experimentally that photons can be controlled and manipulated even at the 'surface' of 3D photonic crystals, where 3D periodicity is terminated, establishing a new and versatile route for photon manipulation. By making use of an evanescent-mode coupling technique, we demonstrate that 3D photonic crystals possess two-dimensional surface states, and we map their band structure. We show that photons can be confined and propagate through these two-dimensional surface states, and we realize their localization at arbitrary surface points by designing artificial surface-defect structures through the formation of a surface-mode gap. Surprisingly, the quality factors of the surface-defect mode are the largest reported for 3D photonic crystal nanocavities (Q up to approximately 9,000). In addition to providing a new approach for photon manipulation by photonic crystals, our findings are relevant for the generation and control of plasmon-polaritons in metals and the related surface photon physics. The absorption-free nature of the 3D photonic crystal surface may enable new sensing applications and provide routes for the realization of efficient light-matter interactions.

  17. Using Protection Layers for a 2-Photon Water Splitting Device

    DEFF Research Database (Denmark)

    Seger, Brian; Mei, Bastian Timo; Frydendal, Rasmus

    2015-01-01

    The 2-photon tandem device for photocatalytic water splitting has been theoretically shown to provide a higher efficiency than a single photon device(1). This increased efficiency can be achieved by having one material optimized to absorb high energy photons (large bandgap) and another material...... optimized to absorb low energy photons (small bandgap). To a large degree this approach has been hindered by corrosion issues. In this talk I will first discuss how our computational screening of 2,400 materials showed that very few materials can efficiently absorb light without corroding in water splitting...

  18. Low-bandgap polymer photovoltaic cells

    NARCIS (Netherlands)

    Duren, van J.K.J.; Dhanabalan, A.; Hal, van P.A.; Janssen, R.A.J.

    2001-01-01

    A-novel low-bandgap conjugated polymer (PTPTB, Eg = ~1.6 eV), consisting of alternating electron-rich N-dodecyl-2,5-bis(2'-thienyl)pyrrole (TPT) and electron-deficient 2,1,3-benzothiadiazole (B) units, as a donor material is studied together with a soluble fullerene derivative (PCBM) as acceptor to

  19. Optimal design of lossy bandgap structures

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2004-01-01

    The method of topology optimization is used to design structures for wave propagation with one lossy material component. Optimized designs for scalar elastic waves are presented for mininimum wave transmission as well as for maximum wave energy dissipation. The structures that are obtained...... are of the 1D or 2D bandgap type depending on the objective and the material parameters....

  20. Three-dimensional nitrogen and boron co-doped graphene for high-performance all-solid-state supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhong-Shuai; Chen, Long; Sun, Yi; Muellen, Klaus [Max-Planck-Institut fuer Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany); Winter, Andreas; Turchanin, Andrey [Universitaet Bielefeld, Fakultaet fuer Physik, Physik Supramolekularer Systeme und Oberflaechen, Universitaetsstr. 25D, 33615 Bielefeld (Germany); Feng, Xinliang [Max-Planck-Institut fuer Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany); School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 200240, Shanghai (China)

    2012-09-25

    A simplified prototype device of high-performance all-solid-state supercapacitors (ASSSs) based on 3D nitrogen and boron co-doped monolithic graphene aerogels (BN-GAs) is demonstrated for the first time. The resulting ASSSs show high specific capacitance, good rate capability, and enhanced energy density or power density. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Ultraflexible and tailorable all-solid-state supercapacitors using polyacrylamide-based hydrogel electrolyte with high ionic conductivity.

    Science.gov (United States)

    Li, Huili; Lv, Tian; Li, Ning; Yao, Yao; Liu, Kai; Chen, Tao

    2017-11-30

    Hydrogels with high ionic conductivity consisting of a cross-linked polymer network swollen in water are very promising to be used as an electrolyte for all-solid-state supercapacitors. However, there are rather few flexible supercapacitors using ionic conducting hydrogel electrolytes reported to date. In this work, highly flexible and ionic conducting polyacrylamide hydrogels were synthesized through a simple approach. On using the ionic hydrogels as the electrolyte, the resulting supercapacitors not only exhibited a high specific capacitance but also showed a long self-discharge time (over 10 hours to the half of original open-circuit voltage) and a low leakage current. These newly-developed all-solid-state supercapacitors can be bent, knot, and kneaded for 5000 cycles without performance decay, suggesting excellent flexibility and mechanical stability. These all-solid-state supercapacitors can also be easily tailored into strip-like supercapacitors without a short circuit, which provides an efficient approach to fabricate wearable energy storage devices.

  2. 4.5 W supercontinuum generation from 1017 to 3438 nm in an all-solid fluorotellurite fiber

    Science.gov (United States)

    Jia, Zhixu; Yao, Chuanfei; Jia, Shijie; Wang, Fang; Wang, Shunbin; Zhao, Zhipeng; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2017-06-01

    All-solid fluorotellurite fibers are fabricated by using a rod-in-tube method. The core and cladding materials are TeO2-BaF2-Y2O3 (TBY) and AlF3-based glasses, respectively. Since the refractive index (˜1.46) of AlF3-based glass is much lower than that (˜1.84) of TBY glass, the zero-dispersion-wavelength of the fabricated fiber can be tuned from 2145 to 1507 nm by varying the fiber core diameter from 50 to 3 μm. By using a 0.6 m long all-solid fluorotellurite fiber with a core diameter of ˜7 μm as the nonlinear medium and a 2 μm femtosecond fiber laser as the pump source, 4.5 W supercontinuum (SC) generation from 1017 to 3438 nm is obtained for a launched pump power of ˜10.48 W. The corresponding optical-to-optical conversion efficiency is about 42.9%. In addition, no any damage of the fluorotellurite fiber is observed during the operation of the above SC light source. Our results show that all-solid fluorotellurite fibers are promising nonlinear media for constructing high power mid-infrared SC light sources.

  3. All-solid-state flexible microsupercapacitors based on reduced graphene oxide/multi-walled carbon nanotube composite electrodes

    Science.gov (United States)

    Mao, Xiling; Xu, Jianhua; He, Xin; Yang, Wenyao; Yang, Yajie; Xu, Lu; Zhao, Yuetao; Zhou, Yujiu

    2018-03-01

    All-solid-state flexible microsupercapacitors have been intensely investigated in order to meet the rapidly growing demands for portable microelectronic devices. Herein, we demonstrate a facile, readily scalable and cost-effective laser induction process for preparing reduced graphene oxide/multi-walled carbon nanotube composite, which can be used as the interdigital electrodes in microsupercapacitors. The obtained composite exhibits high volumetric capacitance about 49.35 F cm-3, which is nearly 5 times higher than that of the pristine reduced graphene oxide film in aqueous 1.0 M H2SO4 solution (measured at a current density of 5 A cm-3 in a three-electrode testing). Additionally, an all-solid-state flexible microsupercapacitor employing these composite electrodes with PVA/H3PO4 gel electrolyte delivers high volumetric energy density of 6.47 mWh cm-3 at 10 mW cm-3 under the current density of 20 mA cm-3 as well as achieve excellent cycling stability retaining 88.6% of its initial value and outstanding coulombic efficiency after 10,000 cycles. Furthermore, the microsupercapacitors array connected in series/parallel can be easily adjusted to achieve the demands in practical applications. Therefore, this work brings a promising new candidate of prepare technologies for all-solid-state flexible microsupercapacitors as miniaturized power sources used in the portable and wearable electronics.

  4. Numerical study on characteristic of two-dimensional metal/dielectric photonic crystals

    Science.gov (United States)

    Zong, Yi-Xin; Xia, Jian-Bai; Wu, Hai-Bin

    2017-04-01

    An improved plan-wave expansion method is adopted to theoretically study the photonic band diagrams of two-dimensional (2D) metal/dielectric photonic crystals. Based on the photonic band structures, the dependence of flat bands and photonic bandgaps on two parameters (dielectric constant and filling factor) are investigated for two types of 2D metal/dielectric (M/D) photonic crystals, hole and cylinder photonic crystals. The simulation results show that band structures are affected greatly by these two parameters. Flat bands and bandgaps can be easily obtained by tuning these parameters and the bandgap width may reach to the maximum at certain parameters. It is worth noting that the hole-type photonic crystals show more bandgaps than the corresponding cylinder ones, and the frequency ranges of bandgaps also depend strongly on these parameters. Besides, the photonic crystals containing metallic medium can obtain more modulation of photonic bands, band gaps, and large effective refractive index, etc. than the dielectric/dielectric ones. According to the numerical results, the needs of optical devices for flat bands and bandgaps can be met by selecting the suitable geometry and material parameters. Project supported by the National Basic Research Program of China (Grant No. 2011CB922200) and the National Natural Science Foundation of China (Grant No. 605210010).

  5. Numerical study on characteristic of two-dimensional metal/dielectric photonic crystals

    International Nuclear Information System (INIS)

    Zong Yi-Xin; Xia Jian-Bai; Wu Hai-Bin

    2017-01-01

    An improved plan-wave expansion method is adopted to theoretically study the photonic band diagrams of two-dimensional (2D) metal/dielectric photonic crystals. Based on the photonic band structures, the dependence of flat bands and photonic bandgaps on two parameters (dielectric constant and filling factor) are investigated for two types of 2D metal/dielectric (M/D) photonic crystals, hole and cylinder photonic crystals. The simulation results show that band structures are affected greatly by these two parameters. Flat bands and bandgaps can be easily obtained by tuning these parameters and the bandgap width may reach to the maximum at certain parameters. It is worth noting that the hole-type photonic crystals show more bandgaps than the corresponding cylinder ones, and the frequency ranges of bandgaps also depend strongly on these parameters. Besides, the photonic crystals containing metallic medium can obtain more modulation of photonic bands, band gaps, and large effective refractive index, etc. than the dielectric/dielectric ones. According to the numerical results, the needs of optical devices for flat bands and bandgaps can be met by selecting the suitable geometry and material parameters. (paper)

  6. Radiation risk models for all solid cancers other than those types of cancer requiring individual assessments after a nuclear accident

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Linda [Federal Office for Radiation Protection, Department ' ' Radiation Protection and Health' ' , Oberschleissheim (Germany); University of Zurich, Medical Physics Group, Institute of Physics, Zurich (Switzerland); Zhang, Wei [Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Oxford (United Kingdom)

    2016-03-15

    In the assessment of health risks after nuclear accidents, some health consequences require special attention. For example, in their 2013 report on health risk assessment after the Fukushima nuclear accident, the World Health Organisation (WHO) panel of experts considered risks of breast cancer, thyroid cancer and leukaemia. For these specific cancer types, use was made of already published excess relative risk (ERR) and excess absolute risk (EAR) models for radiation-related cancer incidence fitted to the epidemiological data from the Japanese A-bomb Life Span Study (LSS). However, it was also considered important to assess all other types of solid cancer together and the WHO, in their above-mentioned report, stated ''No model to calculate the risk for all other solid cancer excluding breast and thyroid cancer risks is available from the LSS data''. Applying the LSS models for all solid cancers along with the models for the specific sites means that some cancers have an overlap in the risk evaluations. Thus, calculating the total solid cancer risk plus the breast cancer risk plus the thyroid cancer risk can overestimate the total risk by several per cent. Therefore, the purpose of this paper was to publish the required models for all other solid cancers, i.e. all solid cancers other than those types of cancer requiring special attention after a nuclear accident. The new models presented here have been fitted to the same LSS data set from which the risks provided by the WHO were derived. Although it is known already that the EAR and ERR effect modifications by sex are statistically significant for the outcome ''all solid cancer'', it is shown here that sex modification is not statistically significant for the outcome ''all solid cancer other than thyroid and breast cancer''. It is also shown here that the sex-averaged solid cancer risks with and without the sex modification are very similar once breast and

  7. Radiation risk models for all solid cancers other than those types of cancer requiring individual assessments after a nuclear accident

    International Nuclear Information System (INIS)

    Walsh, Linda; Zhang, Wei

    2016-01-01

    In the assessment of health risks after nuclear accidents, some health consequences require special attention. For example, in their 2013 report on health risk assessment after the Fukushima nuclear accident, the World Health Organisation (WHO) panel of experts considered risks of breast cancer, thyroid cancer and leukaemia. For these specific cancer types, use was made of already published excess relative risk (ERR) and excess absolute risk (EAR) models for radiation-related cancer incidence fitted to the epidemiological data from the Japanese A-bomb Life Span Study (LSS). However, it was also considered important to assess all other types of solid cancer together and the WHO, in their above-mentioned report, stated ''No model to calculate the risk for all other solid cancer excluding breast and thyroid cancer risks is available from the LSS data''. Applying the LSS models for all solid cancers along with the models for the specific sites means that some cancers have an overlap in the risk evaluations. Thus, calculating the total solid cancer risk plus the breast cancer risk plus the thyroid cancer risk can overestimate the total risk by several per cent. Therefore, the purpose of this paper was to publish the required models for all other solid cancers, i.e. all solid cancers other than those types of cancer requiring special attention after a nuclear accident. The new models presented here have been fitted to the same LSS data set from which the risks provided by the WHO were derived. Although it is known already that the EAR and ERR effect modifications by sex are statistically significant for the outcome ''all solid cancer'', it is shown here that sex modification is not statistically significant for the outcome ''all solid cancer other than thyroid and breast cancer''. It is also shown here that the sex-averaged solid cancer risks with and without the sex modification are very similar once breast and thyroid cancers are factored out. Some other notable model

  8. Unidirectional transmission in 1D nonlinear photonic crystal based on topological phase reversal by optical nonlinearity

    OpenAIRE

    Chong Li; Xiaoyong Hu; Hong Yang; Qihuang Gong

    2017-01-01

    We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, brin...

  9. A computational study on the energy bandgap engineering in performance enhancement of CdTe thin film solar cells

    Directory of Open Access Journals (Sweden)

    Ameen M. Ali

    Full Text Available In this study, photovoltaic properties of CdTe thin film in the configuration of n-SnO2/n-CdS/p-CdTe/p-CdTe:Te/metal have been studied by numerical simulation software named “Analysis of Microelectronic and Photonic Structure” (AMPS-1D. A modified structure for CdTe thin film solar cell has been proposed by numerical analysis with the insertion of a back contact buffer layer (CdTe:Te. This layer can serve as a barrier that will decelerate the copper diffusion in CdTe solar cell. Four estimated energy bandgap relations versus the Tellurium (Te concentrations and the (CdTe:Te layer thickness have been examined thoroughly during simulation. Correlation between energy bandgap with the CdTe thin film solar cell performance has also been established. Keywords: Numerical modelling, CdTe thin film, Solar cell, AMPS-1D, Bandgap

  10. First principle analyses of direct bandgap solar cells with absorbing substrates versus mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Alexander P. [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Kirk, Wiley P. [Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2013-11-07

    Direct bandgap InP, GaAs, CdTe, and Ga{sub 0.5}In{sub 0.5}P solar cells containing backside mirrors as well as parasitically absorbing substrates are analyzed for their limiting open circuit voltage and power conversion efficiency with comparison to record solar cells. From the principle of detailed balance, it is shown quantitatively that mirror solar cells have greater voltage and power conversion efficiency than their substrate counterparts. Next, the radiative recombination coefficient and maximum radiative lifetime of GaAs mirror and substrate solar cells are calculated and compared to the nonradiative Auger and Shockley-Read-Hall (SRH) lifetimes. Mirror solar cells have greater radiative lifetime than their substrate variants. Auger lifetime exceeds radiative lifetime for both substrate and mirror cells while SRH lifetime may be less or greater than radiative lifetime depending on trap concentration and capture cross section. Finally, the change in free energy of the photogenerated carriers is analyzed in a comparison between InP, GaAs, CdTe, and Ga{sub 0.5}In{sub 0.5}P mirror and substrate solar cells in order to characterize the relationship between solar photon quality and free energy management in solar cells with differing bandgaps. Wider bandgap visible threshold Ga{sub 0.5}In{sub 0.5}P solar cells make better use of the available change in free energy of the photogenerated charge carriers, even when normalized to the bandgap energy, than narrower bandgap near-IR threshold InP, GaAs, and CdTe solar cells.

  11. All-Solid-State Sodium-Selective Electrode with a Solid Contact of Chitosan/Prussian Blue Nanocomposite

    Directory of Open Access Journals (Sweden)

    Tanushree Ghosh

    2017-11-01

    Full Text Available Conventional ion-selective electrodes with a liquid junction have the disadvantage of potential drift. All-solid-state ion-selective electrodes with solid contact in between the metal electrode and the ion-selective membrane offer high capacitance or conductance to enhance potential stability. Solution-casted chitosan/Prussian blue nanocomposite (ChPBN was employed as the solid contact layer for an all-solid-state sodium ion-selective electrode in a potentiometric sodium ion sensor. Morphological and chemical analyses confirmed that the ChPBN is a macroporous network of chitosan that contains abundant Prussian blue nanoparticles. Situated between a screen-printed carbon electrode and a sodium-ionophore-filled polyvinylchloride ion-selective membrane, the ChPBN layer exhibited high redox capacitance and fast charge transfer capability, which significantly enhanced the performance of the sodium ion-selective electrode. A good Nernstian response with a slope of 52.4 mV/decade in the linear range from 10−4–1 M of NaCl was observed. The stability of the electrical potential of the new solid contact was tested by chronopotentiometry, and the capacitance of the electrode was 154 ± 4 µF. The response stability in terms of potential drift was excellent (1.3 µV/h for 20 h of continuous measurement. The ChPBN proved to be an efficient solid contact to enhance the potential stability of the all-solid-state ion-selective electrode.

  12. Large Bandgap Semiconductors for Solar Water Splitting

    DEFF Research Database (Denmark)

    Malizia, Mauro

    Photoelectrochemical water splitting represents an eco-friendly technology that could enable the production of hydrogen using water as reactant and solar energy as primary energy source. The exploitation of solar energy for the production of hydrogen would help modern society to reduce the reliance...... on fossil fuels as primary feedstock for hydrogen production and diminish the emission of greenhouse gases in the atmosphere, weakening the global warming phenomenon.The dissertation reports the development of GaP (gallium phosphide) photocathodes as a large bandgap semiconductor for photoelectrochemical...... water splitting devices having tandem design. The increase of the photovoltage produced by GaP under illumination was the main goal of this work. GaP has a bandgap of 2.25 eV and could in theory produce a photovoltage of approximately 1.7 V. Instead, the photovoltage produced by the semiconductor...

  13. Microporous Ni₁₁(HPO₃)₈(OH)₆ nanocrystals for high-performance flexible asymmetric all solid-state supercapacitors.

    Science.gov (United States)

    Gao, Yanping; Zhao, Junhong; Run, Zhen; Zhang, Guangqin; Pang, Huan

    2014-12-07

    Microporous nickel phosphite [Ni11(HPO3)8(OH)6] nanocrystals were prepared using a hydrothermal method, and were successfully applied as a positive electrode in a flexible all solid-state asymmetric supercapacitor. Because of the specific micro/nanostructure, the flexible solid-state asymmetric supercapacitor can achieve a maximum energy density of 0.45 mW h cm(-3), which is higher than most reported supercapacitors. More importantly, the device performance remains efficient for 10,000 cycles.

  14. All-solid-state lithium-sulfur battery based on a nanoconfined LiBH4 electrolyte

    DEFF Research Database (Denmark)

    Das, Supti; Ngene, Peter; Norby, Poul

    2016-01-01

    In this work we characterize all-solid-state lithium-sulfur batteries based on nano-confined LiBH4 in mesoporous silica as solid electrolytes. The nano-confined LiBH4 has fast ionic lithium conductivity at room temperature, 0.1 mScm-1, negligible electronic conductivity and its cationic transport...... number (t+ = 0.96), close to unity, demonstrates a purely cationic conductor. The electrolyte has an excellent stability against lithium metal. The behavior of the batteries is studied by cyclic voltammetry and repeated charge/discharge cycles in galvanostatic conditions. The batteries show very good...

  15. Origin of unusual bandgap shift and dual emission in organic-inorganic lead halide perovskites.

    Science.gov (United States)

    Dar, M Ibrahim; Jacopin, Gwénolé; Meloni, Simone; Mattoni, Alessandro; Arora, Neha; Boziki, Ariadni; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Grätzel, Michael

    2016-10-01

    Emission characteristics of metal halide perovskites play a key role in the current widespread investigations into their potential uses in optoelectronics and photonics. However, a fundamental understanding of the molecular origin of the unusual blueshift of the bandgap and dual emission in perovskites is still lacking. In this direction, we investigated the extraordinary photoluminescence behavior of three representatives of this important class of photonic materials, that is, CH 3 NH 3 PbI 3 , CH 3 NH 3 PbBr 3 , and CH(NH 2 ) 2 PbBr 3 , which emerged from our thorough studies of the effects of temperature on their bandgap and emission decay dynamics using time-integrated and time-resolved photoluminescence spectroscopy. The low-temperature (photoluminescence of CH 3 NH 3 PbI 3 and CH 3 NH 3 PbBr 3 reveals two distinct emission peaks, whereas that of CH(NH 2 ) 2 PbBr 3 shows a single emission peak. Furthermore, irrespective of perovskite composition, the bandgap exhibits an unusual blueshift by raising the temperature from 15 to 300 K. Density functional theory and classical molecular dynamics simulations allow for assigning the additional photoluminescence peak to the presence of molecularly disordered orthorhombic domains and also rationalize that the unusual blueshift of the bandgap with increasing temperature is due to the stabilization of the valence band maximum. Our findings provide new insights into the salient emission properties of perovskite materials, which define their performance in solar cells and light-emitting devices.

  16. Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

    Science.gov (United States)

    Wanlass, Mark W [Golden, CO; Mascarenhas, Angelo [Lakewood, CO

    2012-05-08

    Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

  17. Pressure-Induced Bandgap Optimization in Lead-Based Perovskites with Prolonged Carrier Lifetime and Ambient Retainability

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Kong, Lingping [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Gong, Jue [Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb IL 60115 USA; Yang, Wenge [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Mao, Ho-kwang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Hu, Qingyang [Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Liu, Zhenxian [Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Schaller, Richard D. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL 60439 USA; Zhang, Dongzhou [Hawai' i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawai' i at Manoa, Honolulu HI 96822 USA; Xu, Tao [Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb IL 60115 USA

    2016-12-05

    Bond length and bond angle exhibited by valence electrons is essential to the core of chemistry. Using lead-based organic–inorganic perovskite compounds as an exploratory platform, it is demonstrated that the modulation of valence electrons by compression can lead to discovery of new properties of known compounds. Yet, despite its unprecedented progress, further efficiency boost of lead-based organic–inorganic perovskite solar cells is hampered by their wider bandgap than the optimum value according to the Shockley–Queisser limit. By modulating the valence electron wavefunction with modest hydraulic pressure up to 2.1 GPa, the optimized bandgap for single-junction solar cells in lead-based perovskites, for the first time, is achieved by narrowing the bandgap of formamidinium lead triiodide (HC(NH2)2PbI3) from 1.489 to 1.337 eV. Strikingly, such bandgap narrowing is partially retained after the release of pressure to ambient, and the bandgap narrowing is also accompanied with double-prolonged carrier lifetime. With First-principles simulation, this work opens a new dimension in basic chemical understanding of structural photonics and electronics and paves an alternative pathway toward better photovoltaic materials-by-design.

  18. Pressure-Induced Bandgap Optimization in Lead-Based Perovskites with Prolonged Carrier Lifetime and Ambient Retainability

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Kong, Lingping [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Gong, Jue [Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb IL 60115 USA; Yang, Wenge [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Mao, Ho-kwang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 China; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Hu, Qingyang [Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Liu, Zhenxian [Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015 USA; Schaller, Richard D. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL 60439 USA; Zhang, Dongzhou [Hawai' i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawai' i at Manoa, Honolulu HI 96822 USA; Xu, Tao [Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb IL 60115 USA

    2016-12-05

    Bond length and bond angle exhibited by valence electrons is essential to the core of chemistry. Using lead-based organic–inorganic perovskite compounds as an exploratory platform, it is demonstrated that the modulation of valence electrons by compression can lead to discovery of new properties of known compounds. Yet, despite its unprecedented progress, further efficiency boost of lead-based organic–inorganic perovskite solar cells is hampered by their wider bandgap than the optimum value according to the Shockley–Queisser limit. By modulating the valence electron wavefunction with modest hydraulic pressure up to 2.1 GPa, the optimized bandgap for single-junction solar cells in lead-based perovskites, for the first time, is achieved by narrowing the bandgap of formamidinium lead triiodide (HC(NH2)2PbI3) from 1.489 to 1.337 eV. Strikingly, such bandgap narrowing is partially retained after the release of pressure to ambient, and the bandgap narrowing is also accompanied with double-prolonged carrier lifetime. With First-principles simulation, this work opens a new dimension in basic chemical understanding of structural photonics and electronics and paves an alternative pathway toward better photovoltaic materials-by-design.

  19. Analysis of structural and thermal stability in the positive electrode for sulfide-based all-solid-state lithium batteries

    Science.gov (United States)

    Tsukasaki, Hirofumi; Otoyama, Misae; Mori, Yota; Mori, Shigeo; Morimoto, Hideyuki; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2017-11-01

    Sulfide-based all-solid-state batteries using a non-flammable inorganic solid electrolyte are promising candidates as a next-generation power source owing to their safety and excellent charge-discharge cycle characteristics. In this study, we thus focus on the positive electrode and investigated structural stabilities of the interface between the positive electrode active material LiNi1/3Mn1/3Co1/3O2 (NMC) and the 75Li2S·25P2S5 (LPS) glass electrolyte after charge-discharge cycles via transmission electron microscopy (TEM). To evaluate the thermal stability of the fabricated all-solid-state cell, in-situ TEM observations for the positive electrode during heating are conducted. As a result, structural and morphological changes are detected in the LPS glasses. Thus, exothermal reaction present in the NMC-LPS composite positive electrode after the initial charging is attributable to the crystallization of LPS glasses. On the basis of a comparison with crystallization behavior in single LPS glasses, the origin of exothermal reaction in the NMC-LPS composites is discussed.

  20. Fabrication of amorphous Si and C anode films via co-sputtering for an all-solid-state battery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.S. [Department of Materials Science and Engineering, Yonsei University Shinchondong, 262 Seongsanno, Seodaemoongu, Seoul 120-749 (Korea, Republic of); Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Lee, S.H. [Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Woo, S.P. [Department of Materials Science and Engineering, Yonsei University Shinchondong, 262 Seongsanno, Seodaemoongu, Seoul 120-749 (Korea, Republic of); Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Kim, H.S. [Department of Mechanical Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of); Yoon, Y.S., E-mail: benedicto@gachon.ac.kr [Department of Environment and Energy Engineering, Gachon University, Seongnamdaero 1342, 461-710 Gyeonggi-do (Korea, Republic of)

    2014-08-01

    In this study, a combination of silicon and carbon as the anode material for an all-solid-state battery has been investigated to overcome their individual deficiencies. The capacity of silicon thin films with an input power of 60 W shows dramatic failure after 38 cycles due to serious volume expansion. In contrast, C thin films at 60 W show high stability of cyclic performance and capacity retention. The amorphous silicon and carbon composite reduced the volume expansion of silicon during long term cycles and enhanced the low specific capacity of the carbon. This resistance of the volume expansion might be expected from the cushion effect caused by the carbon, which was confirmed by scanning electron microscope images after a 100 cycle test. These results indicate that amorphous silicon and carbon composite thin films have a high possibility as the stable anode material for an all-solid-state battery. - Highlights: • Amorphous Si/C nanocomposite thin films have been prepared by co-sputtering. • Carbon can act as a cushion effect to prevent volume expansion of Si. • Amorphous Si/C nanocomposite thin films show structure stability at 100 cycles. • Capacity of the amorphous Si/C nanocomposite thin films was enhanced considerably.

  1. All solid-state polymer electrolytes prepared from a hyper-branched graft polymer using atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Higa, Mitsuru; Fujino, Yukiko; Koumoto, Taihei; Kitani, Ryousuke; Egashira, Satsuki

    2005-01-01

    We propose an all solid-state (liquid free) polymer electrolyte (SPE) prepared from a hyper-branched graft copolymer. The graft copolymer consisting of a poly(methyl methacrylate) main chain and poly(ethylene glycol) methyl ether methacrylate side chains was synthesized by atom transfer radical polymerization changing the average chain distance between side chains, side chain length and branched chain length of the proposed structure of the graft copolymer. The ionic conductivity of the SPEs increases with increasing the side chain length, branched chain length and/or average distance between the side chains. The ionic conductivity of the SPE prepared from POEM 9 whose POEM content = 51 wt% shows 2 x 10 -5 S/cm at 30 deg. C. The tensile strength of the SPEs decreases with increases the side chain length, branched chain length and/or average distance between the side chains. These results indicate that a SPE prepared from the hyper-branched graft copolymer has potential to be applied to an all-solid polymer electrolyte

  2. Nitrogen doped carbon derived from polyimide/multiwall carbon nanotube composites for high performance flexible all-solid-state supercapacitors

    Science.gov (United States)

    Kim, Dae Kyom; Kim, Nam Dong; Park, Seung-Keun; Seong, Kwang-dong; Hwang, Minsik; You, Nam-Ho; Piao, Yuanzhe

    2018-03-01

    Flexible all-solid-state supercapacitors are desirable as potential energy storage systems for wearable technologies. Herein, we synthesize aminophenyl multiwall carbon nanotube (AP-MWCNT) grafted polyimide precursor by in situ polymerization method as a nitrogen-doped carbon precursor. Flexible supercapacitor electrodes are fabricated via a coating of carbon precursor on carbon cloth surface and carbonization at high temperature directly. The as-obtained electrodes, which can be directly used without any binders or additives, can deliver a high specific capacitance of 333.4 F g-1 at 1 A g-1 (based on active material mass) and excellent cycle stability with 103% capacitance retention after 10,000 cycles in a three-electrode system. The flexible all-solid-state supercapacitor device exhibits a high volumetric capacitance of 3.88 F cm-3 at a current density of 0.02 mA cm-3. And also the device can deliver a maximum volumetric energy density of 0.50 mWh cm-3 and presents good cycling stability with 85.3% capacitance retention after 10,000 cycles. This device cell can not only show extraordinary mechanical flexibilities allowing folding, twisting, and rolling but also demonstrate remarkable stable electrochemical performances under their forms. This work provides a novel approach to obtain carbon textile-based flexible supercapacitors with high electrochemical performance and mechanical flexibility.

  3. Atomic layer deposition of lithium phosphates as solid-state electrolytes for all-solid-state microbatteries

    International Nuclear Information System (INIS)

    Wang, Biqiong; Liu, Jian; Sun, Qian; Li, Ruying; Sun, Xueliang; Sham, Tsun-Kong

    2014-01-01

    Atomic layer deposition (ALD) has been shown as a powerful technique to build three-dimensional (3D) all-solid-state microbattery, because of its unique advantages in fabricating uniform and pinhole-free thin films in 3D structures. The development of solid-state electrolyte by ALD is a crucial step to achieve the fabrication of 3D all-solid-state microbattery by ALD. In this work, lithium phosphate solid-state electrolytes were grown by ALD at four different temperatures (250, 275, 300, and 325 °C) using two precursors (lithium tert-butoxide and trimethylphosphate). A linear dependence of film thickness on ALD cycle number was observed and uniform growth was achieved at all four temperatures. The growth rate was 0.57, 0.66, 0.69, and 0.72 Å/cycle at deposition temperatures of 250, 275, 300, and 325 °C, respectively. Furthermore, x-ray photoelectron spectroscopy confirmed the compositions and chemical structures of lithium phosphates deposited by ALD. Moreover, the lithium phosphate thin films deposited at 300 °C presented the highest ionic conductivity of 1.73 × 10 −8 S cm −1 at 323 K with ∼0.51 eV activation energy based on the electrochemical impedance spectroscopy. The ionic conductivity was calculated to be 3.3 × 10 −8 S cm −1 at 26 °C (299 K). (paper)

  4. The improvement of all-solid-state electrochromic devices fabricated with the reactive sputter and cathodic arc technology

    Directory of Open Access Journals (Sweden)

    Min-Chuan Wang

    2016-11-01

    Full Text Available The all-solid-state electrochromic device (ECD with the one substrate structure fabricated by the reactive dc magnetron sputtering (DCMS and cathodic vacuum arc plasma (CVAP technology has been developed for smart electrochromic (EC glass application. The EC layer and ion conductor layer were deposited by reactive DCMS and CVAP technology, respectively. The ion conductor layer Ta2O5 deposited by the CVAP technology has provided the better porous material structure for ion transportation and showed 1.76 times ion conductivity than devices with all sputtering process. At the same time, the EC layer WO3 and NiO deposited by the reactive DCMS have also provided the high quality and uniform characteristic to overcome the surface roughness effect of the CVAP ion conductor layer in multilayer device structure. The all-solid-state ECD with the CVAP ion conductor layer has demonstrated a maximum transmittance variation (ΔT of 55% at 550nm and a faster-switching speed. Furthermore, the lower equipment cost and higher deposition rate could be achieved by the application of CVAP technology.

  5. Three-dimensional photonic crystals created by single-step multi-directional plasma etching.

    Science.gov (United States)

    Suzuki, Katsuyoshi; Kitano, Keisuke; Ishizaki, Kenji; Noda, Susumu

    2014-07-14

    We fabricate 3D photonic nanostructures by simultaneous multi-directional plasma etching. This simple and flexible method is enabled by controlling the ion-sheath in reactive-ion-etching equipment. We realize 3D photonic crystals on single-crystalline silicon wafers and show high reflectance (>95%) and low transmittance (photonic bandgap. Moreover, our method simply demonstrates Si-based 3D photonic crystals that show the photonic bandgap effect in a shorter wavelength range around 0.6 μm, where further fine structures are required.

  6. Ab initio study of the bandgap engineering of Al1−xGaxN for optoelectronic applications

    KAUST Repository

    Amin, B.; Ahmad, Iftikhar; Maqbool, M.; Goumri-Said, S.; Ahmad, R.

    2011-01-01

    A theoretical study of Al1−xGaxN, based on the full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap,optical properties, and nonlinear behavior of the compound with the change in the Ga concentration. It is found that the bandgap decreases with the increase in Ga. A maximum value of 5.50 eV is determined for the bandgap of pure AlN, which reaches a minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in the bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for higher energy photons, larger than 14 eV. The group velocity of these photons is larger than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to nonlinear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak values of the absorption coefficient and reflectivity shift toward lower energy in the ultraviolet (UV) spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.

  7. Ab initio study of the bandgap engineering of Al1−xGaxN for optoelectronic applications

    KAUST Repository

    Amin, B.

    2011-01-19

    A theoretical study of Al1−xGaxN, based on the full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap,optical properties, and nonlinear behavior of the compound with the change in the Ga concentration. It is found that the bandgap decreases with the increase in Ga. A maximum value of 5.50 eV is determined for the bandgap of pure AlN, which reaches a minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in the bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for higher energy photons, larger than 14 eV. The group velocity of these photons is larger than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to nonlinear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak values of the absorption coefficient and reflectivity shift toward lower energy in the ultraviolet (UV) spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.

  8. Silicon nanostructures for photonics and photovoltaics

    NARCIS (Netherlands)

    Priolo, F.; Gregorkiewicz, T.; Galli, M.; Krauss, T.F.

    2014-01-01

    Silicon has long been established as the material of choice for the microelectronics industry. This is not yet true in photonics, where the limited degrees of freedom in material design combined with the indirect bandgap are a major constraint. Recent developments, especially those enabled by

  9. Q-switched all-solid-state lasers and application in processing of thin-film solar cell

    Science.gov (United States)

    Liu, Liangqing; Wang, Feng

    2009-08-01

    Societal pressure to renewable clean energy is increasing which is expected to be used as part of an overall strategy to address global warming and oil crisis. Photovoltaic energy conversion devices are on a rapidly accelerating growth path driven by government, of which the costs and prices lower continuously. The next generation thin-film devices are considered to be more efficiency and greatly reduced silicon consumption, resulting in dramatically lower per unit fabrication costs. A key aspect of these devices is patterning large panels to create a monolithic array of series-interconnected cells to form a low current, high voltage module. This patterning is accomplished in three critical scribing processes called P1, P2, and P3. All-solid-state Q-switched lasers are the technology of choice for these processes, due to their advantages of compact configuration, high peak-value power, high repeat rate, excellent beam quality and stability, delivering the desired combination of high throughput and narrow, clean scribes. The end pumped all-solid-state lasers could achieve 1064nm IR resources with pulse width of nanoseconds adopting acoustic-optics Q-switch, shorter than 20ns. The repeat rate is up to 100kHz and the beam quality is close to diffraction limit. Based on this, 532nm green lasers, 355nm UV lasers and 266nm DUV lasers could be carried out through nonlinear frequency conversion. Different wave length lasers are chose to process selective materials. For example, 8-15 W IR lasers are used to scribe the TCO film (P1); 1-5 W green lasers are suitable for scribing the active semiconductor layers (P2) and the back contact layers (P3). Our company, Wuhan Lingyun Photo-electronic System Co. Ltd, has developed 20W IR and 5W green end-pumped Q-switched all-solid-state lasers for thin-film solar industry. Operating in high repeat rates, the speed of processing is up to 2.0 m/s.

  10. Electrochemical performance of all-solid-state lithium secondary batteries with Li-Ni-Co-Mn oxide positive electrodes

    International Nuclear Information System (INIS)

    Kitaura, Hirokazu; Hayashi, Akitoshi; Tadanaga, Kiyoharu; Tatsumisago, Masahiro

    2010-01-01

    LiNi 1/3 Co 1/3 Mn 1/3 O 2 was applied as a promising material to the all-solid-state lithium cells using the 80Li 2 S.19P 2 S 5 .1P 2 O 5 (mol%) solid electrolyte. The cell showed the first discharge capacity of 115 mAh g -1 at the current density of 0.064 mA cm -2 and retained the reversible capacity of 110 mAh g -1 after 10 cycles. The interfacial resistance was observed in the impedance spectrum of the all-solid-state cell charged to 4.4 V (vs. Li) and the transition metal elements were detected on the solid electrolyte in the vicinity of LiNi 1/3 Co 1/3 Mn 1/3 O 2 by the TEM observations with EDX analyses. The electrochemical performance was improved by the coating of LiNi 1/3 Co 1/3 Mn 1/3 O 2 particles with Li 4 Ti 5 O 12 film. The interfacial resistance was decreased and the discharge capacity was increased from 63 to 83 mAh g -1 at 1.3 mA cm -2 by the coating. The electrochemical performance of LiNi 1/3 Co 1/3 Mn 1/3 O 2 was compared with that of LiCoO 2 , LiMn 2 O 4 and LiNiO 2 in the all-solid-state cells. The rate capability of LiNi 1/3 Co 1/3 Mn 1/3 O 2 was lower than that of LiCoO 2 . However, the reversible capacity of LiNi 1/3 Co 1/3 Mn 1/3 O 2 at 0.064 mA cm -2 was larger than that of LiCoO 2 , LiMn 2 O 4 and LiNiO 2 .

  11. Photonic quasicrystals for application in WDM systems

    DEFF Research Database (Denmark)

    Romero-Vivas, J.; Chigrin, D. N.; Lavrinenko, Andrei

    2005-01-01

    Photonic quasicrystals can possess an isotropic (complete) photonic bandgap even in the case of low refractive indices of the constitutive materials, which makes them atrractive optical materials with important technological applications. In this work, several aspects related to the design...... of waveguides and cavities using the two-dimensional (2D) octagonal quasiperiodic lattice are investigated numerically. As an example, the integration of waveguides and a resonating cavity to design an add/drop filer for wavelength division multiplexing applications is brieflydescribed....

  12. The LiBH4-LiI Solid Solution as an Electrolyte in an All-Solid-State Battery

    DEFF Research Database (Denmark)

    Sveinbjörnsson, Dadi Þorsteinn; Christiansen, Ane Sælland; Viskinde, Rasmus

    2014-01-01

    The charge and discharge performance of an all-solid-state lithium battery with the LiBH4-LiI solid solution as an electrolyte is reported. Lithium titanate (Li4Ti5O12) was used as the positive electrode and lithium metal as the negative electrode. The performance of the all-solid-state cell...

  13. Frequency conversion through spontaneous degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin

    2014-01-01

    Frequency conversion through spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers. Different FWM processes are observed, phasematching between fiber modes of orthogonal polarization, intermodal phasematching across bandgaps, and intramodal...

  14. Disorder-induced modification of the transmission of light through two-dimensional photonic crystals

    International Nuclear Information System (INIS)

    Beggs, D M; Kaliteevski, M A; Abram, R A; Cassagne, D; Albert, J P

    2005-01-01

    Disordered two-dimensional photonic crystals with a complete photonic band-gap have been investigated. Transmission and reflection spectra have been modelled for both ballistic and scattered light. The density of states and electromagnetic field profiles of disorder-induced localized states have also been calculated, for various levels of disorder. It is found that there is a threshold-like behaviour in the amount of disorder. Below the threshold, it is seen that there is a vanishing probability of disorder-induced localized states being introduced into the centre of the photonic band-gap, but that edge-states narrow the band-gap. Above the threshold, there is a non-zero probability of disorder-induced localized states throughout the photonic band-gap, and the modification of the transmission and reflection spectra due to disorder rapidly increases with increasing disorder

  15. All-solid-state flexible supercapacitors fabricated with bacterial nanocellulose papers, carbon nanotubes, and triblock-copolymer ion gels.

    Science.gov (United States)

    Kang, Yu Jin; Chun, Sang-Jin; Lee, Sung-Suk; Kim, Bo-Yeong; Kim, Jung Hyeun; Chung, Haegeun; Lee, Sun-Young; Kim, Woong

    2012-07-24

    We demonstrate all-solid-state flexible supercapacitors with high physical flexibility, desirable electrochemical properties, and excellent mechanical integrity, which were realized by rationally exploiting unique properties of bacterial nanocellulose, carbon nanotubes, and ionic liquid based polymer gel electrolytes. This deliberate choice and design of main components led to excellent supercapacitor performance such as high tolerance against bending cycles and high capacitance retention over charge/discharge cycles. More specifically, the performance of our supercapacitors was highly retained through 200 bending cycles to a radius of 3 mm. In addition, the supercapacitors showed excellent cyclability with C(sp) (~20 mF/cm(2)) reduction of only <0.5% over 5000 charge/discharge cycles at the current density of 10 A/g. Our demonstration could be an important basis for material design and development of flexible supercapacitors.

  16. All-solid-state flexible supercapacitors based on highly dispersed polypyrrole nanowire and reduced graphene oxide composites.

    Science.gov (United States)

    Yu, Chenfei; Ma, Peipei; Zhou, Xi; Wang, Anqi; Qian, Tao; Wu, Shishan; Chen, Qiang

    2014-10-22

    Highly dispersed polypyrrole nanowires are decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composites exhibit high dispersibility, large effective surface area, and high electric conductivity. All-solid-state flexible supercapacitors are assembled based on the prepared composites, which show excellent electrochemical performances with a specific capacitance of 434.7 F g(-1) at a current density of 1 A g(-1). The as-fabricated supercapacitor also exhibits excellent cycling stability (88.1% capacitance retention after 5000 cycles) and exceptional mechanical flexibility. In addition, outstanding power and energy densities were obtained, demonstrating the significant potential of prepared material for flexible and portable energy storage devices.

  17. Opto-electronic scanning of colour pictures with P/sup 2/CCC-all solid state line sensors

    Energy Technology Data Exchange (ETDEWEB)

    Damann, H; Rabe, G; Zinke, M; Herrmann, M; Imjela, R; Laasch, I; Mueller, J; Neumann, K; Tauchen, G; Woelber, J

    1982-04-01

    A new one-chip all solid state line sensor (P/sup 2/CCD-Tricoli) has been realized as a basis for the opto-electronic scanning of colour pictures. The three photosensitive lines for the colour components red, green and blue contain each 652 photo elements. They are arranged in parallel on one silicon crystal, with distances of some 100 ..mu..m. The line sensor is supplied with an extra designed driving circuitry and a signal processing. For colour splitting a colour separating digital phase grating has been developed which generates the three colour components in its three central diffraction orders. Using all the development components ('Tricoli'-line-sensor, electronic circuitry, colour separation grating) a model of a slide scanner has been built up, which succesfully demonstrates the feasibility of the proposed colour scanning system.

  18. All-Solid-State Textile Batteries Made from Nano-Emulsion Conducting Polymer Inks for Wearable Electronics

    Directory of Open Access Journals (Sweden)

    Tapani Ryhänen

    2012-08-01

    Full Text Available A rollable and all-solid-state textile lithium battery based on fabric matrix and polymer electrolyte that allows flexibility and fast-charging capability is reported. When immerged into poly(3,4-ethylenedioxythiophene (PEDOT nano-emulsion inks, an insulating fabric is converted into a conductive battery electrode for a fully solid state lithium battery with the highest specific energy capacity of 68 mAh/g. This is superior to most of the solid-state conducting polymer primary and/or secondary batteries reported. The bending radius of such a textile battery is less than 1.5 mm while lightening up an LED. This new material combination and inherent flexibility is well suited to provide an energy source for future wearable and woven electronics.

  19. An All-Solid-State High Repetiton Rate Titanium:Sapphire Laser System For Resonance Ionization Laser Ion Sources

    Science.gov (United States)

    Mattolat, C.; Rothe, S.; Schwellnus, F.; Gottwald, T.; Raeder, S.; Wendt, K.

    2009-03-01

    On-line production facilities for radioactive isotopes nowadays heavily rely on resonance ionization laser ion sources due to their demonstrated unsurpassed efficiency and elemental selectivity. Powerful high repetition rate tunable pulsed dye or Ti:sapphire lasers can be used for this purpose. To counteract limitations of short pulse pump lasers, as needed for dye laser pumping, i.e. copper vapor lasers, which include high maintenance and nevertheless often only imperfect reliability, an all-solid-state Nd:YAG pumped Ti:sapphire laser system has been constructed. This could complement or even replace dye laser systems, eliminating their disadvantages but on the other hand introduce shortcomings on the side of the available wavelength range. Pros and cons of these developments will be discussed.

  20. Flexible all-solid-state high-performance supercapacitor based on electrochemically synthesized carbon quantum dots/polypyrrole composite electrode

    International Nuclear Information System (INIS)

    Jian, Xuan; Yang, Hui-min; Li, Jia-gang; Zhang, Er-hui; Cao, Le-le; Liang, Zhen-hai

    2017-01-01

    Highlights: • Porous nanostructure carbon quantum dots/polypyrrole composite film was successfully synthesized by direct electrochemical method. • A flexible all-solid-state supercapacitor device was fabricated using the carbon quantum dots/polypyrrole composite electrode. • The flexible supercapacitor exhibits high specific capacitance, excellent reliability and long cycling life. - Abstract: Recently, carbon quantum dots (CQDs) as a new zero-dimensional carbon nanomaterial have become a focus in electrochemical energy storage. In this paper, flexible all-solid-state supercapacitors (ASSSs) were electrochemically synthesized by on-step co-deposition of appropriate amounts of pyrrole monomer and CQDs in aqueous solution. The different electrodeposition time plays an important role in controlling morphologies of stainless steel wire meshes (SSWM)-supported CQDs/PPy composite film. The morphologies and compositions of the obtained CQDs/PPy composite electrodes were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Furthermore, a novel flexible ASSS device was fabricated using CQDs/PPy composite as the electrode and separated by polyvinyl alcohol/LiCl gel electrolyte. Benefiting from superior electrochemical properties of CQDs and PPy, the as-prepared CQDs/PPy composite ASSSs exhibit outstanding electrochemical performance with the areal capacitance 315 mF cm −2 (corresponding to specific capacitance of 308 F g −1 ) at a current density of 0.2 mA cm −2 and long cycle life with 85.7% capacitance retention after 2 000 cycles.

  1. Flexible Black-Phosphorus Nanoflake/Carbon Nanotube Composite Paper for High-Performance All-Solid-State Supercapacitors.

    Science.gov (United States)

    Yang, Bingchao; Hao, Chunxue; Wen, Fusheng; Wang, Bochong; Mu, Congpu; Xiang, Jianyong; Li, Lei; Xu, Bo; Zhao, Zhisheng; Liu, Zhongyuan; Tian, Yongjun

    2017-12-27

    We proposed a simple route for fabrication of the flexible BP nanoflake/carbon nanotube (CNT) composite paper as flexible electrodes in all-solid-state supercapacitors. The highly conductive CNTs not only play a role as active materials but also increase conductivity of the hybrid electrode, enhance electrolyte shuttling and prevent the restacking between BP nanoflakes. The fabricated flexible all-solid-state supercapacitor (ASSP) device at the mass proportion of BP/CNTs 1:4 was found to deliver the highest volumetric capacitance of up to 41.1 F/cm 3 at 0.005 V/s, superior to the ASSP based on the bare graphene or BP. The BP/CNTs (1:4) device delivers a rapid charging/discharging up to 500 V/s, which exhibits the characteristic of a high power density of 821.62 W/cm 3 , while having outstanding mechanical flexibility and high cycling stability over 10 000 cycles (91.5% capacitance retained). Moreover the BP/CNTs (1:4) ASSP device still retains large volumetric capacitance (35.7 F/cm 3 at the scan rate of 0.005 V/s) even after 11 months. In addition, the ASSP of BP/CNTs (1:4) exhibits high energy density of 5.71 mWh/cm 3 and high power density of 821.62 W/cm 3 . As indicated in our work, the strategy of assembling stacked-layer composites films will open up novel possibility for realizing BP and CNTs in new-concept thin-film energy storage devices.

  2. High-performance flexible all-solid-state supercapacitors based on densely-packed graphene/polypyrrole nanoparticle papers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chao; Zhang, Liling [Key Laboratory for Thin Film and Microfabrication Technology of the Ministry of Education, School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Dong Chuan Road No. 800, Shanghai, 200240 (China); Hu, Nantao, E-mail: hunantao@sjtu.edu.cn [Key Laboratory for Thin Film and Microfabrication Technology of the Ministry of Education, School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Dong Chuan Road No. 800, Shanghai, 200240 (China); Yang, Zhi; Wei, Hao [Key Laboratory for Thin Film and Microfabrication Technology of the Ministry of Education, School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Dong Chuan Road No. 800, Shanghai, 200240 (China); Wang, Yanyan, E-mail: yywang@suda.edu.cn [College of Physics, Optoelectronics and Energy, Soochow University, Suzhou, 215006 (China); Zhang, Yafei, E-mail: yfzhang@sjtu.edu.cn [Key Laboratory for Thin Film and Microfabrication Technology of the Ministry of Education, School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Dong Chuan Road No. 800, Shanghai, 200240 (China)

    2016-11-30

    Highlights: • The addition of methyl orange can affect the size of polypyrrole nanoparticles. • The flexible hybrid paper has a highly-interconnected sandwich framework. • The hybrid paper shows a high areal and volumetric specific capacitance. • Flexible all-solid-state supercapacitor exhibits excellent capacitive performances. - Abstract: Graphene-based all-solid-state supercapacitors (ASSSCs) have received increasing attention. It’s a great challenge to fabricate high-performance flexible solid-state supercapacitors with high areal and volumetric energy storage capability, superior electron and ion conductivity, robust mechanical flexibility, as well as long term stability. Herein, we report a facile method to fabricate flexible ASSSCs based on densely-packed reduced graphene oxide (rGO)/polypyrrole nanoparticle (PPy NP) hybrid papers with a sandwich framework, which consists of well-separated and continuously-aligned rGO sheets. The incorporation of PPy NPs not only provides pseudocapacitance but also facilitates the infiltration of gel electrolyte. The assembled ASSSCs possess maximum areal and volumetric specific capacitances of 477 mF/cm{sup 2} and 94.9 F/cm{sup 3} at 0.5 mA/cm{sup 2}. They also exhibit little capacitance deviation under different bending states, excellent cycling stability, small leakage current and low self-discharge characteristics. Additionally, the maximum areal and volumetric energy densities of 132.5 μWh/cm{sup 2} and 26.4 mWh/cm{sup 3} are achieved, which indicate that this hybrid paper is a promising candidate for high-performance flexible energy storage devices.

  3. Bandgap Optimization of Perovskite Semiconductors for Photovoltaic Applications.

    Science.gov (United States)

    Xiao, Zewen; Zhou, Yuanyuan; Hosono, Hideo; Kamiya, Toshio; Padture, Nitin P

    2018-02-16

    The bandgap is the most important physical property that determines the potential of semiconductors for photovoltaic (PV) applications. This Minireview discusses the parameters affecting the bandgap of perovskite semiconductors that are being widely studied for PV applications, and the recent progress in the optimization of the bandgaps of these materials. Perspectives are also provided for guiding future research in this area. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Nonlinear spatial mode imaging of hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Laurila, Marko

    2013-01-01

    Degenerate spontaneous four wave mixing is studied for the rst time in a large mode area hybrid photonic crystal ber, where light con nement is achieved by combined index- and bandgap guiding. Four wave mixing products are generated on the edges of the bandgaps, which is veri ed by numerical and ...... and experimental results. Since the core mode is in resonance with cladding modes near the bandedges an unconventional measurement technique is used, in this work named nonlinear spatial mode imaging....

  5. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  6. Photon-photon interactions

    International Nuclear Information System (INIS)

    Gilman, F.J.

    1980-01-01

    A brief summary of the present status of photon-photon interactions is presented. Stress is placed on the use of two-photon collisions to test present ideas on the quark constituents of hadrons and on the theory of strong interactions

  7. Contact and Bandgap Engineering in Two Dimensional Crystal

    Science.gov (United States)

    Chu, Tao

    At the heart of semiconductor research, bandgap is one of the key parameters for materials and determine their applications in modern technologies. For traditional bulk semiconductors, the bandgap is determined by the chemical composition and specific arrangement of the crystal lattices, and usually invariant during the device operation. Nevertheless, it is highly desirable for many optoelectronic and electronic applications to have materials with continuously tunable bandgap available. In the past decade, 2D layered materials including graphene and transition metal dichalcogenides (TMDs) have sparked interest in the scientific community, owing to their unique material properties and tremendous potential in various applications. Among many newly discovered properties that are non-existent in bulk materials, the strong in-plane bonding and weak van der Waals inter-planar interaction in these 2D layered structures leads to a widely tunable bandgap by electric field. This provides an extra knob to engineer the fundamental material properties and open a new design space for novel device operation. This thesis focuses on this field controlled dynamic bandgap and can be divided into three parts: (1) bilayer graphene is the first known 2D crystal with a bandgap can be continuously tuned by electric field. However, the electrical transport bandgaps is much smaller than both theoretical predictions and extracted bandgaps from optical measurements. In the first part of the thesis, the limiting factors of preventing achieving a large transport bandgap in bilayer graphene are investigated and different strategies to achieve a large transport bandgap are discussed, including the vertically scaling of gate oxide and patterning channel into ribbon structure. With a record large transport bandgap of ~200meV, a dual-gated semiconducting bilayer graphene P/N junction with extremely scaled gap of 20nm in-between is fabricated. A tunable local maxima feature, associated with 1D v

  8. Reconfigurable topological photonic crystal

    Science.gov (United States)

    Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.

    2018-02-01

    Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.

  9. A New All-Solid-State Hyperbranched Star Polymer Electrolyte for Lithium Ion Batteries: Synthesis and Electrochemical Properties

    International Nuclear Information System (INIS)

    Wang, Ailian; Xu, Hao; Zhou, Qian; Liu, Xu; Li, Zhengyao; Gao, Rui; Wu, Na; Guo, Yuguo; Li, Huayi; Zhang, Liaoyun

    2016-01-01

    Highlights: • A new hyperbranched multi-arm star polymer was successfully synthesized. • The star polymer electrolyte has good thermal stability and forming-film property. • The ion conductivity electrolyte can reach 8.3 × 10"−"5 S cm"−"1 at room temperature. • The star polymer electrolyte has wide electrochemical windows of 4.7 V. - Abstract: A new hyperbranched multi-arm star polymer with hyperbranched polystyrene (HBPS) as core and polymethyl methacrylate-block-poly(ethylene glycol) methyl ether methacrylate(PMMA-b-PPEGMA) as arms was firstly synthesized by atom transfer radical polymerization. The obtained hyperbranched multi-arm star polymer (HBPS-(PMMA-b-PPEGMA)_x) exhibited good thermal stability with a thermal decomposition temperature of 372 °C. The transparent, free-standing, flexible polymer electrolyte film of the blending of HBPS-(PMMA-b-PPEGMA)_x and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) was successfully fabricated by a solution casting method. The ionic conductivity of the hyperbranched star polymer electrolyte with a molar ratio of [EO]/[Li] of 30 could reach 8.3 × 10"−"5 S cm"−"1 at 30 °C (with the content of PPEGMA of 83.7%), and 2.0 × 10"−"4 S cm"−"1 at 80 °C (with the content of PPEGMA of 51.6%). The effect of the concentration of lithium salts on ionic conductivity was also investigated. The obtained all-solid-state polymer electrolyte possessed a wide electrochemical stability window of 4.7 V (vs. Li"+/Li), and a lithium-ion transference number (t_L_i"+) up to 0.31. The interfacial impedance of the fabricated LiÔöépolymer electrolyteÔöéLi symmetric cell based on hyperbranched star multi-arm polymer electrolyte exhibited good interfacial compatibility between all-solid-state polymer electrolyte and electrodes. The excellent properties of the hyperbranched star polymer electrolyte made it attractive as solid-state polymer electrolyte for lithium-ion batteries.

  10. Negative Refraction Angular Characterization in One-Dimensional Photonic Crystals

    OpenAIRE

    Lugo, Jesus Eduardo; Doti, Rafael; Faubert, Jocelyn

    2011-01-01

    Background Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here we experimentally characterize negative refraction in a one dimensional photonic crystal structure; near the low frequency edge of the fourth photonic bandgap. We compare the experimental results with current theory and a theory based on the group velocity de...

  11. High-performance all-solid-state flexible supercapacitors based on two-step activated carbon cloth

    Science.gov (United States)

    Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Long, Hu; Xi, Shuang; Hu, Hao; Tang, Zirong

    2014-12-01

    A simple and effective strategy is proposed to activate carbon cloth for the fabrication of flexible and high-performance supercapacitors. Firstly, the carbon cloth surface is exfoliated as nanotextures through wet chemical treatment, then an annealing process is applied at H2/N2 atmosphere to reduce the surface oxygen functional groups which are mainly introduced from the first step. The activated carbon cloth electrode shows excellent wettablity, large surface area and delivers remarkable electrochemical performance. A maximum areal capacitance of 485.64 mF cm-2 at the current density of 2 mA cm-2 is achieved for the activated carbon cloth electrode, which is considerably larger than the resported results for carbon cloth. Furthermore, the flexible all-solid-state supercapacitor, which is fabricated based on the activated carbon cloth electrodes, shows high areal capacitance, superior cycling stability as well as stable electrochemical performance even under constant bending or twisting conditions. An areal capacitance of 161.28 mF cm-2 is achieved at the current density of 12.5 mA cm-2, and 104% of its initial capacitance is retained after 30,000 charging/discharging cycles. This study would also provide an effective way to boost devices' electrochemical performance by accommodating other active materials on the activated carbon cloth.

  12. High Performance All-solid Supercapacitors Based on the Network of Ultralong Manganese dioxide/Polyaniline Coaxial Nanowires

    Science.gov (United States)

    Zhou, Junli; Yu, Lin; Liu, Wei; Zhang, Xiaodan; Mu, Wei; Du, Xu; Zhang, Zhe; Deng, Yulin

    2015-12-01

    In recent years, thin, lightweight and flexible solid supercapacitors are of considerable interest as energy storage devices. Here we demonstrated all-solid supercapacitors (SSCs) with high electrochemical properties, low self-discharge characteristics based on manganese dioxide/polyaniline (MNW/PANI) coaxial nanowire networks. The synergistic effect of MnO2/PANI plus the unique coaxial nanostructure of the ultralong nanowires with a highly interconnected network effectively enhance the conductivity and capacitive performance of the SSCs device. The MNW/PANI composite with 62.5% MnO2 exhibits an outstanding areal specific capacitance reaching 346 mF/cm2 at 5 mV s-1 which is significant higher than most previously reported solid supercapacitors (15.3 mF/cm2-109 mF/cm2) and is close to the that of the best graphene films solid state supercapacitors (372 mF/cm2). In contrast, only 190 mF/cm2 of areal specific capacitance was obtained for the pure MnO2 NW network. The supercapacitors also exhibited low leakage current as small as 20.1 μA, which demonstrated that the MNW/PANI SSCs have great potential for practical applications.

  13. Densely-packed graphene/conducting polymer nanoparticle papers for high-volumetric-performance flexible all-solid-state supercapacitors

    Science.gov (United States)

    Yang, Chao; Zhang, Liling; Hu, Nantao; Yang, Zhi; Wei, Hao; Xu, Zhichuan J.; Wang, Yanyan; Zhang, Yafei

    2016-08-01

    Graphene-based all-solid-state supercapacitors (ASSSCs) are one of the most ideal candidates for high-performance flexible power sources. The achievement of high volumetric energy density is highly desired for practical application of this type of ASSSCs. Here, we present a facile method to boost volumetric performances of graphene-based flexible ASSSCs through incorporation of ultrafine polyaniline-poly(4-styrenesulfonate) (PANI-PSS) nanoparticles in reduced graphene oxide (rGO) papers. A compact structure is obtained via intimate contact and π-π interaction between PANI-PSS nanoparticles and rGO sheets. The hybrid paper electrode with the film thickness of 13.5 μm, shows an extremely high volumetric specific capacitance of 272 F/cm3 (0.37 A/cm3 in a three-electrode cell). The assembled ASSSCs show a large volumetric specific capacitance of 217 F/cm3 (0.37 A/cm3 in a two-electrode cell), high volumetric energy and power density, excellent capacitance stability, small leakage current as well as low self-discharge characteristics, revealing the usefulness of this robust hybrid paper for high-performance flexible energy storage devices.

  14. High-performance flexible all-solid-state supercapacitors based on densely-packed graphene/polypyrrole nanoparticle papers

    Science.gov (United States)

    Yang, Chao; Zhang, Liling; Hu, Nantao; Yang, Zhi; Wei, Hao; Wang, Yanyan; Zhang, Yafei

    2016-11-01

    Graphene-based all-solid-state supercapacitors (ASSSCs) have received increasing attention. It's a great challenge to fabricate high-performance flexible solid-state supercapacitors with high areal and volumetric energy storage capability, superior electron and ion conductivity, robust mechanical flexibility, as well as long term stability. Herein, we report a facile method to fabricate flexible ASSSCs based on densely-packed reduced graphene oxide (rGO)/polypyrrole nanoparticle (PPy NP) hybrid papers with a sandwich framework, which consists of well-separated and continuously-aligned rGO sheets. The incorporation of PPy NPs not only provides pseudocapacitance but also facilitates the infiltration of gel electrolyte. The assembled ASSSCs possess maximum areal and volumetric specific capacitances of 477 mF/cm2 and 94.9 F/cm3 at 0.5 mA/cm2. They also exhibit little capacitance deviation under different bending states, excellent cycling stability, small leakage current and low self-discharge characteristics. Additionally, the maximum areal and volumetric energy densities of 132.5 μWh/cm2 and 26.4 mWh/cm3 are achieved, which indicate that this hybrid paper is a promising candidate for high-performance flexible energy storage devices.

  15. An All-Solid-State Fiber-Shaped Aluminum-Air Battery with Flexibility, Stretchability, and High Electrochemical Performance.

    Science.gov (United States)

    Xu, Yifan; Zhao, Yang; Ren, Jing; Zhang, Ye; Peng, Huisheng

    2016-07-04

    Owing to the high theoretical energy density of metal-air batteries, the aluminum-air battery has been proposed as a promising long-term power supply for electronics. However, the available energy density from the aluminum-air battery is far from that anticipated and is limited by current electrode materials. Herein we described the creation of a new family of all-solid-state fiber-shaped aluminum-air batteries with a specific capacity of 935 mAh g(-1) and an energy density of 1168 Wh kg(-1) . The synthesis of an electrode composed of cross-stacked aligned carbon-nanotube/silver-nanoparticle sheets contributes to the remarkable electrochemical performance. The fiber shape also provides the aluminum-air batteries with unique advantages; for example, they are flexible and stretchable and can be woven into a variety of textiles for large-scale applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High Performance All-solid Supercapacitors Based on the Network of Ultralong Manganese dioxide/Polyaniline Coaxial Nanowires.

    Science.gov (United States)

    Zhou, Junli; Yu, Lin; Liu, Wei; Zhang, Xiaodan; Mu, Wei; Du, Xu; Zhang, Zhe; Deng, Yulin

    2015-12-08

    In recent years, thin, lightweight and flexible solid supercapacitors are of considerable interest as energy storage devices. Here we demonstrated all-solid supercapacitors (SSCs) with high electrochemical properties, low self-discharge characteristics based on manganese dioxide/polyaniline (MNW/PANI) coaxial nanowire networks. The synergistic effect of MnO2/PANI plus the unique coaxial nanostructure of the ultralong nanowires with a highly interconnected network effectively enhance the conductivity and capacitive performance of the SSCs device. The MNW/PANI composite with 62.5% MnO2 exhibits an outstanding areal specific capacitance reaching 346 mF/cm(2) at 5 mV s(-1) which is significant higher than most previously reported solid supercapacitors (15.3 mF/cm(2)-109 mF/cm(2)) and is close to the that of the best graphene films solid state supercapacitors (372 mF/cm(2)). In contrast, only 190 mF/cm(2) of areal specific capacitance was obtained for the pure MnO2 NW network. The supercapacitors also exhibited low leakage current as small as 20.1 μA, which demonstrated that the MNW/PANI SSCs have great potential for practical applications.

  17. Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors.

    Science.gov (United States)

    Zheng, Qifeng; Cai, Zhiyong; Ma, Zhenqiang; Gong, Shaoqin

    2015-02-11

    A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4/poly(vinyl alcohol) (PVA) gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors were fabricated without any binders, current collectors, or electroactive additives. Because of the porous structure of the CNF/RGO/CNT aerogel electrodes and the excellent electrolyte absorption properties of the CNFs present in the aerogel electrodes, the resulting flexible supercapacitors exhibited a high specific capacitance (i.e., 252 F g(-1) at a discharge current density of 0.5 A g(-1)) and a remarkable cycle stability (i.e., more than 99.5% of the capacitance was retained after 1000 charge-discharge cycles at a current density of 1 A g(-1)). Furthermore, the supercapacitors also showed extremely high areal capacitance, areal power density, and energy density (i.e., 216 mF cm(-2), 9.5 mW cm(-2), and 28.4 μWh cm(-2), respectively). In light of its excellent electrical performance, low cost, ease of large-scale manufacturing, and environmental friendliness, the CNF/RGO/CNT aerogel electrodes may have a promising application in the development of flexible energy-storage devices.

  18. Rapid determination of cadmium in rice using an all-solid RGO-enhanced light addressable potentiometric sensor.

    Science.gov (United States)

    Zhang, Wen; Xu, Yiwei; Zou, Xiaobo

    2018-09-30

    Herein, an all-solid light addressable potentiometric sensor (LAPS) is presented for determination of cadmium (Cd) in rice. On the working surface of the LAPS, reduced graphene oxide (RGO) is introduced as a part of ion-to-electron transducer to improve ionophore behaviors. The composite modification of RGO and ionophore is validated with scanning electron microscopy. The as-fabricated sensor presents a rapid response in less than 10 s to target Cd. Meanwhile, it shows lower noise (0.23 mV) and better limit of detection (0.002 mg L -1 ) than LAPS (control) without RGO modification (0.37 mV; 0.008 mg L -1 ). With the proposed method, satisfactory precision, accuracy and selectivity are also established. This method is adopted in an extensive survey for 25 rice samples from 5 regions in China. The results are in very good agreement with those obtained using inductively-coupled plasma-mass spectrometry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

    Science.gov (United States)

    Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

    2015-03-01

    We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm-1), light weight (1 mg cm-2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

  20. A Facile Methodology for the Development of a Printable and Flexible All-Solid-State Rechargeable Battery.

    Science.gov (United States)

    De, Bibekananda; Yadav, Amit; Khan, Salman; Kar, Kamal K

    2017-06-14

    Development of printable and flexible energy storage devices is one of the most promising technologies for wearable electronics in textile industry. The present work involves the design of a printable and flexible all-solid-state rechargeable battery for wearable electronics in textile applications. Copper-coated carbon fiber is used to make a poly(ethylene oxide) (PEO)-based polymer nanocomposite for a flexible and conductive current collector layer. Lithium iron phosphate (LiFePO 4 ) and titanium dioxide (TiO 2 ) are utilized to prepare the cathode and anode layers, respectively, with PEO and carbon black composites. The PEO- and Li salt-based solid composite separator layer is utilized for the solid-state and safe electrolyte. Fabrication of all these layers and assembly of them through coating on fabrics are performed in the open atmosphere without using any complex processing, as PEO prevents the degradation of the materials in the open atmosphere. The performance of the battery is evaluated through charge-discharge and open-circuit voltage analyses. The battery shows an open-circuit voltage of ∼2.67 V and discharge time ∼2000 s. It shows similar performance at different repeated bending angles (0° to 180°) and continuous bending along with long cycle life. The application of the battery is also investigated for printable and wearable textile applications. Therefore, this printable, flexible, easily processable, and nontoxic battery with this performance has great potential to be used in portable and wearable textile electronics.

  1. All-solid-state flexible supercapacitors based on papers coated with carbon nanotubes and ionic-liquid-based gel electrolytes

    International Nuclear Information System (INIS)

    Kang, Yu Jin; Kim, Woong; Chung, Haegeun; Han, Chi-Hwan

    2012-01-01

    All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf 2 ]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapacitor. The specific capacitance of the CNT electrodes was 135 F g −1 at a current density of 2 A g −1 , when considering the mass of active materials only. The maximum power and energy density of the supercapacitors were 164 kW kg −1 and 41 Wh kg −1 , respectively. Interestingly, the solid-state supercapacitor with the gel electrolyte showed comparable performance to the supercapacitors with ionic-liquid electrolyte. Moreover, the supercapacitor showed excellent stability and flexibility. The CNT/paper- and gel-based supercapacitors may hold great potential for low-cost and high-performance flexible energy storage applications. (paper)

  2. Modulated electron-multiplied fluorescence lifetime imaging microscope: all-solid-state camera for fluorescence lifetime imaging.

    Science.gov (United States)

    Zhao, Qiaole; Schelen, Ben; Schouten, Raymond; van den Oever, Rein; Leenen, René; van Kuijk, Harry; Peters, Inge; Polderdijk, Frank; Bosiers, Jan; Raspe, Marcel; Jalink, Kees; Geert Sander de Jong, Jan; van Geest, Bert; Stoop, Karel; Young, Ian Ted

    2012-12-01

    We have built an all-solid-state camera that is directly modulated at the pixel level for frequency-domain fluorescence lifetime imaging microscopy (FLIM) measurements. This novel camera eliminates the need for an image intensifier through the use of an application-specific charge coupled device design in a frequency-domain FLIM system. The first stage of evaluation for the camera has been carried out. Camera characteristics such as noise distribution, dark current influence, camera gain, sampling density, sensitivity, linearity of photometric response, and optical transfer function have been studied through experiments. We are able to do lifetime measurement using our modulated, electron-multiplied fluorescence lifetime imaging microscope (MEM-FLIM) camera for various objects, e.g., fluorescein solution, fixed green fluorescent protein (GFP) cells, and GFP-actin stained live cells. A detailed comparison of a conventional microchannel plate (MCP)-based FLIM system and the MEM-FLIM system is presented. The MEM-FLIM camera shows higher resolution and a better image quality. The MEM-FLIM camera provides a new opportunity for performing frequency-domain FLIM.

  3. Emerging applications of spark plasma sintering in all solid-state lithium-ion batteries and beyond

    Science.gov (United States)

    Zhu, Hongzheng; Liu, Jian

    2018-07-01

    Solid-state batteries have received increasing attention due to their high safety aspect and high energy and power densities. However, the development of solid-state batteries is hindered by inferior solid-solid interfaces between the solid-state electrolyte and electrode, which cause high interfacial resistance, reduced Li-ion and electron transfer rate, and limited battery performance. Recently, spark plasma sintering (SPS) is emerging as a promising technique for fabricating solid-state electrolyte and electrode pellets with clean and intimate solid-solid interfaces. During the SPS process, the unique reaction mechanism through the combination of current, pressure and high heating rate allow the formation of desirable solid-solid interfaces between active material particles. Herein, this work focuses on the overview of the application of SPS for fabricating solid-state electrolyte and electrode in all solid-state Li-ion batteries, and beyond, such as solid-state Li-S and Na-ion batteries. The correlations among SPS parameters, interfacial resistance, and electrochemical properties of solid-state electrolytes and electrodes are discussed for different material systems. In the end, we point out future opportunities and challenges associated with SPS application in the hot area of solid-state batteries. It is expected that this timely review will stimulate more fundamental and applied research in the development of solid-state batteries by SPS.

  4. All-solid tellurite optical fiber with transversely disordered refractive index profile and its optical image transport performance

    Science.gov (United States)

    Tong, Hoang Tuan; Kuroyanagi, Shunei; Suzuki, Takenobu; Ohishi, Yasutake

    2018-02-01

    All-solid tellurite-glass optical rod and fiber with transversely-disordered refractive index profile were successfully fabricated to study the transport of infrared images by using transverse localization of light. The fabrication was carried out by using stack-and-draw and rod-in-tube techniques. The fabricated tellurite optical rod and fiber were composed of high-index and low-index units which were arranged randomly in the transverse plane but were invariant in the longitudinal direction. The diameter of each unit was approximately 1.0 μm. The high-index and low-index materials were TeO2-Li2O-WO3-MoO3-Nb2O5 (TLWMN) glass and TeO2-ZnO-Na2O-La2O3 (TZNL) glass, respectively. At 1550 nm, their refractive index difference Δn is 0.096. To investigate the optical image transport capability, A CW laser light at 1550 nm was used as an input probe beam and the 1951 U.S. Air Force test target was installed in front of 10-cm-long segments of the fabricated rod and fiber in the experimental setup. The output signal was recorded by a beam profiler. As a result, clear transported images of numbers and lines on the test target were obtained.

  5. Scalable synthesis of freestanding sandwich-structured graphene/polyaniline/graphene nanocomposite paper for flexible all-solid-state supercapacitor.

    Science.gov (United States)

    Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

    2015-03-23

    We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm(-1)), light weight (1 mg cm(-2)) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

  6. One-step electrochemically expanded graphite foil for flexible all-solid supercapacitor with high rate performance

    International Nuclear Information System (INIS)

    Li, Han-Yu; Yu, Yao; Liu, Lang; Liu, Lin; Wu, Yue

    2017-01-01

    Flexible solid-state supercapacitors (SSCs) as a candidate for energy storage source, have been attracting intensive attention. Graphene-based materials for SSCs have been widely studied. However, most reported preparation methods for graphene-based materials are energy-consuming, time-consuming and environmentally hazardous, what’s more, the assembling of SSCs need additives, such as current collectors, flexible substrates. So, it is necessary to develop simpler and greener attempts to achieve high-performance, cost-effective, substrates/additives-free and flexible electrodes for SSC devices. Herein, we reported a green and facile one-step process of electrochemical oxidation and expansion in salt solution to activate graphite foil (GF) for fabricating expanded graphite foil (EGF). The EGF electrode with unique structure and high conductivity showed high supercapacitor performance of 65 mF cm −2 , remarkable rate-capability maintaining at a level of 80% even at a current density of 20 mA cm −2 and excellent cycling stability with ∼95% capacitance remaining after 10000 cycles at a current density of 20 mA cm −2 . Moreover, a symmetric flexible all-solid supercapacitor (SSC) device was integrated using EGFs without any current collectors and additives. The flexible EGF-based device showed a high capacitance capacity of 30.5 mF cm −2 , excellent rate performance and good cycle stability which make it holds promise for applications in flexible, portable and wearable electronic devices.

  7. Review of wide band-gap semiconductors technology

    Directory of Open Access Journals (Sweden)

    Jin Haiwei

    2016-01-01

    Full Text Available Silicon carbide (SiC and gallium nitride (GaN are typical representative of the wide band-gap semiconductor material, which is also known as third-generation semiconductor materials. Compared with the conventional semiconductor silicon (Si or gallium arsenide (GaAs, wide band-gap semiconductor has the wide band gap, high saturated drift velocity, high critical breakdown field and other advantages; it is a highly desirable semiconductor material applied under the case of high-power, high-temperature, high-frequency, anti-radiation environment. These advantages of wide band-gap devices make them a hot spot of semiconductor technology research in various countries. This article describes the research agenda of United States and European in this area, focusing on the recent developments of the wide band-gap technology in the US and Europe, summed up the facing challenge of the wide band-gap technology.

  8. Near-infrared sub-bandgap all-silicon photodetectors: state of the art and perspectives.

    Science.gov (United States)

    Casalino, Maurizio; Coppola, Giuseppe; Iodice, Mario; Rendina, Ivo; Sirleto, Luigi

    2010-01-01

    Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

  9. Near-Infrared Sub-Bandgap All-Silicon Photodetectors: State of the Art and Perspectives

    Directory of Open Access Journals (Sweden)

    Luigi Sirleto

    2010-11-01

    Full Text Available Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

  10. Bandgap engineering of InGaAsP/InP laser structure by photo-absorption-induced point defects

    Science.gov (United States)

    Kaleem, Mohammad; Nazir, Sajid; Saqib, Nazar Abbas

    2016-03-01

    Integration of photonic components on the same photonic wafer permits future optical communication systems to be dense and advanced performance. This enables very fast information handling between photonic active components interconnected through passive optical low loss channels. We demonstrate the UV-Laser based Quantum Well Intermixing (QWI) procedure to engineer the band-gap of compressively strained InGaAsP/InP Quantum Well (QW) laser material. We achieved around 135nm of blue-shift by simply applying excimer laser (λ= 248nm). The under observation laser processed material also exhibits higher photoluminescence (PL) intensity. Encouraging experimental results indicate that this simple technique has the potential to produce photonic integrated devices and circuits.

  11. Freedom from band-gap slavery: from diode lasers to quantum cascade lasers

    Science.gov (United States)

    Capasso, Federico

    2010-02-01

    Semiconductor heterostructure lasers, for which Alferov and Kromer received part of the Nobel Prize in Physics in 2000, are the workhorse of technologies such as optical communications, optical recording, supermarket scanners, laser printers and fax machines. They exhibit high performance in the visible and near infrared and rely for their operation on electrons and holes emitting photons across the semiconductor bandgap. This mechanism turns into a curse at longer wavelengths (mid-infrared) because as the bandgap, shrinks laser operation becomes much more sensitive to temperature, material defects and processing. Quantum Cascade Laser (QCL), invented in 1994, rely on a radically different process for light emission. QCLs are unipolar devices in which electrons undergo transitions between quantum well energy levels and are recycled through many stages emitting a cascade of photons. Thus by suitable tailoring of the layers' thickness, using the same heterostructure material, they can lase across the molecular fingerprint region from 3 to 25 microns and beyond into the far-infrared and submillimiter wave spectrum. High power cw room temperature QCLs and QCLs with large continuous single mode tuning range have found many applications (infrared countermeasures, spectroscopy, trace gas analysis and atmospheric chemistry) and are commercially available. )

  12. Search for chameleon particles via photon regeneration

    International Nuclear Information System (INIS)

    Chou, Aaron S.; CCPP, New York U.

    2008-01-01

    We report the first results from the GammeV search for chameleon particles, which may be created via photon-photon interactions within a strong magnetic field. The chameleons are assumed to have matter effects sufficiently strong that they reflect from all solid surfaces of the apparatus, thus evading detection in our previous search for weakly-interacting axion-like particles. We implement a novel technique to create and trap the reflective particles within a jar and to detect them later via their afterglow as they slowly convert back into photons. These measurements provide the first experimental constraints on the couplings of chameleons to photons

  13. An All-Solid-State, Room-Temperature, Heterodyne Receiver for Atmospheric Spectroscopy at 1.2 THz

    Science.gov (United States)

    Siles, Jose V.; Mehdi, Imran; Schlecht, Erich T.; Gulkis, Samuel; Chattopadhyay, Goutam; Lin, Robert H.; Lee, Choonsup; Gill, John J.; Thomas, Bertrand; Maestrini, Alain E.

    2013-01-01

    Heterodyne receivers at submillimeter wavelengths have played a major role in astrophysics as well as Earth and planetary remote sensing. All-solid-state heterodyne receivers using both MMIC (monolithic microwave integrated circuit) Schottky-diode-based LO (local oscillator) sources and mixers are uniquely suited for long-term planetary missions or Earth climate monitoring missions as they can operate for decades without the need for any active cryogenic cooling. However, the main concern in using Schottky-diode-based mixers at frequencies beyond 1 THz has been the lack of enough LO power to drive the devices because 1 to 3 mW are required to properly pump Schottky diode mixers. Recent progress in HEMT- (high-electron-mobility- transistor) based power amplifier technology, with output power levels in excess of 1 W recently demonstrated at W-band, as well as advances in MMIC Schottky diode circuit technology, have led to measured output powers up to 1.4 mW at 0.9 THz. Here the first room-temperature tunable, all-planar, Schottky-diode-based receiver is reported that is operating at 1.2 THz over a wide (˜20%) bandwidth. The receiver front-end (see figure) consists of a Schottky-diode-based 540 to 640 GHz multiplied LO chain (featuring a cascade of W-band power amplifiers providing around 120 to 180 mW at W-band), a 200-GHz MMIC frequency doubler, and a 600-GHz MMIC frequency tripler, plus a biasable 1.2-THz MMIC sub-harmonic Schottky-diode mixer. The LO chain has been designed, fabricated, and tested at JPL and provides around 1 to 1.5 mW at 540 o 640 GHz. The sub-harmonic mixer consists of two Schottky diodes on a thin GaAs membrane in an anti-parallel configuration. An integrated metal insulator metal (MIM) capacitor has been included on-chip to allow dc bias for the Schottky diodes. A bias voltage of around 0.5 V/diode is necessary to reduce the LO power required down to the 1 to 1.5 mW available from the LO chain. The epilayer thickness and doping profiles have

  14. All-solid-state potentiometric sensors for ascorbic acid by using a screen-printed compatible solid contact

    International Nuclear Information System (INIS)

    Veltsistas, Panayotis G.; Prodromidis, Mamas I.; Efstathiou, Constantinos

    2004-01-01

    The development of all-solid-state potentiometric ion selective electrodes for monitoring of ascorbic acid, by using a screen-printed compatible solid contact is described. The applied methodology is based on the use of PVC membrane modified with some firstly-tested ionophores (triphenyltin(IV)chloride, triphenyltin(IV)hydroxide and palmitoyl-L-ascorbic acid) and a novel one synthesized in our laboratory (dibutyltin(IV) diascorbate). Synthesis protocol and some preliminary identification studies are given. A conductive graphite-based polymer thick film ink was used as an internal solid contact between the graphite electrode and the PVC membrane. The presence and the nature of the solid contact (plain or doped with lanthanum 2,6-dichlorophenolindophenol (DCPI)) seem to enhance the analytical performance of the electrodes in terms of sensitivity, dynamic range, and response time. The analytical performance of the constructed electrodes was evaluated with potentiometry, constant-current chronopotentiometry and electrochemical impedance spectroscopy (EIS). The interference effect of various compounds was also tested. The potential response of the optimized Ph 3 SnCl-based electrode was linear against ascorbic acid concentration range 0.005-5.0 mM. The applicability of the proposed sensors in real samples was also tested. The detection limit was 0.002 mM ascorbic acid (50 mM phosphate, pH 5 in 50 mM KCl). The slope of the electrodes was super-Nernstian and pH dependent, indicating a mechanism involving a combination of charge transfer and ion exchange processes. Fabrication of screen-printed ascorbate ISEs has also been demonstrated

  15. High-Performance All-Solid-State Na-S Battery Enabled by Casting-Annealing Technology.

    Science.gov (United States)

    Fan, Xiulin; Yue, Jie; Han, Fudong; Chen, Ji; Deng, Tao; Zhou, Xiuquan; Hou, Singyuk; Wang, Chunsheng

    2018-04-24

    Room-temperature all-solid-state Na-S batteries (ASNSBs) using sulfide solid electrolytes are a promising next-generation battery technology due to the high energy, enhanced safety, and earth abundant resources of both sodium and sulfur. Currently, the sulfide electrolyte ASNSBs are fabricated by a simple cold-pressing process leaving with high residential stress. Even worse, the large volume change of S/Na 2 S during charge/discharge cycles induces additional stress, seriously weakening the less-contacted interfaces among the solid electrolyte, active materials, and the electron conductive agent that are formed in the cold-pressing process. The high and continuous increase of the interface resistance hindered its practical application. Herein, we significantly reduce the interface resistance and eliminate the residential stress in Na 2 S cathodes by fabricating Na 2 S-Na 3 PS 4 -CMK-3 nanocomposites using melting-casting followed by stress-release annealing-precipitation process. The casting-annealing process guarantees the close contact between the Na 3 PS 4 solid electrolyte and the CMK-3 mesoporous carbon in mixed ionic/electronic conductive matrix, while the in situ precipitated Na 2 S active species from the solid electrolyte during the annealing process guarantees the interfacial contact among these three subcomponents without residential stress, which greatly reduces the interfacial resistance and enhances the electrochemical performance. The in situ synthesized Na 2 S-Na 3 PS 4 -CMK-3 composite cathode delivers a stable and highly reversible capacity of 810 mAh/g at 50 mA/g for 50 cycles at 60 °C. The present casting-annealing strategy should provide opportunities for the advancement of mechanically robust and high-performance next-generation ASNSBs.

  16. Synthesis and characterization of hierarchical Bi2MoO6/Polyaniline nanocomposite for all-solid-state asymmetric supercapacitor

    International Nuclear Information System (INIS)

    Wu, Fangsheng; Wang, Xiaohong; Zheng, Wanru; Gao, Haiwen; Hao, Chen; Ge, Cunwang

    2017-01-01

    Bi 2 MoO 6 /Polyaniline (PANI) hybrid nanocomposite with enhanced specific capacity and rate performance was synthesized by compositing Bi 2 MoO 6 with the PANI layer using sodium lignosulphonate (SLS) as a dopant through a simple chemical polymerization. The Bi 2 MoO 6 /PANI (BMP) nanocomposite affords a large reaction surface area, an excellent structural stability, a large number of active sites, good strain accommodation, and fast electron and ion transportation compared with pure Bi 2 MoO 6 , which all are beneficial for improving the electrochemical performance. Hence, the Bi 2 MoO 6 /PANI electrode with 0.15 g Bi 2 MoO 6 (BMP-2) shows a high specific capacitance of 826 F g −1 at a current density of 1 A g −1 and capacitance retention of 75.5% after 3000 cycles at a current density of 5 A g −1 , which is higher than pristine Bi 2 MoO 6 and other electrodes. In addition, an all-solid-state asymmetric supercapacitor (ASC) fabricated by the BMP-2 electrode and activated carbon (AC) displays a high specific capacitance of 90.0 F g −1 and a high energy density of 31.9 Wh kg −1 . Moreover, the BMP-2//AC ASC device exhibits high cycle stability, and 86.5% of its initial capacitance is retained after continuous 6000 cycles. Therefore, these results will promote a promising potential application of the Bi 2 MoO 6 /PANI nanocomposite for use as an effective electrode material in supercapacitors.

  17. Photon-photon collisions

    International Nuclear Information System (INIS)

    Burke, D.L.

    1982-10-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved

  18. Photon-photon collisions

    International Nuclear Information System (INIS)

    Haissinski, J.

    1986-06-01

    The discussions presented in this paper deal with the following points: distinctive features of gamma-gamma collisions; related processes; photon-photon elastic scattering in the continuum and γγ →gg; total cross section; γγ → V 1 V 2 (V=vector meson); radiative width measurements and light meson spectroscopy; exclusive channels at large /t/; jets and inclusive particle distribution in γγ collisions; and, the photon structure function F γ 2

  19. Graded photonic crystals by optical interference holography

    International Nuclear Information System (INIS)

    Han, Chunrui; Tam, Wing Yim

    2012-01-01

    We report on the fabrication of graded photonic crystals in dye doped dichromate gelatin emulsions using an optical interference holographic technique. The gradedness is achieved by imposing a gradient form factor in the interference intensity resulting from the absorption of the dye in the dichromate gelatin. Wider and deeper photonic bandgaps are observed for the dyed samples as compared to the un-dyed samples. Our method could open up a new direction in fabricating graded photonic crystals which cannot be achieved easily using other techniques. (paper)

  20. Amorphous photonic crystals with only short-range order.

    Science.gov (United States)

    Shi, Lei; Zhang, Yafeng; Dong, Biqin; Zhan, Tianrong; Liu, Xiaohan; Zi, Jian

    2013-10-04

    Distinct from conventional photonic crystals with both short- and long-range order, amorphous photonic crystals that possess only short-range order show interesting optical responses owing to their unique structural features. Amorphous photonic crystals exhibit unique light scattering and transport, which lead to a variety of interesting phenomena such as isotropic photonic bandgaps or pseudogaps, noniridescent structural colors, and light localization. Recent experimental and theoretical advances in the study of amorphous photonic crystals are summarized, focusing on their unique optical properties, artificial fabrication, bionspiration, and potential applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Photon-photon colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

  2. Engineering photonic density of states using metamaterials

    DEFF Research Database (Denmark)

    Jacob, Z.; Kim, J.Y.; Naik, G.V.

    2010-01-01

    The photonic density of states (PDOS), like its electronic counterpart, is one of the key physical quantities governing a variety of phenomena and hence PDOS manipulation is the route to new photonic devices. The PDOS is conventionally altered by exploiting the resonance within a device such as a......The photonic density of states (PDOS), like its electronic counterpart, is one of the key physical quantities governing a variety of phenomena and hence PDOS manipulation is the route to new photonic devices. The PDOS is conventionally altered by exploiting the resonance within a device...... such as a microcavity or a bandgap structure like a photonic crystal. Here we show that nanostructured metamaterials with hyperbolic dispersion can dramatically enhance the photonic density of states paving the way for metamaterial-based PDOS engineering....

  3. Unidirectional transmission in 1D nonlinear photonic crystal based on topological phase reversal by optical nonlinearity

    Directory of Open Access Journals (Sweden)

    Chong Li

    2017-02-01

    Full Text Available We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, bringing a topological phase reversal and results the topological edge mode arising at the interface which could transmit photons through the bandgaps both of the photonic crystal L and R. When the signal power intensity larger than a moderate low threshold value of 10.0 MW/cm2, the transmission contrast ratio could remain at 30 steadily.

  4. Nonlocal hyperconcentration on entangled photons using photonic module system

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhang, Ru [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Ethnic Minority Education, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wang, Chuan, E-mail: wangchuan@bupt.edu.cn [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2016-06-15

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  5. Nonlocal hyperconcentration on entangled photons using photonic module system

    International Nuclear Information System (INIS)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen; Zhang, Ru; Wang, Chuan

    2016-01-01

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  6. Bandgap tunability at single-layer molybdenum disulphide grain boundaries

    KAUST Repository

    Huang, Yu Li; Chen, Yifeng; Zhang, Wenjing; Quek, Su Ying; Chen, Chang-Hsiao; Li, Lain-Jong; Hsu, Wei-Ting; Chang, Wen-Hao; Zheng, Yu Jie; Chen, Wei; Wee, Andrew T. S.

    2015-01-01

    represents a prototype two-dimensional transition metal dichalcogenide, has an electronic bandgap that increases with decreasing layer thickness. Using high-resolution scanning tunnelling microscopy and spectroscopy, we measure the apparent quasiparticle

  7. WO{sub 3-x}/MoO{sub 3-x} core/shell nanowires on carbon fabric as an anode for all-solid-state asymmetric supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xu; Ding, Tianpeng; Yuan, Longyan; Shen, Yongqi; Zhong, Qize; Zhang, Xianghui; Cao, Yuanzhi; Hu, Bin; Zhou, Jun [Wuhan National Laboratory for Optoelectronics (WNLO), College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan (China); Zhai, Teng; Tong, Yexiang [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou (China); Gong, Li; Chen, Jian [Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou (China); Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    2012-11-15

    Flexible all-solid-state asymmetric supercapacitors (ASCs) are fabricated from a novel anode - WO{sub 3-x}/MoO{sub 3-x} core/shell nanowires on carbon fabric - and a polyaniline cathode (figure). In addition to the high electrochemical performance of the devices, other characteristics, such as low toxicity, flexibility, environmental compatibility, light weight, and low requirements for packaging, make the all-solid-state ASCs potential candidates for applications in energy storage, flexible electronics, and other consumer electronics. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Study on sensing property of one-dimensional ring mirror-defect photonic crystal

    Science.gov (United States)

    Chen, Ying; Luo, Pei; Cao, Huiying; Zhao, Zhiyong; Zhu, Qiguang

    2018-02-01

    Based on the photon localization and the photonic bandgap characteristics of photonic crystals (PCs), one-dimensional (1D) ring mirror-defect photonic crystal structure is proposed. Due to the introduction of mirror structure, a defect cavity is formed in the center of the photonic crystal, and then the resonant transmission peak can be obtained in the bandgap of transmission spectrum. The transfer matrix method is used to establish the relationship model between the resonant transmission peak and the structure parameters of the photonic crystals. Using the rectangular air gate photonic crystal structure, the dynamic monitoring of the detected gas sample parameters can be achieved from the shift of the resonant transmission peak. The simulation results show that the Q-value can attain to 1739.48 and the sensitivity can attain to 1642 nm ṡ RIU-1, which demonstrates the effectiveness of the sensing structure. The structure can provide certain theoretical reference for air pollution monitoring and gas component analysis.

  9. Four-terminal circuit element with photonic core

    Science.gov (United States)

    Sampayan, Stephen

    2017-08-29

    A four-terminal circuit element is described that includes a photonic core inside of the circuit element that uses a wide bandgap semiconductor material that exhibits photoconductivity and allows current flow through the material in response to the light that is incident on the wide bandgap material. The four-terminal circuit element can be configured based on various hardware structures using a single piece or multiple pieces or layers of a wide bandgap semiconductor material to achieve various designed electrical properties such as high switching voltages by using the photoconductive feature beyond the breakdown voltages of semiconductor devices or circuits operated based on electrical bias or control designs. The photonic core aspect of the four-terminal circuit element provides unique features that enable versatile circuit applications to either replace the semiconductor transistor-based circuit elements or semiconductor diode-based circuit elements.

  10. Large-bandwidth planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Lavrinenko, Andrei

    2002-01-01

    A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

  11. Complex layered materials and periodic electromagnetic band-gap structures: Concepts, characterizations, and applications

    Science.gov (United States)

    Mosallaei, Hossein

    The main objective of this dissertation is to characterize and create insight into the electromagnetic performances of two classes of composite structures, namely, complex multi-layered media and periodic Electromagnetic Band-Gap (EBG) structures. The advanced and diversified computational techniques are applied to obtain their unique propagation characteristics and integrate the results into some novel applications. In the first part of this dissertation, the vector wave solution of Maxwell's equations is integrated with the Genetic Algorithm (GA) optimization method to provide a powerful technique for characterizing multi-layered materials, and obtaining their optimal designs. The developed method is successfully applied to determine the optimal composite coatings for Radar Cross Section (RCS) reduction of canonical structures. Both monostatic and bistatic scatterings are explored. A GA with hybrid planar/curved surface implementation is also introduced to efficiently obtain the optimal absorbing materials for curved structures. Furthermore, design optimization of the non-uniform Luneburg and 2-shell spherical lens antennas utilizing modal solution/GA-adaptive-cost function is presented. The lens antennas are effectively optimized for both high gain and suppressed grating lobes. The second part demonstrates the development of an advanced computational engine, which accurately computes the broadband characteristics of challenging periodic electromagnetic band-gap structures. This method utilizes the Finite Difference Time Domain (FDTD) technique with Periodic Boundary Condition/Perfectly Matched Layer (PBC/PML), which is efficiently integrated with the Prony scheme. The computational technique is successfully applied to characterize and present the unique propagation performances of different classes of periodic structures such as Frequency Selective Surfaces (FSS), Photonic Band-Gap (PBG) materials, and Left-Handed (LH) composite media. The results are

  12. Photonic Crystal Emitters for Thermophotovoltaic Energy Conversion

    International Nuclear Information System (INIS)

    Stelmakh, Veronika; Chan, Walker R; Joannopoulos, John D; Celanovic, Ivan; Ghebrebrhan, Michael; Soljacic, Marin

    2015-01-01

    This paper reports the design, fabrication, and characterization of 2D photonic crystal (PhC) thermal emitters for a millimeter-scale hydrocarbon TPV microgenerator as a possible replacement for batteries in portable microelectronics, robotics, etc. In our TPV system, combustion heats a PhC emitter to incandescence and the resulting radiation is converted by a low-bandgap TPV cell. The PhC tailors the photonic density of states to produce spectrally confined thermal emission that matches the bandgap of the TPV cell, enabling high heat-to-electricity conversion efficiency. The work builds on a previously developed fabrication process to produce a square array of cylindrical cavities in a metal substrate. We will present ongoing incremental improvements in the optical and thermo-mechanical properties, the fabrication process, and the system integration, as recently combined with fabrication using novel materials, such as sputtered coatings, to enable a monolithic system. (paper)

  13. Wide Bandgap Semiconductor Opportunities in Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Marlino, Laura D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Kristina O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2018-01-01

    The report objective is to explore the Wide Bandgap (WBG) Power Electronics (PE) market, applications, and potential energy savings in order to identify key areas where further resources and investments of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE) would have the most impact on U.S. competiveness. After considering the current market, several potential near-term application areas were identified as having significant market and energy savings potential with respect to clean energy applications: (1) data centers (uninterruptible power supplies and server power supplies); (2) renewable energy generation (photovoltaic-solar and wind); (3) motor drives (industrial, commercial and residential); (4) rail traction; and, (5) hybrid and electric vehicles (traction and charging). After the initial explorative analyses, it became clear that, SiC, not GaN, would be the principal WBG power device material for the chosen markets in the near future. Therefore, while GaN is discussed when appropriate, this report focuses on SiC devices, other WBG applications (e.g., solid-state transformers, combined heat and power, medical, and wireless power), the GaN market, and GaN specific applications (e.g., LiDAR, 5G) will be explored at a later date. In addition to the market, supply and value chain analyses addressed in Section 1 of this report, a SWOT (Strength, Weakness, Opportunity, Threat) analysis and potential energy savings analysis was conducted for each application area to identify the major potential WBG application area(s) with a U.S. competitiveness opportunity in the future.

  14. All-solid state, flexible, high-energy integrated hybrid micro-supercapacitors based on 3D LSG/CoNi2S4 nanosheets.

    Science.gov (United States)

    Moosavifard, Seyyed Ebrahim; Shamsi, Javad; Altafi, Mohammad Kazem; Moosavifard, Zeinab Sadat

    2016-11-18

    3D LSG/CoNi 2 S 4 //LSG interdigitated microelectrodes have been firstly developed by a facile, scalable and low cost process for all-solid-state, flexible integrated asymmetric micro-supercapacitors. These devices can achieve energy densities of up to 49 W h l -1 which is comparable to those of lead acid batteries.

  15. 1,2,4-Triazolium perfluorobutanesulfonate as an archetypal pure protic organic ionic plastic crystal electrolyte for all-solid-state fuel cells

    DEFF Research Database (Denmark)

    Luo, Jiangshui; Jensen, Annemette Hindhede; Brooks, Neil R.

    2015-01-01

    1,2,4-Triazolium perfluorobutanesulfonate (1), a novel, pure protic organic ionic plastic crystal (POIPC) with a wide plastic crystalline phase, has been explored as a proof-of-principle anhydrous proton conductor for all-solid-state high temperature hydrogen/air fuel cells. Its physicochemical p...

  16. Rational coating of Li7P3S11 solid electrolyte on MoS2 electrode for all-solid-state lithium ion batteries

    Science.gov (United States)

    Xu, R. C.; Wang, X. L.; Zhang, S. Z.; Xia, Y.; Xia, X. H.; Wu, J. B.; Tu, J. P.

    2018-01-01

    Large interfacial resistance between electrode and electrolyte limits the development of high-performance all-solid-state batteries. Herein we report a uniform coating of Li7P3S11 solid electrolyte on MoS2 to form a MoS2/Li7P3S11 composite electrode for all-solid-state lithium ion batteries. The as-synthesized Li7P3S11 processes a high ionic of 2.0 mS cm-1 at room temperature. Due to homogeneous union and reduced interfacial resistance, the assembled all-solid-state batteries with the MoS2/Li7P3S11 composite electrode exhibit higher reversible capacity of 547.1 mAh g-1 at 0.1 C and better cycling stability than the counterpart based on untreated MoS2. Our study provides a new reference for design/fabrication of advanced electrode materials for high-performance all-solid-state batteries.

  17. Patterning of lithium lanthanum titanium oxide films by soft lithography as electrolyte for all-solid-state Li-ion batteries

    NARCIS (Netherlands)

    Kokal, I.; Göbel, Ole; van den Ham, E.J.; ten Elshof, Johan E.; Notten, P.H.L.; Hintzen, H.T.

    2015-01-01

    The combination of sol–gel processing and soft-lithographic patterning presents a promising route towards three-dimensional (3D) micro Li-ion electrodes, and may offer a viable approach for the fabrication of all-solid-state 3D Li-ion batteries. The methods are relatively simple and therefore cheap

  18. Patterning of lithium lanthanum titanium oxide films by soft lithography as electrolyte for all-solid-state Li-ion batteries

    NARCIS (Netherlands)

    Kokal, I.; Göbel, O.F.; van den Ham, E.J.; ten Elshof, J.E.; Notten, P.H.L.; Hintzen, H.T.

    2015-01-01

    The combination of sol-gel processing and soft-lithographic patterning presents a promising route towards three-dimensional (3D) micro Li-ion electrodes, and may offer a viable approach for the fabrication of all-solid-state 3D Li-ion batteries. The methods are relatively simple and therefore cheap

  19. Densely Aligned Graphene Nanoribbon Arrays and Bandgap Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Su, Justin [Stanford Univ., CA (United States); Chen, Changxin [Stanford Univ., CA (United States); Gong, Ming [Stanford Univ., CA (United States); Kenney, Michael [Stanford Univ., CA (United States)

    2017-01-04

    Graphene has attracted great interest for future electronics due to its high mobility and high thermal conductivity. However, a two-dimensional graphene sheet behaves like a metal, lacking a bandgap needed for the key devices components such as field effect transistors (FETs) in digital electronics. It has been shown that, partly due to quantum confinement, graphene nanoribbons (GNRs) with ~2 nm width can open up sufficient bandgaps and evolve into semiconductors to exhibit high on/off ratios useful for FETs. However, a challenging problem has been that, such ultra-narrow GNRs (~2 nm) are difficult to fabricate, especially for GNRs with smooth edges throughout the ribbon length. Despite high on/off ratios, these GNRs show very low mobility and low on-state conductance due to dominant scattering effects by imperfections and disorders at the edges. Wider GNRs (>5 nm) show higher mobility, higher conductance but smaller bandgaps and low on/off ratios undesirable for FET applications. It is highly desirable to open up bandgaps in graphene or increase the bandgaps in wide GNRs to afford graphene based semiconductors for high performance (high on-state current and high on/off ratio) electronics. Large scale ordering and dense packing of such GNRs in parallel are also needed for device integration but have also been challenging thus far. It has been shown theoretically that uniaxial strains can be applied to a GNR to engineer its bandgap. The underlying physics is that under uniaxial strain, the Dirac point moves due to stretched C-C bonds, leading to an increase in the bandgap of armchair GNRs by up to 50% of its original bandgap (i.e. bandgap at zero strain). For zigzag GNRs, due to the existence of the edge states, changes of bandgap are smaller under uniaxial strain and can be increased by ~30%. This work proposes a novel approach to the fabrication of densely aligned graphene nanoribbons with highly smooth edges afforded by anisotropic etching and uniaxial strain for

  20. Electronic band-gap modified passive silicon optical modulator at telecommunications wavelengths.

    Science.gov (United States)

    Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Liu, Xiangdong; Lu, Qingming; Wang, Jiyang

    2015-11-13

    The silicon optical modulator is considered to be the workhorse of a revolution in communications. In recent years, the capabilities of externally driven active silicon optical modulators have dramatically improved. Self-driven passive modulators, especially passive silicon modulators, possess advantages in compactness, integration, low-cost, etc. Constrained by a large indirect band-gap and sensitivity-related loss, the passive silicon optical modulator is scarce and has been not advancing, especially at telecommunications wavelengths. Here, a passive silicon optical modulator is fabricated by introducing an impurity band in the electronic band-gap, and its nonlinear optics and applications in the telecommunications-wavelength lasers are investigated. The saturable absorption properties at the wavelength of 1.55 μm was measured and indicates that the sample is quite sensitive to light intensity and has negligible absorption loss. With a passive silicon modulator, pulsed lasers were constructed at wavelengths at 1.34 and 1.42 μm. It is concluded that the sensitive self-driven passive silicon optical modulator is a viable candidate for photonics applications out to 2.5 μm.

  1. Coupling of single quantum dots to a photonic crystal waveguide

    DEFF Research Database (Denmark)

    Lund-Hansen, Toke; Stobbe, Søren; Julsgaard, Brian

    Efficient and high quality single-photon sources is a key element in quantum information processing using photons. As a consequence, much current research is focused on realizing all-solid-state nanophotonic single-photon sources. Single photons can be harvested with high efficiency if the emitter...... is coupled efficiently to a single enhanced mode. One popular approach has been to couple single quantum dots to a nanocavity but a limiting factor in this configuration is that in order to apply the photon it should subsequently be coupled out of the cavity, reducing the overall efficiency significantly...

  2. 1D Photonic Crystals with a Sawtooth Refractive Index

    OpenAIRE

    Morozov, G. V.; Sprung, D. W. L.; Martorell, J.

    2013-01-01

    Exact analytical results (in terms of Bessel functions) for the bandgaps, reflectance, and transmittance of one-dimensional photonic crystals with a sawtooth refractive index profile on the period are derived for the first time. This extends a group of exactly solvable models of periodic refractive indices. The asymptotic approximations of the above exact results have been also obtained.

  3. Harvesting the Full Potential of Photons with Organic Solar Cells.

    Science.gov (United States)

    Ran, Niva A; Love, John A; Takacs, Christopher J; Sadhanala, Aditya; Beavers, Justin K; Collins, Samuel D; Huang, Ye; Wang, Ming; Friend, Richard H; Bazan, Guillermo C; Nguyen, Thuc-Quyen

    2016-02-17

    A low-bandgap polymer:fullerene blend that has significantly reduced energetic losses from photon absorption to VOC is described. The charge-transfer state and polymer singlet are of nearly equal energy, yet the short-circuit current still reaches 14 mA cm(-2). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Photon management with index-near-zero materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhu; Yu, Zongfu [Department of Electrical and Computer Engineering, University of Wisconsin Madison, Madison, Wisconsin 53706 (United States); Wang, Ziyu [Department of Foundation, Southeast University, Chengxian College, 210018 Nanjing (China)

    2016-08-01

    Index-near-zero materials can be used for effective photon management. They help to restrict the angle of acceptance, resulting in greatly enhanced light trapping limit. In addition, these materials also decrease the radiative recombination, leading to enhanced open circuit voltage and energy efficiency in direct bandgap solar cells.

  5. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  6. Photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references

  7. Photon-photon collisions

    International Nuclear Information System (INIS)

    Field, J.H.

    1984-01-01

    The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e + e - storage rings. After a complete presentation of the helicity amplitude formalism for the general process e + e - → Xe + e - , various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

  8. Mg2BIV: Narrow Bandgap Thermoelectric Semiconductors

    Science.gov (United States)

    Kim, Il-Ho

    2018-05-01

    Thermoelectric materials can convert thermal energy directly into electric energy and vice versa. The electricity generation from waste heat via thermoelectric devices can be considered as a new energy source. For instance, automotive exhaust gas and all industrial processes generate an enormous amount of waste heat that can be converted to electricity by using thermoelectric devices. Magnesium compound Mg2BIV (BIV = Si, Ge or Sn) has a favorable combination of physical and chemical properties and can be a good base for the development of new efficient thermoelectrics. Because they possess similar properties to those of group BIV elemental semiconductors, they have been recognized as good candidates for thermoelectric applications. Mg2Si, Mg2Ge and Mg2Sn with an antifluorite structure are narrow bandgap semiconductors with indirect band gaps of 0.77 eV, 0.74 eV, and 0.35 eV, respectively. Mg2BIV has been recognized as a promising material for thermoelectric energy conversion at temperatures ranging from 500 K to 800 K. Compared to other thermoelectric materials operating in the similar temperature range, such as PbTe and filled skutterudites, the important aspects of Mg2BIV are non-toxic and earth-abundant elements. Based on classical thermoelectric theory, the material factor β ( m* / m e)3/2μκ L -1 can be utilized as the criterion for thermoelectric material selection, where m* is the density-of-states effective mass, me is the mass of an electron, μ is the carrier mobility, and κL is the lattice thermal conductivity. The β for magnesium silicides is 14, which is very high compared to 0.8 for iron silicides, 1.4 for manganese silicides, and 2.6 for silicon-germanium alloys. In this paper, basic phenomena of thermoelectricity and transport parameters for thermoelectric materials were briefly introduced, and thermoelectric properties of Mg2BIV synthesized by using a solid-state reaction were reviewed. In addition, various Mg2BIV compounds were discussed

  9. Bandgap-customizable germanium using lithographically determined biaxial tensile strain for silicon-compatible optoelectronics.

    Science.gov (United States)

    Sukhdeo, David S; Nam, Donguk; Kang, Ju-Hyung; Brongersma, Mark L; Saraswat, Krishna C

    2015-06-29

    Strain engineering has proven to be vital for germanium-based photonics, in particular light emission. However, applying a large permanent biaxial tensile strain to germanium has been a challenge. We present a simple, CMOS-compatible technique to conveniently induce a large, spatially homogenous strain in circular structures patterned within germanium nanomembranes. Our technique works by concentrating and amplifying a pre-existing small strain into a circular region. Biaxial tensile strains as large as 1.11% are observed by Raman spectroscopy and are further confirmed by photoluminescence measurements, which show enhanced and redshifted light emission from the strained germanium. Our technique allows the amount of biaxial strain to be customized lithographically, allowing the bandgaps of different germanium structures to be independently customized in a single mask process.

  10. Growth of Bulk Wide Bandgap Semiconductor Crystals and Their Potential Applications

    Science.gov (United States)

    Chen, Kuo-Tong; Shi, Detang; Morgan, S. H.; Collins, W. Eugene; Burger, Arnold

    1997-01-01

    Developments in bulk crystal growth research for electro-optical devices in the Center for Photonic Materials and Devices since its establishment have been reviewed. Purification processes and single crystal growth systems employing physical vapor transport and Bridgman methods were assembled and used to produce high purity and superior quality wide bandgap materials such as heavy metal halides and II-VI compound semiconductors. Comprehensive material characterization techniques have been employed to reveal the optical, electrical and thermodynamic properties of crystals, and the results were used to establish improved material processing procedures. Postgrowth treatments such as passivation, oxidation, chemical etching and metal contacting during the X-ray and gamma-ray device fabrication process have also been investigated and low noise threshold with improved energy resolution has been achieved.

  11. Photoinduced local heating in silica photonic crystals for fast and reversible switching.

    Science.gov (United States)

    Gallego-Gómez, Francisco; Blanco, Alvaro; López, Cefe

    2012-12-04

    Fast and reversible photonic-bandgap tunability is achieved in silica artificial opals by local heating. The effect is fully reversible as heat rapidly dissipates through the non-irradiated structure without active cooling and water is readsorbed. The performance is strongly enhanced by decreasing the photoirradiated opal volume, allowing bandgap shifts of 12 nm and response times of 20 ms. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Phosphorene nanoribbons: Passivation effect on bandgap and effective mass

    International Nuclear Information System (INIS)

    Xu, Li-Chun; Song, Xian-Jiang; Yang, Zhi; Cao, Ling; Liu, Rui-Ping; Li, Xiu-Yan

    2015-01-01

    Highlights: • Hydrogenation and fluorination can passivate the metallic edge states of zPNRs. • The bandgap of each type of zPNRs decreases as the ribbon's width increases duo to the quantum confinement effect. • Two local configurations of passivated atoms can coexist in nanoribbons and affect the bandgap of narrow nanoribbons. • New passivation configuration can effectively reduce the effective mass of electrons. - Abstract: The edge passivation effect of phosphorene nanoribbons is systematically investigated using density functional theory. Hydrogen and fluorine atoms passivate the metallic edge states of nanoribbons and can open a bandgap up to 2.25 eV. The two configurations of passivated atoms can exist at two edges and affect the bandgap of narrow nanoribbons. The bandgap of each type of zPNRs decreases as the ribbon's width increases, which can be attributed to the quantum confinement effect. The new configuration, named C b , can effectively reduce the effective mass of electrons, which benefits the future design of phosphorene-based electronic devices

  13. Phosphorene nanoribbons: Passivation effect on bandgap and effective mass

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li-Chun, E-mail: xulichun@tyut.edu.cn; Song, Xian-Jiang; Yang, Zhi; Cao, Ling; Liu, Rui-Ping; Li, Xiu-Yan

    2015-01-01

    Highlights: • Hydrogenation and fluorination can passivate the metallic edge states of zPNRs. • The bandgap of each type of zPNRs decreases as the ribbon's width increases duo to the quantum confinement effect. • Two local configurations of passivated atoms can coexist in nanoribbons and affect the bandgap of narrow nanoribbons. • New passivation configuration can effectively reduce the effective mass of electrons. - Abstract: The edge passivation effect of phosphorene nanoribbons is systematically investigated using density functional theory. Hydrogen and fluorine atoms passivate the metallic edge states of nanoribbons and can open a bandgap up to 2.25 eV. The two configurations of passivated atoms can exist at two edges and affect the bandgap of narrow nanoribbons. The bandgap of each type of zPNRs decreases as the ribbon's width increases, which can be attributed to the quantum confinement effect. The new configuration, named C{sub b}, can effectively reduce the effective mass of electrons, which benefits the future design of phosphorene-based electronic devices.

  14. Fabrication of All-Solid-State Lithium-Ion Cells Using Three-Dimensionally Structured Solid Electrolyte Li7La3Zr2O12 Pellets

    International Nuclear Information System (INIS)

    Shoji, Mao; Munakata, Hirokazu; Kanamura, Kiyoshi

    2016-01-01

    All-solid-state lithium-ion batteries using Li + -ion conducting ceramic electrolytes have been focused on as attractive future batteries for electric vehicles and renewable energy conversion systems because high safety can be realized due to non-flammability of ceramic electrolytes. In addition, a higher volumetric energy density than that of current lithium-ion batteries is expected since the all-solid-state lithium-ion batteries can be made in bipolar cell configurations. However, the special ideas and techniques based on ceramic processing are required to construct the electrochemical interface for all-solid-state lithium-ion batteries since the battery development has been done so far based on liquid electrolyte system over 100 years. As one of the promising approaches to develop practical all-solid-state batteries, we have been focusing on three-dimensionally (3D) structured cell configurations such as an interdigitated combination of 3D pillars of cathode and anode, which can be realized by using solid electrolyte membranes with hole-array structures. The application of such kinds of 3D structures effectively increases the interface between solid electrode and solid electrolyte per unit volume, lowering the internal resistance of all-solid-state lithium-ion batteries. In this study, Li 6.25 Al 0.25 La 3 Zr 2 O 12 (LLZAl), which is a Al-doped Li 7 La 3 Zr 2 O 12 (LLZ) with Li + -ion conductivity of ~10 –4 S ⋅cm −1 at room temperature and high stability against lithium-metal, was used as a solid electrolyte, and its pellets with 700 μm depth holes in 700 μm × 700 μm area were fabricated to construct 3D-structured all-solid-state batteries with LiCoO 2 /LLZAl/lithium-metal configuration. It is expected that the LiCoO 2 –LLZAl interface is formed by point-to-point contact even when the LLZAl pellet with 3D hole-array structure is applied. Therefore, Li 3 BO 3 , which is a mechanically soft solid electrolyte with a low melting point at around 700

  15. Optimum design of band-gap beam structures

    DEFF Research Database (Denmark)

    Olhoff, Niels; Niu, Bin; Cheng, Gengdong

    2012-01-01

    The design of band-gap structures receives increasing attention for many applications in mitigation of undesirable vibration and noise emission levels. A band-gap structure usually consists of a periodic distribution of elastic materials or segments, where the propagation of waves is impeded...... or significantly suppressed for a range of external excitation frequencies. Maximization of the band-gap is therefore an obvious objective for optimum design. This problem is sometimes formulated by optimizing a parameterized design model which assumes multiple periodicity in the design. However, it is shown...... in the present paper that such an a priori assumption is not necessary since, in general, just the maximization of the gap between two consecutive natural frequencies leads to significant design periodicity. The aim of this paper is to maximize frequency gaps by shape optimization of transversely vibrating...

  16. Preparation of hydroxide ion conductive KOH–layered double hydroxide electrolytes for an all-solid-state iron–air secondary battery

    Directory of Open Access Journals (Sweden)

    Taku Tsuneishi

    2014-06-01

    Full Text Available Anion conductive solid electrolytes based on Mg–Al layered double hydroxide (LDH were prepared for application in an all-solid-state Fe–air battery. The ionic conductivity and the conducting ion species were evaluated from impedance and electromotive force measurements. The ion conductivity of LDH was markedly enhanced upon addition of KOH. The electromotive force in a water vapor concentration cell was similar to that of an anion-conducting polymer membrane. The KOH–LDH obtained was used as a hydroxide ion conductive electrolyte for all-solid-state Fe–air batteries. The cell performance of the Fe–air batteries was examined using a mixture of KOH–LDH and iron-oxide-supported carbon as the negative electrode.

  17. All-solid-state ultraviolet 330 nm laser from frequency-doubling of Nd:YLF red laser in CsB3O5

    International Nuclear Information System (INIS)

    Chen, Ming; Wang, Zhi-chao; Wang, Bao-shan; Yang, Feng; Zhang, Guo-chun; Zhang, Shen-jin; Zhang, Feng-feng; Zhang, Xiao-wen; Zong, Nan; Wang, Zhi-min; Bo, Yong; Peng, Qin-jun; Cui, Da-fu; Wu, Yi-cheng; Xu, Zu-yan

    2016-01-01

    We demonstrate an ultraviolet (UV) 330 nm laser from second-harmonic generation (SHG) of an all-solid-state Nd:YLF red laser in a CsB 3 O 5 (CBO) crystal for the first time, to our best knowledge. Under an input power of 4.8 W at 660 nm, a maximum average output power of 330 nm laser was obtained to be 1.28 W, corresponding to a frequency conversion efficiency of about 26.7%.

  18. NiCo2O4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

    KAUST Repository

    Wang, Renqi

    2016-03-04

    Ternary transition metal oxides such as NiCo2O4 show great promise as supercapacitor electrode materials. However, the unsatisfactory rate performance of NiCo2O4 may prove to be a major hurdle to its commercial usage. Herein, we report the development of NiCo2O4@TiN core–shell nanostructures for all-solid-state supercapacitors with significantly enhanced rate capability. We demonstrate that a thin layer of TiN conformally grown by atomic layer deposition (ALD) on NiCo2O4 nanofiber arrays plays a key role in improving their electrical conductivity, mechanical stability, and rate performance. Fabricated using the hybrid NiCo2O4@TiN electrodes, the symmetric all-solid-state supercapacitor exhibited an impressive stack power density of 58.205 mW cm−3 at a stack energy density of 0.061 mWh cm−3. To the best of our knowledge, these values are the highest of any NiCo2O4-based all-solid-state supercapacitor reported. Additionally, the resulting NiCo2O4@TiN all-solid-state device displayed outstanding cycling stability by retaining 70% of its original capacitance after 20,000 cycles at a high current density of 10 mA cm−2. These results illustrate the promise of ALD-assisted hybrid NiCo2O4@TiN electrodes for sustainable and integrated energy storage applications.

  19. NiCo2O4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

    KAUST Repository

    Wang, Renqi; Xia, Chuan; Wei, Nini; Alshareef, Husam N.

    2016-01-01

    Ternary transition metal oxides such as NiCo2O4 show great promise as supercapacitor electrode materials. However, the unsatisfactory rate performance of NiCo2O4 may prove to be a major hurdle to its commercial usage. Herein, we report the development of NiCo2O4@TiN core–shell nanostructures for all-solid-state supercapacitors with significantly enhanced rate capability. We demonstrate that a thin layer of TiN conformally grown by atomic layer deposition (ALD) on NiCo2O4 nanofiber arrays plays a key role in improving their electrical conductivity, mechanical stability, and rate performance. Fabricated using the hybrid NiCo2O4@TiN electrodes, the symmetric all-solid-state supercapacitor exhibited an impressive stack power density of 58.205 mW cm−3 at a stack energy density of 0.061 mWh cm−3. To the best of our knowledge, these values are the highest of any NiCo2O4-based all-solid-state supercapacitor reported. Additionally, the resulting NiCo2O4@TiN all-solid-state device displayed outstanding cycling stability by retaining 70% of its original capacitance after 20,000 cycles at a high current density of 10 mA cm−2. These results illustrate the promise of ALD-assisted hybrid NiCo2O4@TiN electrodes for sustainable and integrated energy storage applications.

  20. Electrochemical performance of all-solid-state lithium batteries using inorganic lithium garnets particulate reinforced PEO/LiClO4 electrolyte

    International Nuclear Information System (INIS)

    Cheng, Samson Ho-Sum; He, Kang-Qiang; Liu, Ying; Zha, Jun-Wei; Kamruzzaman, Md; Ma, Robin Lok-Wang; Dang, Zhi-Min; Li, Robert K.Y.; Chung, C.Y.

    2017-01-01

    All-solid-state batteries are proposed to have ultimate safety and higher power and energy densities over conventional lithium ion batteries with liquid electrolytes. The Li ion conductivity and interfacial resistance between electrolyte and electrodes are the major bottleneck of the development of all-solid-state batteries for practical uses. Here, we reported a novel composite electrolyte which is composed of uniform distributed Li ion conducting Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) fillers in PEO/LiClO 4 matrix. The EO:Li + ratio of 15:1 is being used to achieve lower interfacial resistance between electrolyte and electrodes through the melting process. The composite electrolyte is fabricated by simple solution casting method, which is more advantageous comparing with high temperature sintering or sol-gel method used in the fabrication of ceramic electrolytes. The composite electrolyte exhibits good Li ion conductivity of 4.8 × 10 −4 Scm −1 at 60 °C and excellent interfacial stability against Li metal. The all-solid-state lithium battery using this composite electrolyte shows a specific capacity of 140mAhg −1 and an unprecedentedly high capacity retention of 83% after 500 cycles at 60 °C and the rate of 1C. It is concluded that good electrode/electrolyte interfacial stability and contact as well as fast Li ion conductivity obtained by the addition of active garnet particulates to PEO/LiClO 4 matrix are essential criteria for good charge/discharge performance of all-solid-state lithium batteries.

  1. All-solid-state thin film battery based on well-aligned slanted LiCoO{sub 2} nanowires fabricated by glancing angle deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Miyoung [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Seunghwan [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Daehee [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Joosun, E-mail: joosun@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Moon, Jooho, E-mail: jmoon@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2017-08-01

    Graphical abstract: We successfully fabricated well-aligned slanted LiCoO{sub 2} nanowires as a one-dimensional nanostructured cathode by glancing angle deposition to enhance the electrochemical performance of all-solid-state thin film batteries. - Highlights: • Well-aligned slanted LiCoO{sub 2} nanowires are fabricated by glancing angle deposition. • One-dimensional nanostructured LiCoO{sub 2} cathode enlarges the contact area. • All-solid-state thin film battery exhibits enhances rate capability and cycling stability. - Abstract: We fabricated all-solid-state thin film batteries based on well-aligned slanted LiCoO{sub 2} nanowires by glancing angle deposition, as a facile template-free method in order to increase the electrochemically active site, i.e., the contact area between the solid electrolyte and the electrode. A highly porous thin film composed of well-separated slanted LiCoO{sub 2} nanowires not only facilitates the penetration of solid electrolyte phase into the cathode, but also alleviates the thermally and mechanically induced stresses during post-annealing and electrochemical cycling. The all-solid-state thin film battery based on the well-aligned slanted LiCoO{sub 2} nanowires, whose contact area between electrolyte and electrode was three times as high as that of a dense thin film, could provide additional migration pathways for lithium ion diffusion due to the enlarged reaction sites. This resulted in enhanced electrochemical kinetics, thereby leading to better rate capability and long-term cyclic stability as compared to the dense LiCoO{sub 2} thin film.

  2. Experimental Methods for Implementing Graphene Contacts to Finite Bandgap Semiconductors

    DEFF Research Database (Denmark)

    Meyer-Holdt, Jakob

    Present Ph.D. thesis describes my work on implanting graphene as electrical contact to finite bandgap semiconductors. Different transistor architectures, types of graphene and finite bandgap semiconductors have been employed. The device planned from the beginning of my Ph.D. fellowship...... contacts to semiconductor nanowires, more specifically, epitaxially grown InAs nanowires. First, we tried a top down method where CVD graphene was deposited on substrate supported InAs nanowires followed by selective graphene ashing to define graphene electrodes. While electrical contact between...

  3. CONFERENCE: Photon-photon collisions

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists

  4. All-solid, flexible solar textiles based on dye-sensitized solar cells with ZnO nanorod arrays on stainless steel wires

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Youngjin [Department of Clothing and Textiles, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, Jung Tae; Koh, Jong Kwan [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Jong Hak, E-mail: jonghak@yonsei.ac.kr [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Eunae, E-mail: eakim@yonsei.ac.kr [Department of Clothing and Textiles, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

    2013-10-01

    Highlights: • All-solid, flexible solar textile fabricated with DSSCs is demonstrated. • DSSCs woven into a satin structure and transparent PET film are used. • Solar textile showed a high efficiency of 2.57%. -- Abstract: An all-solid, flexible solar textile fabricated with dye-sensitized solar cells (DSSCs) woven into a satin structure and transparent poly(ethylene terephthalate) (PET) film was demonstrated. A ZnO nanorod (NR) vertically grown from fiber-type conductive stainless steel (SS) wire was utilized as a photoelectrode, and a Pt-coated SS wire was used as a counter electrode. A graft copolymer, i.e. poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) was synthesized via atom transfer radical polymerization (ATRP) and used as a solid electrolyte. The conditions for the growth of ZnO NR and sufficient dye loading were investigated to improve cell performance. The adhesion of PET films to DSSCs resulted in physical stability improvements without cell performance loss. The solar textile with 10 × 10 wires exhibited an energy conversion efficiency of 2.57% with a short circuit current density of 20.2 mA/cm{sup 2} at 100 mW/cm{sup 2} illumination, which is the greatest account of an all-solid, ZnO-based flexible solar textile. DSSC textiles with woven structures are applicable to large-area, roll-to-roll processes.

  5. Defect modes in silver-doped photonic crystals made by holography using dichromated gelatin

    Science.gov (United States)

    Dai, Rui; Chen, Shujing; Ren, Zhi; Wang, Zhaona; Liu, Dahe

    2012-10-01

    The defect mode in silver-doped photonic crystals is investigated. 1D and 3D photonic crystals were made by holography using dichromated gelatin mixed with silver nitrate. By controlling the concentration of the silver nitrate, the defect mode was observed in the bandgaps of the holographic photonic crystals. The numerical simulations were made, and the results showed the consistency with the experimental observations.

  6. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  7. Fabrication of photonic amorphous diamonds for terahertz-wave applications

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, Yuichiro; Abe, Hiroyuki; Kamimura, Yasushi; Edagawa, Keiichi, E-mail: edagawa@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

    2016-05-09

    A recently proposed photonic bandgap material, named “photonic amorphous diamond” (PAD), was fabricated in a terahertz regime, and its terahertz-wave propagation properties were investigated. The PAD structure was fabricated from acrylic resin mixed with alumina powder, using laser lithographic, micro-additive manufacturing technique. After fabrication, the resulting structure was dewaxed and sintered. The formation of a photonic bandgap at around 0.45 THz was demonstrated by terahertz time-domain spectroscopy. Reflecting the disordered nature of the random network structure, diffusive terahertz-wave propagation was observed in the passbands; the scattering mean-free path decreased as the frequency approached the band edge. The mean-free paths evaluated at the band edges were close to the Ioffe-Regel threshold value for wave localization.

  8. New Light-Harvesting Materials Using Accurate and Efficient Bandgap Calculations

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Hüser, Falco; Pandey, Mohnish

    2014-01-01

    Electronic bandgap calculations are presented for 2400 experimentally known materials from the Materials Project database and the bandgaps, obtained with different types of functionals within density functional theory and (partial) self-consistent GW approximation, are compared for 20 randomly...

  9. Bandgap Opening in Graphene Induced by Patterned Hydrogen Adsorption

    DEFF Research Database (Denmark)

    Balog, Richard; Jørgensen, Bjarke; Nilsson, Louis

    2010-01-01

    fermions, and graphene shows ballistic charge transport, turning it into an ideal material for circuit fabrication. However, graphene lacks a bandgap around the Fermi level, which is the defining concept for semiconductor materials and essential for controlling the conductivity by electronic means. Theory...

  10. Automating Energy Bandgap Measurements in Semiconductors Using LabVIEW

    Science.gov (United States)

    Garg, Amit; Sharma, Reena; Dhingra, Vishal

    2010-01-01

    In this paper, we report the development of an automated system for energy bandgap and resistivity measurement of a semiconductor sample using Four-Probe method for use in the undergraduate laboratory of Physics and Electronics students. The automated data acquisition and analysis system has been developed using National Instruments USB-6008 DAQ…

  11. High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

    Science.gov (United States)

    Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

    2002-01-01

    It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

  12. Design for maximum band-gaps in beam structures

    DEFF Research Database (Denmark)

    Olhoff, Niels; Niu, Bin; Cheng, Gengdong

    2012-01-01

    This paper aims to extend earlier optimum design results for transversely vibrating Bernoulli-Euler beams by determining new optimum band-gap beam structures for (i) different combinations of classical boundary conditions, (ii) much larger values of the orders n and n-1 of adjacent upper and lower...

  13. Advances in wide bandgap SiC for optoelectronics

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini

    2014-01-01

    Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication...

  14. CMOS bandgap references and temperature sensors and their applications

    NARCIS (Netherlands)

    Wang, G.

    2005-01-01

    Two main parts have been presented in this thesis: device characterization and circuit. In integrated bandgap references and temperature sensors, the IC(VBE, characteristics of bipolar transistors are used to generate the basic signals with high accuracy. To investigate the possibilities to

  15. Optimal design of tunable phononic bandgap plates under equibiaxial stretch

    International Nuclear Information System (INIS)

    Hedayatrasa, Saeid; Abhary, Kazem; Uddin, M S; Guest, James K

    2016-01-01

    Design and application of phononic crystal (PhCr) acoustic metamaterials has been a topic with tremendous growth of interest in the last decade due to their promising capabilities to manipulate acoustic and elastodynamic waves. Phononic controllability of waves through a particular PhCr is limited only to the spectrums located within its fixed bandgap frequency. Hence the ability to tune a PhCr is desired to add functionality over its variable bandgap frequency or for switchability. Deformation induced bandgap tunability of elastomeric PhCr solids and plates with prescribed topology have been studied by other researchers. Principally the internal stress state and distorted geometry of a deformed phononic crystal plate (PhP) changes its effective stiffness and leads to deformation induced tunability of resultant modal band structure. Thus the microstructural topology of a PhP can be altered so that specific tunability features are met through prescribed deformation. In the present study novel tunable PhPs of this kind with optimized bandgap efficiency-tunability of guided waves are computationally explored and evaluated. Low loss transmission of guided waves throughout thin walled structures makes them ideal for fabrication of low loss ultrasound devices and structural health monitoring purposes. Various tunability targets are defined to enhance or degrade complete bandgaps of plate waves through macroscopic tensile deformation. Elastomeric hyperelastic material is considered which enables recoverable micromechanical deformation under tuning finite stretch. Phononic tunability through stable deformation of phononic lattice is specifically required and so any topology showing buckling instability under assumed deformation is disregarded. Nondominated sorting genetic algorithm (GA) NSGA-II is adopted for evolutionary multiobjective topology optimization of hypothesized tunable PhP with square symmetric unit-cell and relevant topologies are analyzed through finite

  16. Coaxial CoMoO4 nanowire arrays with chemically integrated conductive coating for high-performance flexible all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Chen, Yaping; Liu, Borui; Liu, Qi; Wang, Jun; Li, Zhanshuang; Jing, Xiaoyan; Liu, Lianhe

    2015-09-01

    Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm-2 at a current density of 2 mA cm-2, which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm-2. An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm-2) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg-1 (3.522 mW h cm-3), demonstrating great potential for practical applications in flexible energy storage electronics.Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on

  17. Polychromatic photons

    DEFF Research Database (Denmark)

    Keller, Ole

    2002-01-01

    train quantum electrodynamics. A brief description of particle (photon) position operators is given, and it is shown that photons usually are only algebraically confined in an emission process. Finally, it is demonstrated that the profile of the birth domain of a radio-frequency photon emitted...

  18. Assembling nitrogen and oxygen co-doped graphene quantum dots onto hierarchical carbon networks for all-solid-state flexible supercapacitors

    International Nuclear Information System (INIS)

    Li, Zhen; Li, Yanfeng; Wang, Liang; Cao, Ling; Liu, Xiang; Chen, Zhiwen; Pan, Dengyu; Wu, Minghong

    2017-01-01

    Highlights: • The all-carbon ternary flexible electrodes have been fabricated by the electrode deposition of nitrogen and oxygen co-doped single-crystalline GQDs. • The flexible electrodes deliver ultrahigh specific capacitance (461 mF cm"−"2) by inducing a high concentration of active nitrogen and oxygen at edge. • Symmetrical N-O-GQD/CNT/CC all-solid-state flexible supercapacitors offer energy density up to 32 μWh cm"−"2 and demonstrate the good stability, high flexibility, and folding ability under different deformations. • Nitrogen and oxygen co-doped GQDs can function as a highly active, solution-processable pseudocapacitive materials applicable to high-performance supercapacitors. - Abstract: We present a novel approach for hierarchical fabrication of high-performance, all-solid-state, flexible supercapacitors from environmentally friendly all-carbon materials. Three-dimensional carbon nanotube/carbon cloth network (CNT/CC) is used as a conductive, flexible and free-standing scaffold for the electro-deposition of highly N/O co-doped graphene quantum dots to form the high-activity, all-carbon electrodes. The hierarchical structure of the CNT/CC network with high electrical conductivity and high surface area provides improved conductive pathways for the efficient activation of GQDs with high pseudocapacitance and electrical double layer capacitance. The obtained N-O-GQD/CNT/CC electrodes for all-solid-state flexible supercapacitors exhibit an ultrahigh areal capacitance of up to 461 mF cm"−"2 at a current density of 0.5 mA cm"−"2, while keeping high rate and cyclic performances. This work highlights the great potential of highly active GQDs in the construction of high-performance flexible energy-storage devices.

  19. Flexible Fe2O3 and V2O5 nanofibers as binder-free electrodes for high-performance all-solid-state asymmetric supercapacitors.

    Science.gov (United States)

    Jiang, He; Niu, Hao; Yang, Xue; Sun, Zhiqin; Li, Fuzhi; Wang, Qian; Qu, Fengyu

    2018-04-16

    Flexible highly porous Fe2O3 and V2O5 nanofibers are synthesized by a facile electrospinning method followed by calcination treatment and directly used as binder-free electrodes for high-performance supercapacitors. These Fe2O3 and V2O5 nanofibers interconnect with each other and construct three-dimensional hierarchical porous films with high specific surface area. Benefiting from the unique structural features, the intriguing binder-free Fe2O3 and V2O5 porous nanofiber electrodes possess high specific capacitance of 255 F g-1 and 256 F g-1 at 2 mV s-1 in 1 M Na2SO4 electrolyte, respectively. An all-solid-state asymmetric supercapacitor is fabricated using Fe2O3 and V2O5 nanofibers as negative and positive electrodes, respectively, and the all-solid-state asymmetric supercapacitor can be operated up to 1.8 V attributed to the wide and opposite potential window of both electrodes. The assembled all-solid-state asymmetric supercapacitor achieves a high energy density up to 32.2 Wh kg-1 at an average power density of 128.7 W kg-1 as well as excellent cycling stability and power capability. The effective and facile synthesis method and superior electrochemical performance provided in this work make electrospun Fe2O3 and V2O5 nanofibers promising electrode materials for high performance asymmetric supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High ion conductive Sb2O5-doped β-Li3PS4 with excellent stability against Li for all-solid-state lithium batteries

    Science.gov (United States)

    Xie, Dongjiu; Chen, Shaojie; Zhang, Zhihua; Ren, Jie; Yao, Lili; Wu, Linbin; Yao, Xiayin; Xu, Xiaoxiong

    2018-06-01

    The combination of high conductivity and good stability against Li is not easy to achieve for solid electrolytes, hindering the development of high energy solid-state batteries. In this study, doped electrolytes of Li3P1-xSbxS4-2.5xO2.5x are successfully prepared via the high energy ball milling and subsequent heat treatment. Plenty of techniques like XRD, Raman, SEM, EDS and TEM are utilized to characterize the crystal structures, particle sizes, and morphologies of the glass-ceramic electrolytes. Among them, the Li3P0.98Sb0.02S3.95O0.05 (x = 0.02) exhibits the highest ionic conductivity (∼1.08 mS cm-1) at room temperature with an excellent stability against lithium. In addition, all-solid-state lithium batteries are assembled with LiCoO2 as cathode, Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 as the bi-layer electrolyte, and lithium as anode. The constructed solid-state batteries delivers a high initial discharge capacity of 133 mAh g-1 at 0.1C in the range of 3.0-4.3 V vs. Li/Li+ at room temperature, and shows a capacity retention of 78.6% after 50 cycles. Most importantly, the all-solid-state lithium batteries with the Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 electrolyte can be workable even at -10 °C. This study provides a promising electrolyte with the improved conductivity and stability against Li for the application of all-solid-state lithium batteries.

  1. Co3O4/MnO2/Hierarchically Porous Carbon as Superior Bifunctional Electrodes for Liquid and All-Solid-State Rechargeable Zinc-Air Batteries.

    Science.gov (United States)

    Li, Xuemei; Dong, Fang; Xu, Nengneng; Zhang, Tao; Li, Kaixi; Qiao, Jinli

    2018-05-09

    The design of efficient, durable, and affordable catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is very indispensable in liquid-type and flexible all-solid-state zinc-air batteries. Herein, we present a high-performance bifunctional catalyst with cobalt and manganese oxides supported on porous carbon (Co 3 O 4 /MnO 2 /PQ-7). The optimized Co 3 O 4 /MnO 2 /PQ-7 exhibited a comparable ORR performance with commercial Pt/C and a more superior OER performance than all of the other prepared catalysts, including commercial Pt/C. When applied to practical aqueous (6.0 M KOH) zinc-air batteries, the Co 3 O 4 /MnO 2 /porous carbon hybrid catalysts exhibited exceptional performance, such as a maximum discharge peak power density as high as 257 mW cm -2 and the most stable charge-discharge durability over 50 h with negligible deactivation to date. More importantly, a series of flexible all-solid-state zinc-air batteries can be fabricated by the Co 3 O 4 /MnO 2 /porous carbon with a layer-by-layer method. The optimal catalyst (Co 3 O 4 /MnO 2 /PQ-7) exhibited an excellent peak power density of 45 mW cm -2 . The discharge potentials almost remained unchanged for 6 h at 5 mA cm -2 and possessed a long cycle life (2.5 h@5 mA cm -2 ). These results make the optimized Co 3 O 4 /MnO 2 /PQ-7 a promising cathode candidate for both liquid-type and flexible all-solid-state zinc-air batteries.

  2. Reduced graphene oxide-wrapped MoO3 composites prepared by using metal-organic frameworks as precursor for all-solid-state flexible supercapacitors.

    Science.gov (United States)

    Cao, Xiehong; Zheng, Bing; Shi, Wenhui; Yang, Jian; Fan, Zhanxi; Luo, Zhimin; Rui, Xianhong; Chen, Bo; Yan, Qingyu; Zhang, Hua

    2015-08-26

    Reduced graphene oxide-wrapped MoO3M (rGO/MoO3 ) is prepared by a novel and simple method that is developed by using a metal-organic framework as the precursor. After a two-step annealing process, the obtained rGO/MoO3 composite is used for a high-performance supercapacitor electrode. Moreover, an all-solid-state flexible supercapacitor is fabricated based on the rGO/MoO3 composite, which shows stable performance under different bending states. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. NiCo_2O_4@TiN Core-shell Electrodes through Conformal Atomic Layer Deposition for All-solid-state Supercapacitors

    International Nuclear Information System (INIS)

    Wang, Ruiqi; Xia, Chuan; Wei, Nini; Alshareef, Husam N.

    2016-01-01

    Highlights: • NiCo_2O_4 nanostructures are prepared via a simple hydrothermal method. • Outer shell of TiN is then grown through conformal atomic layer deposition. • Electrodes exhibit significantly enhanced rate capability with TiN coating. • Solid-state polymer electrolyte is employed to improve cycling stability. • Full devices show a stack power density of 58.205 mW cm"−"3 at 0.061 mWh cm"−"3. - Abstract: Ternary transition metal oxides such as NiCo_2O_4 show great potential as supercapacitor electrode materials. However, the unsatisfactory rate performance of NiCo_2O_4 may prove to be a major hurdle to its commercial usage. Herein, we report the development of NiCo_2O_4@TiN core–shell nanostructures for all-solid-state supercapacitors with significantly enhanced rate capability. We demonstrate that a thin layer of TiN conformally grown by atomic layer deposition (ALD) on NiCo_2O_4 nanofiber arrays plays a key role in improving their electrical conductivity, mechanical stability, and rate performance. Fabricated using the hybrid NiCo_2O_4@TiN electrodes, the symmetric all-solid-state supercapacitor exhibited an impressive stack power density of 58.205 mW cm"−"3 at a stack energy density of 0.061 mWh cm"−"3. To the best of our knowledge, these values are the highest of any NiCo_2O_4-based all-solid-state supercapacitor reported. Additionally, the resulting NiCo_2O_4@TiN all-solid-state device displayed outstanding cycling stability by retaining 70% of its original capacitance after 20,000 cycles at a high current density of 10 mA cm"−"2. These results illustrate the promise of ALD-assisted hybrid NiCo_2O_4@TiN electrodes within sustainable and integrated energy storage applications.

  4. Single-Photon Source for Quantum Information Based on Single Dye Molecule Fluorescence in Liquid Crystal Host

    International Nuclear Information System (INIS)

    Lukishova, S.G.; Knox, R.P.; Freivald, P.; McNamara, A.; Boyd, R.W.; Stroud, Jr. C.R.; Schmid, A.W.; Marshall, K.L.

    2006-01-01

    This paper describes a new application for liquid crystals: quantum information technology. A deterministically polarized single-photon source that efficiently produces photons exhibiting antibunching is a pivotal hardware element in absolutely secure quantum communication. Planar-aligned nematic liquid crystal hosts deterministically align the single dye molecules which produce deterministically polarized single (antibunched) photons. In addition, 1-D photonic bandgap cholesteric liquid crystals will increase single-photon source efficiency. The experiments and challenges in the observation of deterministically polarized fluorescence from single dye molecules in planar-aligned glassy nematic-liquid-crystal oligomer as well as photon antibunching in glassy cholesteric oligomer are described for the first time

  5. Extended-Range Ultrarefractive 1D Photonic Crystal Prisms

    Science.gov (United States)

    Ting, David Z.

    2007-01-01

    A proposal has been made to exploit the special wavelength-dispersive characteristics of devices of the type described in One-Dimensional Photonic Crystal Superprisms (NPO-30232) NASA Tech Briefs, Vol. 29, No. 4 (April 2005), page 10a. A photonic crystal is an optical component that has a periodic structure comprising two dielectric materials with high dielectric contrast (e.g., a semiconductor and air), with geometrical feature sizes comparable to or smaller than light wavelengths of interest. Experimental superprisms have been realized as photonic crystals having three-dimensional (3D) structures comprising regions of amorphous Si alternating with regions of SiO2, fabricated in a complex process that included sputtering. A photonic crystal of the type to be exploited according to the present proposal is said to be one-dimensional (1D) because its contrasting dielectric materials would be stacked in parallel planar layers; in other words, there would be spatial periodicity in one dimension only. The processes of designing and fabricating 1D photonic crystal superprisms would be simpler and, hence, would cost less than do those for 3D photonic crystal superprisms. As in 3D structures, 1D photonic crystals may be used in applications such as wavelength-division multiplexing. In the extended-range configuration, it is also suitable for spectrometry applications. As an engineered structure or artificially engineered material, a photonic crystal can exhibit optical properties not commonly found in natural substances. Prior research had revealed several classes of photonic crystal structures for which the propagation of electromagnetic radiation is forbidden in certain frequency ranges, denoted photonic bandgaps. It had also been found that in narrow frequency bands just outside the photonic bandgaps, the angular wavelength dispersion of electromagnetic waves propagating in photonic crystal superprisms is much stronger than is the angular wavelength dispersion obtained

  6. S-containing copolymer as cathode material in poly(ethylene oxide)-based all-solid-state Li-S batteries

    Science.gov (United States)

    Gracia, Ismael; Ben Youcef, Hicham; Judez, Xabier; Oteo, Uxue; Zhang, Heng; Li, Chunmei; Rodriguez-Martinez, Lide M.; Armand, Michel

    2018-06-01

    Inverse vulcanization copolymers (p(S-DVB)) from the radical polymerization of elemental sulfur and divinylbenzene (DVB) have been studied as cathode active materials in poly(ethylene oxide) (PEO)-based all-solid-state Li-S cells. The Li-S cell comprising the optimized p(S-DVB) cathode (80:20 w/w S/DVB ratio) and lithium bis(fluorosulfonyl)imide/PEO (LiFSI/PEO) electrolyte shows high specific capacity (ca. 800 mAh g-1) and high Coulombic efficiency for 50 cycles. Most importantly, polysulfide (PS) shuttle is highly mitigated due to the strong interactions of PS species with polymer backbone in p(S-DVB). This is demonstrated by the stable cycling of the p(S-DVB)-based cell using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/PEO electrolyte, where successful charging cannot be achieved even at the first cycle with plain elemental S-based cathode material due to the severe PS shuttle phenomenon. These results suggest that inverse vulcanization copolymers are promising alternatives to elemental sulfur for enhancing the electrochemical performance of PEO-based all-solid-state Li-S cells.

  7. Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

    Science.gov (United States)

    de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

    2014-08-01

    The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

  8. Supercontinuum generation covering the entire 0.4-5 µm transmission window in a tapered ultra-high numerical aperture all-solid fluorotellurite fiber

    Science.gov (United States)

    Jia, Z. X.; Yao, C. F.; Jia, S. J.; Wang, F.; Wang, S. B.; Zhao, Z. P.; Liao, M. S.; Qin, G. S.; Hu, L. L.; Ohishi, Y.; Qin, W. P.

    2018-02-01

    Enormous efforts have been made to realize supercontinuum (SC) generation covering the entire transmission window of fiber materials for their wide applications in many fields. Here we demonstrate ultra-broadband SC generation from 400 to 5140 nm in a tapered ultra-high numerical aperture (NA) all-solid fluorotellurite fiber pumped by a 1560 nm mode-locked fiber laser. The fluorotellurite fibers are fabricated using a rod-in-tube method. The core and cladding materials are TeO2-BaF2-Y2O3- and TeO2-modified fluoroaluminate glasses, respectively, which have large refractive index contrast and similar thermal expansion coefficients and softening temperatures. The NA at 3200 nm of the fluorotellurite fiber is about 1.11. Furthermore, tapered fluorotellurite fibers are prepared using an elongation machine. SC generation covering the entire 0.4-5 µm transmission window is achieved in a tapered fluorotellurite fiber for a pumping peak power of ~10.5 kW through synergetic control of dispersion, nonlinearity, confinement loss and other unexpected effects (e.g. the attachment of dust or water to the surface of the fiber core) of the fiber. Our results show that tapered ultra-high NA all-solid soft glass fibers have a potential for generating SC light covering their entire transmission window.

  9. Wet-process Fabrication of Low-cost All-solid Wire-shaped Solar Cells on Manganese-plated Electrodes

    International Nuclear Information System (INIS)

    Fan, Xing; Zhang, Xiaoying; Zhang, Nannan; Cheng, Li; Du, Jun; Tao, Changyuan

    2015-01-01

    Highlights: • All-solid wire-shaped flexible solar cells are firstly assembled on low-cost Mn-plated fibers. • Energy efficiency improved by >27% after coating a layer of Mn on various substrates. • The cell is fabricated via wet process under low temperature and mild pH conditions. • Stable flexible solar cells are realized on lightweight and low-cost polymer fiber. - Abstract: All-solid wire-shaped flexible solar cells are assembled for the first time on low-cost Mn-plated wires through wet-process fabrication under low temperature and mild pH conditions. With a price cheap as the steel, metal Mn can be easily plated on almost any substrates, and evidently promote the photovoltaic efficiency of wire-shaped solar cells on various traditional metal wire substrates, such as Fe and Ti, by 27% and 65%, respectively. Flexible solar cell with much lower cost and weight is assembled on Mn-plated polymer substrate, and is still capable of giving better performance than that on Fe or Ti substrate. Both its mechanical and chemical stability are good for future weaving applications. Owing to the wire-type structure, such low-cost metals as Mn, which are traditionally regarded as unsuitable for solar cells, may provide new opportunities for highly efficient solar cells

  10. The approach of in-situ doping ion conductor fabricated with the cathodic arc plasma for all-solid-state electrochromic devices

    Directory of Open Access Journals (Sweden)

    Min-Chuan Wang

    2018-01-01

    Full Text Available The all-solid-state electrochromic device (ECD with the one substrate structure fabricated by the reactive dc magnetron sputtering (DCMS and in-situ doping cathodic vacuum arc plasma (CVAP technology has been developed. The electrochromic (EC layer and ion conductor layer were deposited by reactive DCMS and CVAP technology, respectively. The in-situ doping ion conductor Ta2O5 deposited by the CVAP technology has provided the better material structure for ion transportation and showed about 2 times ion conductivity than the external doping process. The all-solid-state ECD with the in-situ doping CVAP ion conductor layer has demonstrated a maximum transmittance variation (ΔT of 71% at 550 nm, and a faster switching speed. The lower production cost and higher process stability could be achieved by the application of in-situ doping CVAP technology without breaking the vacuum process. Furthermore, the ion doping process with the reuse of energy during the CVAP process is not only decreasing the process steps, but also reducing the process energy consumption.

  11. Passive band-gap reconfiguration born from bifurcation asymmetry.

    Science.gov (United States)

    Bernard, Brian P; Mann, Brian P

    2013-11-01

    Current periodic structures are constrained to have fixed energy transmission behavior unless active control or component replacement is used to alter their wave propagation characteristics. The introduction of nonlinearity to generate multiple stable equilibria is an alternative strategy for realizing distinct energy propagation behaviors. We investigate the creation of a reconfigurable band-gap system by implementing passive switching between multiple stable states of equilibrium, to alter the level of energy attenuation in response to environmental stimuli. The ability to avoid potentially catastrophic loads is demonstrated by tailoring the bandpass and band-gap regions to coalesce for two stable equilibria and varying an external load parameter to trigger a bifurcation. The proposed phenomenon could be utilized in remote or autonomous applications where component modifications and active control are impractical.

  12. Direct bandgap silicon: tensile-strained silicon nanocrystals

    Czech Academy of Sciences Publication Activity Database

    Kůsová, Kateřina; Hapala, Prokop; Valenta, J.; Jelínek, Pavel; Cibulka, Ondřej; Ondič, Lukáš; Pelant, Ivan

    2014-01-01

    Roč. 1, č. 2 (2014), "1300042-1"-"1300042-9" ISSN 2196-7350 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GPP204/12/P235; GA ČR GAP204/10/0952 Institutional support: RVO:68378271 Keywords : silicon nanocrystals * badstructure * light emission * direct bandgap * surface capping Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Ultrasonic bandgaps in 3D-printed periodic ceramic microlattices

    Czech Academy of Sciences Publication Activity Database

    Kruisová, Alena; Ševčík, Martin; Seiner, Hanuš; Sedlák, Petr; Román-Manso, B.; Miranzo, P.; Belmonte, M.; Landa, Michal

    January (2018), s. 91-100 ISSN 0041-624X R&D Projects: GA ČR GA17-01618S Institutional support: RVO:61388998 Keywords : phononic crystals * ceramic s * additive manufacturing * bandgaps * wave propagation * finite elements method Subject RIV: BI - Acoustics OBOR OECD: Applied mechanics Impact factor: 2.327, year: 2016 http://dx.doi.org/10.1016/j.ultras.2017.07.017

  14. Recent Advances in Wide-Bandgap Photovoltaic Polymers.

    Science.gov (United States)

    Cai, Yunhao; Huo, Lijun; Sun, Yanming

    2017-06-01

    The past decade has witnessed significant advances in the field of organic solar cells (OSCs). Ongoing improvements in the power conversion efficiency of OSCs have been achieved, which were mainly attributed to the design and synthesis of novel conjugated polymers with different architectures and functional moieties. Among various conjugated polymers, the development of wide-bandgap (WBG) polymers has received less attention than that of low-bandgap and medium-bandgap polymers. Here, we briefly summarize recent advances in WBG polymers and their applications in organic photovoltaic (PV) devices, such as tandem, ternary, and non-fullerene solar cells. Addtionally, we also dissuss the application of high open-circuit voltage tandem solar cells in PV-driven electrochemical water dissociation. We mainly focus on the molecular design strategies, the structure-property correlations, and the photovoltaic performance of these WBG polymers. Finally, we extract empirical regularities and provide invigorating perspectives on the future development of WBG photovoltaic materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A Direct Bandgap Copper-Antimony Halide Perovskite.

    Science.gov (United States)

    Vargas, Brenda; Ramos, Estrella; Pérez-Gutiérrez, Enrique; Alonso, Juan Carlos; Solis-Ibarra, Diego

    2017-07-12

    Since the establishment of perovskite solar cells (PSCs), there has been an intense search for alternative materials to replace lead and improve their stability toward moisture and light. As single-metal perovskite structures have yielded unsatisfactory performances, an alternative is the use of double perovskites that incorporate a combination of metals. To this day, only a handful of these compounds have been synthesized, but most of them have indirect bandgaps and/or do not have bandgaps energies well-suited for photovoltaic applications. Here we report the synthesis and characterization of a unique mixed metal ⟨111⟩-oriented layered perovskite, Cs 4 CuSb 2 Cl 12 (1), that incorporates Cu 2+ and Sb 3+ into layers that are three octahedra thick (n = 3). In addition to being made of abundant and nontoxic elements, we show that this material behaves as a semiconductor with a direct bandgap of 1.0 eV and its conductivity is 1 order of magnitude greater than that of MAPbI 3 (MA = methylammonium). Furthermore, 1 has high photo- and thermal-stability and is tolerant to humidity. We conclude that 1 is a promising material for photovoltaic applications and represents a new type of layered perovskite structure that incorporates metals in 2+ and 3+ oxidation states, thus significantly widening the possible combinations of metals to replace lead in PSCs.

  16. Bandgap tunability at single-layer molybdenum disulphide grain boundaries

    KAUST Repository

    Huang, Yu Li

    2015-02-17

    Two-dimensional transition metal dichalcogenides have emerged as a new class of semiconductor materials with novel electronic and optical properties of interest to future nanoelectronics technology. Single-layer molybdenum disulphide, which represents a prototype two-dimensional transition metal dichalcogenide, has an electronic bandgap that increases with decreasing layer thickness. Using high-resolution scanning tunnelling microscopy and spectroscopy, we measure the apparent quasiparticle energy gap to be 2.40±0.05 eV for single-layer, 2.10±0.05 eV for bilayer and 1.75±0.05 eV for trilayer molybdenum disulphide, which were directly grown on a graphite substrate by chemical vapour deposition method. More interestingly, we report an unexpected bandgap tunability (as large as 0.85±0.05 eV) with distance from the grain boundary in single-layer molybdenum disulphide, which also depends on the grain misorientation angle. This work opens up new possibilities for flexible electronic and optoelectronic devices with tunable bandgaps that utilize both the control of two-dimensional layer thickness and the grain boundary engineering.

  17. Structure and optical bandgap relationship of π-conjugated systems.

    Directory of Open Access Journals (Sweden)

    André Leitão Botelho

    Full Text Available In bulk heterojunction photovoltaic systems both the open-circuit voltage as well as the short-circuit current, and hence the power conversion efficiency, are dependent on the optical bandgap of the electron-donor material. While first-principles methods are computationally intensive, simpler model Hamiltonian approaches typically suffer from one or more flaws: inability to optimize the geometries for their own input; absence of general, transferable parameters; and poor performance for non-planar systems. We introduce a set of new and revised parameters for the adapted Su-Schrieffer-Heeger (aSSH Hamiltonian, which is capable of optimizing geometries, along with rules for applying them to any [Formula: see text]-conjugated system containing C, N, O, or S, including non-planar systems. The predicted optical bandgaps show excellent agreement to UV-vis spectroscopy data points from literature, with a coefficient of determination [Formula: see text], a mean error of -0.05 eV, and a mean absolute deviation of 0.16 eV. We use the model to gain insights from PEDOT, fused thiophene polymers, poly-isothianaphthene, copolymers, and pentacene as sources of design rules in the search for low bandgap materials. Using the model as an in-silico design tool, a copolymer of benzodithiophenes along with a small-molecule derivative of pentacene are proposed as optimal donor materials for organic photovoltaics.

  18. Photonic Hypercrystals

    Directory of Open Access Journals (Sweden)

    Evgenii E. Narimanov

    2014-10-01

    Full Text Available We introduce a new “universality class” of artificial optical media—photonic hypercrystals. These hyperbolic metamaterials, with periodic spatial variation of dielectric permittivity on subwavelength scale, combine the features of optical metamaterials and photonic crystals. In particular, surface waves supported by a hypercrystal possess the properties of both the optical Tamm states in photonic crystals and surface-plasmon polaritons at the metal-dielectric interface.

  19. Flexible all-solid-state asymmetric supercapacitors based on free-standing carbon nanotube/graphene and Mn3O4 nanoparticle/graphene paper electrodes.

    Science.gov (United States)

    Gao, Hongcai; Xiao, Fei; Ching, Chi Bun; Duan, Hongwei

    2012-12-01

    We report the design of all-solid-state asymmetric supercapacitors based on free-standing carbon nanotube/graphene (CNTG) and Mn(3)O(4) nanoparticles/graphene (MG) paper electrodes with a polymer gel electrolyte of potassium polyacrylate/KCl. The composite paper electrodes with carbon nanotubes or Mn(3)O(4) nanoparticles uniformly intercalated between the graphene nanosheets exhibited excellent mechanical stability, greatly improved active surface areas, and enhanced ion transportation, in comparison with the pristine graphene paper. The combination of the two paper electrodes with the polymer gel electrolyte endowed our asymmetric supercapacitor of CNTG//MG an increased cell voltage of 1.8 V, a stable cycling performance (capacitance retention of 86.0% after 10,000 continuous charge/discharge cycles), more than 2-fold increase of energy density (32.7 Wh/kg) compared with the symmetric supercapacitors, and importantly a distinguished mechanical flexibility.

  20. An all-solid state laser system for the laser ion source RILIS and in-source laser spectroscopy of astatine at ISOLDE, CERN

    CERN Document Server

    Rothe, Sebastian; Nörtershäuser, W

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at ISOLDE, CERN, by the addition of an all-solid state tuneable titanium: sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE, CERN, and at ISAC, TRIUMF, radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  1. An all-solid state laser system for the laser ion sources RILIS and in-source laser spectroscopy of astatine at ISOLDE/CERN

    International Nuclear Information System (INIS)

    Rothe, Sebastian

    2012-01-01

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  2. An all-solid state laser system for the laser ion sources RILIS and in-source laser spectroscopy of astatine at ISOLDE/CERN

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Sebastian

    2012-09-24

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  3. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  4. Layer Structured Bismuth Selenides of Bi2Se3 and Bi3Se4 for High Energy and Flexible All-Solid-State Micro-Supercapacitors.

    Science.gov (United States)

    Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

    2017-12-20

    Bismuth selenides (Bi2Se3 and Bi3Se4), both of which have the layered rhombohedral crystal structure, and found to be useful as electrode materials for supercapacitor application in this work. Bi2Se3 nanoplates as electrode material exhibit much better performance than that of Bi3Se4 nanoparticles in liquid electrolyte system (6 M KOH), which delivers a higher specific capacitance (272.9 F/g) than that of Bi3Se4 (193.6 F/g) at 5 mV/s. This result would may be attributed to that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to its planar quintuple stacked layers (septuple layers for Bi3Se4). For the demand of electronic skin, we used a novel flexible annular interdigital structure electrode applying for all-solid-state micro-supercapacitors (AMSCs). Bi2Se3 AMSCs device delivers a much more excellent supercapacitor performance, exhibits a large stack capacitance 89.5 F/cm3 (Bi3Se4: 79.1 F/cm3) at 20 mV/s, a high energy density 17.9 mWh/cm3 and high power density 18.9 W/cm3. The bismuth selenides also exhibit good cycle stability, retention 95.5% (90.3%) after 1000 c for Bi2Se3 (Bi3Se4). Obviously, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital all-solid-sate supercapacitor. © 2017 IOP Publishing Ltd.

  5. 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.

  6. Ordered photonic microstructures

    Science.gov (United States)

    Chen, Kevin Ming

    2001-09-01

    polystyrene latex colloidal particles into 2D crystals is presented. The colloidal assemblies offer a relatively easy processing route for fabrication of photonic bandgap structures. Large (>1 mm diameter) single crystal grains of colloids were formed using controlled evaporation and fluid flow techniques. A novel solution enabling post-processing of the fragile ordered assemblies is presented in which polyelectrolyte multilayers serve as adsorption platforms that anchor the colloidal assemblies. Tailorability of the polyelectrolyte surface properties (charge density, morphology) enables tuning of the colloid adsorption behavior. The polyelectrolyte surface affects colloid adsorption by influencing its surface diffusion. Observations of colloid surface diffusion were made using optical microscopy. Use of polyelectrolytes patterned via microcontact printing enables fabrication of colloid assemblies containing predesigned point and line defects. The patterned polyelectrolyte adsorption template allows placement of colloids in specific geometric arrangement, making possible the realization of sensors or functional photonic bandgap devices such as waveguides or photon traps. Three mechanisms were used to control adsorption: (1)pH of the colloid suspension, which determines the ionization of the uppermost surface of the polyelectrolyte multilayer; (2)ionic strength of the suspension, which determines the extent of charge screening about the colloid and polyelectrolyte; and (3)concentration of added surfactant, which causes charge screening and introduces hydrophobic interactions between the surfactant and polyelectrolyte. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253- 1690.)

  7. Controlling spontaneous emission of light by photonic crystals

    DEFF Research Database (Denmark)

    Lodahl, Peter

    2005-01-01

    Photonic bandgap crystals were proposed almost two decades ago as a unique tool for controlling propagation and emission of light. Since then the research field of photonic crystals has exploded and many beautiful demonstrations of the use of photonic crystals and fibers for molding light...... propagation have appeared that hold great promises for integrated optics. These major achievements solidly demonstrate the ability to control propagation of light. In contrast, an experimental demonstration of the use of photonic crystals for timing the emission of light has so far lacked. In a recent...... publication in Nature, we have demonstrated experimentally that both the direction and time of spontaneous emission can be controlled, thereby confirming the original proposal by Eli Yablonovich that founded the field of photonic crystals. We believe that this work opens new opportunities for solid...

  8. Tamm-plasmon and surface-plasmon hybrid-mode based refractometry in photonic bandgap structures.

    Science.gov (United States)

    Das, Ritwick; Srivastava, Triranjita; Jha, Rajan

    2014-02-15

    The transverse magnetic (TM) polarized hybrid modes formed as a consequence of coupling between Tamm plasmon polariton (TM-TPP) mode and surface plasmon polariton (SPP) mode exhibit interesting dispersive features for realizing a highly sensitive and accurate surface plasmon resonance (SPR) sensor. We found that the TM-TPP modes, formed at the interface of distributed Bragg reflector and metal, are strongly dispersive as compared to SPP modes at optical frequencies. This causes an appreciably narrow interaction bandwidth between TM-TPP and SPP modes, which leads to highly accurate sensing. In addition, appropriate tailoring of dispersion characteristics of TM-TPP as well as SPP modes could ensure high sensitivity of a novel SPR platform. By suitably designing the Au/TiO₂/SiO₂-based geometry, we propose a TM-TPP/SPP hybrid-mode sensor and achieve a sensitivity ≥900  nm/RIU with high detection accuracy (≥30  μm⁻¹) for analyte refractive indices varying between 1.330 and 1.345 in 600-700 nm wavelength range. The possibility to achieve desired dispersive behavior in any spectral band makes the sensing configuration an extremely attractive candidate to design sensors depending on the availability of optical sources.

  9. Tunable and rotatable birefringence controller based on electrical control of liquid crystal filled photonic bandgap fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

    2009-01-01

    We demonstrate the first compact electrically tunable and rotatable birefringence controller based on LCPBG fibers. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm.......We demonstrate the first compact electrically tunable and rotatable birefringence controller based on LCPBG fibers. The birefringence can be tuned electrically to work as a quarter-wave or a half-wave plate in the wavelength range 1520nm-1600nm....

  10. Photonic Crystal Fibres as the Transmission Medium for Future Optical Communication Systems

    DEFF Research Database (Denmark)

    Zsigri, Beata

    2006-01-01

    major groups: index guiding PCFs and photonic bandgap fibres (PBGFs). Several aspects of index guiding PCFs are similar to conventional fibres. On the contrary, PBGFs form a fundamentally new class of fibres and their properties differ considerably from those observed for both conventional fibres...

  11. Extreme group index measured and calculated in 2D SOI-based photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Jacobsen, Rune Shim; Fage-Pedersen, Jacob

    2005-01-01

    lattice of air-holes in the 216-nm thick silicon layer in an SOI material. Experimental transmission spectra show a mode cut-off around 1562.5 nm for the fundamental photonic bandgap mode. In order to measure and model the group index of modes in the PCW, a time-of-flight (ToF) method is applied....

  12. Colloidal Engineering for Infrared-Bandgap Solution-Processed Quantum Dot Solar Cells

    Science.gov (United States)

    Kiani, Amirreza

    harvesting for the first time. Addition of short bromothiol ligands during the synthesis significantly reduces the agglomeration of 1 eV bandgap CQDs and maintains efficient charge extraction into the selective electrodes. The devices can augment the performance of the best silicon cells by 7 power points where 0.8 additive power points are demonstrated experimentally. A tailored solution exchanged process developed for 1 eV bandgap CQDs results in air-stable IR PV devices with improved manufacturability. The process utilizes a tailored combination of lead iodide (PbI2) and ammonium acetate for the solution exchange and hexylamine + MEK as the final solvent to yield solar thick films with the filtered (1100 nm and beyond) performance of 0.4%. This thesis pushes the limit of CQD device applications to waste heat recovery. I demonstrate successful harvesting of low energy photons emitted from a hot object by designing and developing the first solution-processed thermophotovoltaic devices. These devices are comprised of 0.7 eV bandgap CQDs that successfully harvest photons emitted from an 800°C heat source.

  13. Wide bandgap engineering of (AlGa)2O3 films

    International Nuclear Information System (INIS)

    Zhang, Fabi; Saito, Katsuhiko; Tanaka, Tooru; Nishio, Mitsuhiro; Guo, Qixin; Arita, Makoto

    2014-01-01

    Bandgap tunable (AlGa) 2 O 3 films were deposited on sapphire substrates by pulsed laser deposition (PLD). The deposited films are of high transmittance as measured by spectrophotometer. The Al content in films is almost the same as that in targets. The measurement of bandgap energies by examining the onset of inelastic energy loss in core-level atomic spectra using X-ray photoelectron spectroscopy is proved to be valid for determining the bandgap of (AlGa) 2 O 3 films as it is in good agreement with the bandgap values from transmittance spectra. The measured bandgap of (AlGa) 2 O 3 films increases continuously with the Al content covering the whole Al content range from about 5 to 7 eV, indicating PLD is a promising growth technology for growing bandgap tunable (AlGa) 2 O 3 films.

  14. Strain-Modulated Bandgap and Piezo-Resistive Effect in Black Phosphorus Field-Effect Transistors.

    Science.gov (United States)

    Zhang, Zuocheng; Li, Likai; Horng, Jason; Wang, Nai Zhou; Yang, Fangyuan; Yu, Yijun; Zhang, Yu; Chen, Guorui; Watanabe, Kenji; Taniguchi, Takashi; Chen, Xian Hui; Wang, Feng; Zhang, Yuanbo

    2017-10-11

    Energy bandgap largely determines the optical and electronic properties of a semiconductor. Variable bandgap therefore makes versatile functionality possible in a single material. In layered material black phosphorus, the bandgap can be modulated by the number of layers; as a result, few-layer black phosphorus has discrete bandgap values that are relevant for optoelectronic applications in the spectral range from red, in monolayer, to mid-infrared in the bulk limit. Here, we further demonstrate continuous bandgap modulation by mechanical strain applied through flexible substrates. The strain-modulated bandgap significantly alters the density of thermally activated carriers; we for the first time observe a large piezo-resistive effect in black phosphorus field-effect transistors (FETs) at room temperature. The effect opens up opportunities for future development of electromechanical transducers based on black phosphorus, and we demonstrate an ultrasensitive strain gauge constructed from black phosphorus thin crystals.

  15. Liquid-infiltrated photonic crystals for lab-on-a-chip applications

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Pedersen, Jesper; Mortensen, Niels Asger

    2007-01-01

    In this paper we theoretically discuss how a strongly dispersive photonic crystals environment may be used to enhance the light-matter interactions, thus potentially compensating for the reduced optical path in typical lab-on- a-chip systems. Combining electromagnetic perturbation theory with ful......-wave electromagnetic simulations we address the prospects for slow-light enhancement of Beer-Lambert absorption and photonic band-gap based refractometry....

  16. Structural Color Palettes of Core-Shell Photonic Ink Capsules Containing Cholesteric Liquid Crystals.

    Science.gov (United States)

    Lee, Sang Seok; Seo, Hyeon Jin; Kim, Yun Ho; Kim, Shin-Hyun

    2017-06-01

    Photonic microcapsules with onion-like topology are microfluidically designed to have cholesteric liquid crystals with opposite handedness in their core and shell. The microcapsules exhibit structural colors caused by dual photonic bandgaps, resulting in a rich variety of color on the optical palette. Moreover, the microcapsules can switch the colors from either core or shell depending on the selection of light-handedness. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Robust microfluidic encapsulation of cholesteric liquid crystals toward photonic ink capsules.

    Science.gov (United States)

    Lee, Sang Seok; Kim, Bomi; Kim, Su Kyung; Won, Jong Chan; Kim, Yun Ho; Kim, Shin-Hyun

    2015-01-27

    Robust photonic microcapsules are created by microfluidic encapsulation of cholesteric liquid crystals with a hydrogel membrane. The membrane encloses the cholesteric core without leakage in water and the core exhibits pronounced structural colors. The photonic ink capsules, which have a precisely controlled bandgap position and size, provide new opportunities in colorimetric micro-thermometers and optoelectric applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Development of Sulfide Solid Electrolytes and Interface Formation Processes for Bulk-Type All-Solid-State Li and Na Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Akitoshi, E-mail: hayashi@chem.osakafu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan); Sakuda, Atsushi [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan); Department of Energy and Environment, Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka (Japan); Tatsumisago, Masahiro [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka (Japan)

    2016-07-15

    All-solid-state batteries with inorganic solid electrolytes (SEs) are recognized as an ultimate goal of rechargeable batteries because of their high safety, versatile geometry, and good cycle life. Compared with thin-film batteries, increasing the reversible capacity of bulk-type all-solid-state batteries using electrode active material particles is difficult because contact areas at solid–solid interfaces between the electrode and electrolyte particles are limited. Sulfide SEs have several advantages of high conductivity, wide electrochemical window, and appropriate mechanical properties, such as formability, processability, and elastic modulus. Sulfide electrolyte with Li{sub 7}P{sub 3}S{sub 11} crystal has a high Li{sup +} ion conductivity of 1.7 × 10{sup −2} S cm{sup −1} at 25°C. It is far beyond the Li{sup +} ion conductivity of conventional organic liquid electrolytes. The Na{sup +} ion conductivity of 7.4 × 10{sup −4} S cm{sup −1} is achieved for Na{sub 3.06}P{sub 0.94}Si{sub 0.06}S{sub 4} with cubic structure. Moreover, formation of favorable solid–solid interfaces between electrode and electrolyte is important for realizing solid-state batteries. Sulfide electrolytes have better formability than oxide electrolytes. Consequently, a dense electrolyte separator and closely attached interfaces with active material particles are achieved via “room-temperature sintering” of sulfides merely by cold pressing without heat treatment. Elastic moduli for sulfide electrolytes are smaller than that of oxide electrolytes, and Na{sub 2}S–P{sub 2}S{sub 5} glass electrolytes have smaller Young’s modulus than Li{sub 2}S–P{sub 2}S{sub 5} electrolytes. Cross-sectional SEM observations for a positive electrode layer reveal that sulfide electrolyte coating on active material particles increases interface areas even with a minimum volume of electrolyte, indicating that the energy density of bulk-type solid-state batteries is enhanced. Both surface coating

  19. Development of Lithium Stuffed Garnet-Type Oxide Solid Electrolytes with High Ionic Conductivity for Application to All-Solid-State Batteries

    Directory of Open Access Journals (Sweden)

    Ryoji Inada

    2016-07-01

    Full Text Available All-solid-state lithium-ion battery (LiB is expected as one of the next generation energy storage devices because of their high energy density, high safety and excellent cycle stability. Although oxide-based solid electrolyte materials have rather lower conductivity and poor deformability than sulfide-based one, they have other advantages such as their chemical stability and easiness for handling. Among the various oxide-based SEs, lithium stuffed garnet-type oxide with the formula of Li7La3Zr2O12 (LLZ have been widely studied because of their high conductivity above 10-4 Scm-1 at room temperature, excellent thermal performance and stability against Li metal anode.Here, we present our recent progress for the development of garnet-type solid electrolytes with high conductivity by simultaneous substitution of Ta5+ into Zr4+ site and Ba2+ into La3+ site in LLZ. Li+ concentration was fixed to 6.5 per chemical formulae, so that the formulae of our Li garnet-type oxide is expressed as Li6.5La3-xBaxZr1.5-xTa0.5+xO12 (LLBZT and Ba contents x are changed from 0 to 0.3. As results, all LLBZT samples have cubic garnet structure without containing any secondary phases. The lattice parameters of LLBZT decrease with increasing Ba2+ contents x < 0.10 while increase with x from 0.10 to 0.30, possibly due to the simultaneous change of Ba2+ and Ta5+ substitution levels. Relative densities of LLBZT are in the range between 89% and 93% and not influenced so much by the compositions. From AC impedance spectroscopy measurements, the total (bulk + grain conductivity at 27ºC of LLBZT shows its maximum value of 8.34 x 10-4 S cm-1 at x = 0.10, which is slightly higher than the conductivity (= 7.94 x 10-4 S cm-1 of LLZT without substituting Ba (x = 0. Activation energy of the conductivity tends to become lower by Ba substation, while excess Ba substitution degrades the conductivity in LLBZT. LLBZT has wide electrochemical potential window of 0-6 V vs. Li+/Li and

  20. Polyoxometalates@Metal-Organic Frameworks Derived Porous MoO3@CuO as Electrodes for Symmetric All-Solid-State Supercapacitor

    International Nuclear Information System (INIS)

    Zhang, Yidong; Lin, Baoping; Wang, Junchuan; Han, Pei; Xu, Tong; Sun, Ying; Zhang, Xueqin; Yang, Hong

    2016-01-01

    Highlights: • Porous MoO 3 @CuO was obtained from POMs@MOFs template. • A good charge capacity of 86.3 mAh g −1 was achieved in 1 M LiOH electrolyte. • The MoO 3 @CuO electrode was assembled into an all-solid-state device. • The introduction of MoO 3 improves the charge capacity. • The MoO 3 @CuO composite has good uniformity and porosity. - Abstract: The demand of uniformity and porosity for composite supercapacitor material has triggered tremendous research efforts for the development of doping method. Herein, we report an effective strategy for homogeneous and polyporous MoO 3 @CuO composite by heating a POMs@MOFs template (POMs = polyoxometalates, MOFs = Metal-organic frameworks), in which the Mo-POMs are incorporated into Cu-MOFs as secondary building units. The excellent doping of MoO 3 to CuO leads to an obvious improvement in specific discharge capacity (from 15.4 mAh g −1 for CuO to 86.3 mAh g −1 for MoO 3 @CuO). The layered structure of MoO 3 plays a key role in providing facilitated ion transport and electron diffusion pathways for the composite material. This electrode demonstrates excellent electrochemical performance with a specific discharge capacity of 86.3 mAh g −1 at 1 A g −1 in 1 M LiOH. When this porous MoO 3 @CuO electrode is assembled into a symmetric all-solid-state device with PVA-LiOH gel polymer, the as-fabricated device demonstrates good performance with an energy density of 7.9 W h kg −1 , power density of 8726 W kg −1 , and excellent cycle life. This work presents a new template to improve the uniformity and porosity of composite metal oxides, which can be used for high-performance supercapacitors.

  1. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters

    Science.gov (United States)

    Wanlass, Mark W [Golden, CO

    2011-11-29

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  2. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  3. Inverse photon-photon processes

    International Nuclear Information System (INIS)

    Carimalo, C.; Crozon, M.; Kesler, P.; Parisi, J.

    1981-12-01

    We here consider inverse photon-photon processes, i.e. AB → γγX (where A, B are hadrons, in particular protons or antiprotons), at high energies. As regards the production of a γγ continuum, we show that, under specific conditions the study of such processes might provide some information on the subprocess gg γγ, involving a quark box. It is also suggested to use those processes in order to systematically look for heavy C = + structures (quarkonium states, gluonia, etc.) showing up in the γγ channel. Inverse photon-photon processes might thus become a new and fertile area of investigation in high-energy physics, provided the difficult problem of discriminating between direct photons and indirect ones can be handled in a satisfactory way

  4. Switchable Photonic Crystals Using One-Dimensional Confined Liquid Crystals for Photonic Device Application.

    Science.gov (United States)

    Ryu, Seong Ho; Gim, Min-Jun; Lee, Wonsuk; Choi, Suk-Won; Yoon, Dong Ki

    2017-01-25

    Photonic crystals (PCs) have recently attracted considerable attention, with much effort devoted to photonic bandgap (PBG) control for varying the reflected color. Here, fabrication of a modulated one-dimensional (1D) anodic aluminum oxide (AAO) PC with a periodic porous structure is reported. The PBG of the fabricated PC can be reversibly changed by switching the ultraviolet (UV) light on/off. The AAO nanopores contain a mixture of photoresponsive liquid crystals (LCs) with irradiation-activated cis/trans photoisomerizable azobenzene. The resultant mixture of LCs in the porous AAO film exhibits a reversible PBG, depending on the cis/trans configuration of azobenzene molecules. The PBG switching is reliable over many cycles, suggesting that the fabricated device can be used in optical and photonic applications such as light modulators, smart windows, and sensors.

  5. Overcoming the Cut-Off Charge Transfer Bandgaps at the PbS Quantum Dot Interface

    KAUST Repository

    El-Ballouli, Ala'a O.

    2015-11-17

    Light harvesting from large size of semiconductor PbS quantum dots (QDs) with a bandgap of less than 1 eV is one of the greatest challenges precluding the development of PbS QD-based solar cells because the interfacial charge transfer (CT) from such QDs to the most commonly used electron acceptor materials is very inefficient, if it occurs at all. Thus, an alternative electron-accepting unit with a new driving force for CT is urgently needed to harvest the light from large-sized PbS QDs. Here, a cationic porphyrin is utilized as a new electron acceptor unit with unique features that bring the donor–acceptor components into close molecular proximity, allowing ultrafast and efficient electron transfer for QDs of all sizes, as inferred from the drastic photoluminescence quenching and the ultrafast formation of the porphyrin anionic species. The time-resolved results clearly demonstrate the possibility of modulating the electron transfer process between PbS QDs and porphyrin moieties not only by the size quantization effect but also by the interfacial electrostatic interaction between the positively charged porphyrin and the negatively charged QDs. This approach provides a new pathway for engineering QD-based solar cells that make the best use of the diverse photons making up the Sun\\'s broad irradiance spectrum.

  6. Overcoming the Cut-Off Charge Transfer Bandgaps at the PbS Quantum Dot Interface

    KAUST Repository

    El-Ballouli, Ala'a O.; Alarousu, Erkki; Kirmani, Ahmad R.; Amassian, Aram; Bakr, Osman; Mohammed, Omar F.

    2015-01-01

    Light harvesting from large size of semiconductor PbS quantum dots (QDs) with a bandgap of less than 1 eV is one of the greatest challenges precluding the development of PbS QD-based solar cells because the interfacial charge transfer (CT) from such QDs to the most commonly used electron acceptor materials is very inefficient, if it occurs at all. Thus, an alternative electron-accepting unit with a new driving force for CT is urgently needed to harvest the light from large-sized PbS QDs. Here, a cationic porphyrin is utilized as a new electron acceptor unit with unique features that bring the donor–acceptor components into close molecular proximity, allowing ultrafast and efficient electron transfer for QDs of all sizes, as inferred from the drastic photoluminescence quenching and the ultrafast formation of the porphyrin anionic species. The time-resolved results clearly demonstrate the possibility of modulating the electron transfer process between PbS QDs and porphyrin moieties not only by the size quantization effect but also by the interfacial electrostatic interaction between the positively charged porphyrin and the negatively charged QDs. This approach provides a new pathway for engineering QD-based solar cells that make the best use of the diverse photons making up the Sun's broad irradiance spectrum.

  7. A superhard sp3 microporous carbon with direct bandgap

    Science.gov (United States)

    Pan, Yilong; Xie, Chenlong; Xiong, Mei; Ma, Mengdong; Liu, Lingyu; Li, Zihe; Zhang, Shuangshuang; Gao, Guoying; Zhao, Zhisheng; Tian, Yongjun; Xu, Bo; He, Julong

    2017-12-01

    Carbon allotropes with distinct sp, sp2, and sp3 hybridization possess various different properties. Here, a novel all-sp3 hybridized tetragonal carbon, namely the P carbon, was predicted by the evolutionary particle swarm structural search. It demonstrated a low density among all-sp3 carbons, due to the corresponding distinctive microporous structure. P carbon is thermodynamically stable than the known C60 and could be formed through the single-walled carbon nanotubes (SWCNTs) compression. P carbon is a direct bandgap semiconductor displaying a strong and superhard nature. The unique combination of electrical and mechanical properties constitutes P carbon a potential superhard material for semiconductor industrial fields.

  8. Regioregular narrow-bandgap-conjugated polymers for plastic electronics

    Science.gov (United States)

    Ying, Lei; Huang, Fei; Bazan, Guillermo C.

    2017-03-01

    Progress in the molecular design and processing protocols of semiconducting polymers has opened significant opportunities for the fabrication of low-cost plastic electronic devices. Recent studies indicate that field-effect transistors and organic solar cells fabricated using narrow-bandgap regioregular polymers with translational symmetries in the direction of the backbone vector often outperform those containing analogous regiorandom polymers. This review addresses the cutting edge of regioregularity chemistry, in particular how to control the spatial distribution in the molecular structures and how this order translates to more ordered bulk morphologies. The effect of regioregularity on charge transport and photovoltaic properties is also outlined.

  9. High bandgap III-V alloys for high efficiency optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Alberi, Kirstin; Mascarenhas, Angelo; Wanlass, Mark

    2017-01-10

    High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al.sub.1-xIn.sub.xP layer, and a step-grade buffer between the substrate and at least one Al.sub.1-xIn.sub.xP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al.sub.1-xIn.sub.xP is reached.

  10. An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

    Directory of Open Access Journals (Sweden)

    Junko Kojima

    2015-06-01

    Full Text Available We developed a minimally invasive glucose monitoring system that uses a microneedle to permeate the skin surface and a small hydrogel to accumulate interstitial fluid glucose. The measurement of glucose and sodium ion levels in the hydrogel is required for estimating glucose levels in blood; therefore, we developed a small, enzyme-fixed glucose sensor with a high-selectivity, all-solid-state, sodium ion-selective electrode (ISE integrated into its design. The glucose sensor immobilized glucose oxidase showed a good correlation between the glucose levels in the hydrogels and the reference glucose levels (r > 0.99, and exhibited a good precision (coefficient of variation = 2.9%, 0.6 mg/dL. In the design of the sodium ISEs, we used the insertion material Na0.33MnO2 as the inner contact layer and DD16C5 exhibiting high Na+/K+ selectivity as the ionophore. The developed sodium ISE exhibited high selectivity (\\( \\log \\,k^{pot}_{Na,K} = -2.8\\ and good potential stability. The sodium ISE could measure 0.4 mM (10−3.4 M sodium ion levels in the hydrogels containing 268 mM (10−0.57 M KCl. The small integrated sensor (ϕ < 10 mm detected glucose and sodium ions in hydrogels simultaneously within 1 min, and it exhibited sufficient performance for use as a minimally invasive glucose monitoring system.

  11. A P2-Type Layered Superionic Conductor Ga-Doped Na2 Zn2 TeO6 for All-Solid-State Sodium-Ion Batteries.

    Science.gov (United States)

    Li, Yuyu; Deng, Zhi; Peng, Jian; Chen, Enyi; Yu, Yao; Li, Xiang; Luo, Jiahuan; Huang, Yangyang; Zhu, Jinlong; Fang, Chun; Li, Qing; Han, Jiantao; Huang, Yunhui

    2018-01-24

    Here, a P2-type layered Na 2 Zn 2 TeO 6 (NZTO) is reported with a high Na + ion conductivity ≈0.6×10 -3  S cm -1 at room temperature (RT), which is comparable to the currently best Na 1+n Zr 2 Si n P 3-n O 12 NASICON structure. As small amounts of Ga 3+ substitutes for Zn 2+ , more Na + vacancies are introduced in the interlayer gaps, which greatly reduces strong Na + -Na + coulomb interactions. Ga-substituted NZTO exhibits a superionic conductivity of ≈1.1×10 -3  S cm -1 at RT, and excellent phase and electrochemical stability. All solid-state batteries have been successfully assembled with a capacity of ≈70 mAh g -1 over 10 cycles with a rate of 0.2 C at 80 °C. 23 Na nuclear magnetic resonance (NMR) studies on powder samples show intra-grain (bulk) diffusion coefficients D NMR on the order of 12.35×10 -12  m 2  s -1 at 65 °C that corresponds to a conductivity σ NMR of 8.16×10 -3  S cm -1 , assuming the Nernst-Einstein equation, which thus suggests a new perspective of fast Na + ion conductor for advanced sodium ion batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. All-solid state symmetric supercapacitors based on compressible and flexible free-standing 3D carbon nanotubes (CNTs)/poly(3,4-ethylenedioxythiophene) (PEDOT) sponge electrodes

    Science.gov (United States)

    He, Xin; Yang, Wenyao; Mao, Xiling; Xu, Lu; Zhou, Yujiu; Chen, Yan; Zhao, Yuetao; Yang, Yajie; Xu, Jianhua

    2018-02-01

    Flexible supercapacitors that maintain electrochemical performance under deformation have attracted much attention for the potential application in the flexible electronics market. A compressible and flexible free-standing electrodes sponge and all-solid-state symmetric supercapacitors based on as-prepared electrodes are presented. The carbon nanotubes (CNTs) framework is synthesized by chemical vapor deposition (CVD) method, and then composited with poly (3,4-ethylenedioxythiophene) PEDOT by the electrodeposition. This CNTs/PEDOT sponge electrode shows highest mass-specific capacitance of 147 Fg-1 at 0.5 A g-1, tuned by the PEDOT mass loading, and exhibits good cyclic stability with the evidence that more than 95% of capacitance is remained after 3000 cycles. Furthermore, the symmetric supercapacitor shows the highest energy density of 12.6 Wh kg-1 under the power density of 1 kW kg-1 and highest power density of 10.2 kW kg-1 with energy density of 8 Wh kg-1, which exhibits both high energy density and power density. The electrochemical performance of composite electrode also indicates that the operate voltage of device could be extend to 1.4 V by the n-doping and p-doping process in different potential of PEDOT component. This flexible supercapacitor maintains stable electrochemical performance working on different bending condition, which shows promising prospect for wearable energy storage applications.

  13. Enhanced cycling stability of NiCo2S4@NiO core-shell nanowire arrays for all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Huang, Yuanyuan; Shi, Tielin; Jiang, Shulan; Cheng, Siyi; Tao, Xiangxu; Zhong, Yan; Liao, Guanglan; Tang, Zirong

    2016-12-01

    As a new class of pseudocapacitive material, metal sulfides possess high electrochemical performance. However, their cycling performance as conventional electrodes is rather poor for practical applications. In this article, we report an original composite electrode based on NiCo2S4@NiO core-shell nanowire arrays (NWAs) with enhanced cycling stability. This three-dimensional electrode also has a high specific capacitance of 12.2 F cm-2 at the current density of 1 mA cm-2 and excellent cycling stability (about 89% retention after 10,000 cycles). Moreover, an all-solid-state asymmetric supercapacitor (ASC) device has been assembled with NiCo2S4@NiO NWAs as the positive electrode and active carbon (AC) as the negative electrode, delivering a high energy density of 30.38 W h kg-1 at 0.288 KW kg-1 and good cycling stability (about 109% retention after 5000 cycles). The results show that NiCo2S4@NiO NWAs are promising for high-performance supercapacitors with stable cycling based on the unique core-shell structure and well-designed combinations.

  14. Controllable Synthesis of Atomically Thin Type-II Weyl Semimetal WTe2 Nanosheets: An Advanced Electrode Material for All-Solid-State Flexible Supercapacitors.

    Science.gov (United States)

    Yu, Peng; Fu, Wei; Zeng, Qingsheng; Lin, Junhao; Yan, Cheng; Lai, Zhuangchai; Tang, Bijun; Suenaga, Kazu; Zhang, Hua; Liu, Zheng

    2017-09-01

    Compared with 2D S-based and Se-based transition metal dichalcogenides (TMDs), Te-based TMDs display much better electrical conductivities, which will be beneficial to enhance the capacitances in supercapacitors. However, to date, the reports about the applications of Te-based TMDs in supercapacitors are quite rare. Herein, the first supercapacitor example of the Te-based TMD is reported: the type-II Weyl semimetal 1Td WTe 2 . It is demonstrated that single crystals of 1Td WTe 2 can be exfoliated into the nanosheets with 2-7 layers by liquid-phase exfoliation, which are assembled into air-stable films and further all-solid-state flexible supercapacitors. The resulting supercapacitors deliver a mass capacitance of 221 F g -1 and a stack capacitance of 74 F cm -3 . Furthermore, they also show excellent volumetric energy and power densities of 0.01 Wh cm -3 and 83.6 W cm -3 , respectively, superior to the commercial 4V/500 µAh Li thin-film battery and the commercial 3V/300 µAh Al electrolytic capacitor, in association with outstanding mechanical flexibility and superior cycling stability (capacitance retention of ≈91% after 5500 cycles). These results indicate that the 1Td WTe 2 nanosheet is a promising flexible electrode material for high-performance energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Characteristics of rapid-thermal-annealed LiCoO2 cathode film for an all-solid-state thin film microbattery

    International Nuclear Information System (INIS)

    Kim, Han-Ki; Yoon, Young Soo

    2004-01-01

    We report on the fabrication of a LiCoO 2 film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The LiCoO 2 films were grown by rf magnetron sputtering using a synthesized LiCoO 2 target in a [O 2 /(Ar+O 2 )] ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited LiCoO 2 film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed LiCoO 2 film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm2 μm. These results show the possibility of the RTA LiCoO 2 film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively

  16. An all-solid-state screen-printed carbon paste reference electrode based on poly(3,4-ethylenedioxythiophene) as solid contact transducer

    International Nuclear Information System (INIS)

    Xu, Hui; Pan, Yiwen; Chen, Ying; Ye, Ying; Wang, You; Li, Guang

    2012-01-01

    The paper presents the design of an all-solid-state portable reference electrode based on a screen-printed carbon paste electrode suitable for rapid human serum testing. The electrode was covered by electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) as an internal solid contact layer and polyvinyl chloride (PVC) membrane containing lipophilic anion and cation additives. The electrochemical properties of PEDOT(PSS) and PEDOT(PSS)/PVC film on a carbon paste electrode were studied by electrochemical impedance spectroscopy and cyclic voltammetry methods. The reference electrode exhibited good potential stability (for H + , Na + , K + , Ca 2+ , Cl − and CO 2− 3 /HCO − 3 ), good reproducibility and long-term stability. The structure is applied as reference electrodes in human serum pH analysis with pH ion selective planar electrodes, forming a serum pH sensor. The response time of such a pH sensor was 15 s and the sensitivity was −52.2 ± 1.0 mV per decade. Other properties, such as repeatability, reproducibility and stability, were also evaluated. Clinical trials were carried out and compared with the results obtained from the routine hospital electrolyte analyzer, which demonstrated that their analytical performance was closely matched. (paper)

  17. Bending impact on the performance of a flexible Li4Ti5O12-based all-solid-state thin-film battery.

    Science.gov (United States)

    Sepúlveda, Alfonso; Speulmanns, Jan; Vereecken, Philippe M

    2018-01-01

    The growing demand of flexible electronic devices is increasing the requirements of their power sources. The effect of bending in thin-film batteries is still not well understood. Here, we successfully developed a high active area flexible all-solid-state battery as a model system that consists of thin-film layers of Li 4 Ti 5 O 12 , LiPON, and Lithium deposited on a novel flexible ceramic substrate. A systematic study on the bending state and performance of the battery is presented. The battery withstands bending radii of at least 14 mm achieving 70% of the theoretical capacity. Here, we reveal that convex bending has a positive effect on battery capacity showing an average increase of 5.5%, whereas concave bending decreases the capacity by 4% in contrast with recent studies. We show that the change in capacity upon bending may well be associated to the Li-ion diffusion kinetic change through the electrode when different external forces are applied. Finally, an encapsulation scheme is presented allowing sufficient bending of the device and operation for at least 500 cycles in air. The results are meant to improve the understanding of the phenomena present in thin-film batteries while undergoing bending rather than showing improvements in battery performance and lifetime.

  18. Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment

    Science.gov (United States)

    Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

    2018-07-01

    The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS2 film was deposited on TiO2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO2 nanorod arrays were treated with hydrogen plasma(H:TiO2) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

  19. Hydrothermally formed three-dimensional hexagon-like P doped Ni(OH)2 rod arrays for high performance all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Li, Kunzhen; Li, Shikuo; Huang, Fangzhi; Lu, Yan; Wang, Lei; Chen, Hong; Zhang, Hui

    2018-01-01

    Three dimensional hexagon-like phosphrous (P) doped Ni(OH)2 rod arrays grown on Ni foam (NF) are fabricated by a facile and green one-step hydrothermal process. Ni foam is only reacted in a certain concentration of P containing H2O2 aqueous solution. The possible growth mechanism of the P doped Ni(OH)2 rod arrays is discussed. As a battery-type electrode material in situ formed on Ni foam, the binder-free P doped Ni(OH)2 rod arrays electrode displays a ultrahigh specific areal capacitance of 2.11C cm-2 (3.51 F cm-2) at 2 mA cm-2, and excellent cycling stability (95.5% capacitance retention after 7500 cycles). The assembled all-solid-state asymmetric supercapacitor (AAS) based on such P doped Ni(OH)2 rod arrays as the positive electrode and activated carbon as the negative electrode achieves an energy density of 81.3 Wh kg-1 at the power density of 635 W kg-1. The AAS device also exhibits excellent practical performance, which can easily drive an electric fan (3 W rated power) when two AAS devices are assembled in series. Thus, our synthesized P doped Ni(OH)2 rod arrays has a lot of potential applications in future energy storage prospects.

  20. In-situ growth of high-performance all-solid-state electrode for flexible supercapacitors based on carbon woven fabric/ polyaniline/ graphene composite

    Science.gov (United States)

    Lin, Yingxi; Zhang, Haiyan; Deng, Wentao; Zhang, Danfeng; Li, Na; Wu, Qibai; He, Chunhua

    2018-04-01

    For the development of wearable electronic devices, it is crucial to develop energy storage components combining high-capacity and flexibility. Herein, an all-solid-state supercapacitor is prepared through an in-situ "growth and wrapping" method. The electrode contains polyaniline deposited on a carbon woven fabric and wrapped with a graphene-based envelop. The hybrid electrode exhibits excellent mechanical and electrochemical performance. The optimized few layer graphene wrapping layer provides for a conductive network, which effectively enhances the cycling stability as 88.9% of the starting capacitance is maintained after 5000 charge/discharge cycles. Furthermore, the assembled device delivers a high areal capacity (of 790 F cm-2) at the current density of 1 A cm-2, a high areal energy (28.21 uWh cm-2) at the power densities of 0.12 mW cm-2 and shows no significant decrease in the performance with a bending angle of 180°. This unique flexible supercapacitor thus exhibits great potential for wearable electronics.

  1. All-Solid-State High-Energy Asymmetric Supercapacitors Enabled by Three-Dimensional Mixed-Valent MnOx Nanospike and Graphene Electrodes.

    Science.gov (United States)

    Yang, Jie; Li, Guizhu; Pan, Zhenghui; Liu, Meinan; Hou, Yuan; Xu, Yijun; Deng, Hong; Sheng, Leimei; Zhao, Xinluo; Qiu, Yongcai; Zhang, Yuegang

    2015-10-14

    Three-dimensional (3D) nanostructures enable high-energy storage devices. Here we report a 3D manganese oxide nanospike (NSP) array electrode fabricated by anodization and subsequent electrodeposition. All-solid-state asymmetric supercapacitors were assembled with the 3D Al@Ni@MnOx NSP as the positive electrode, chemically converted graphene (CCG) as the negative electrode, and Na2SO4/poly(vinyl alcohol) (PVA) as the polymer gel electrolyte. Taking advantage of the different potential windows of Al@Ni@MnOx NSP and CCG electrodes, the asymmetric supercapacitor showed an ideal capacitive behavior with a cell voltage up to 1.8 V, capable of lighting up a red LED indicator (nominal voltage of 1.8 V). The device could deliver an energy density of 23.02 W h kg(-1) at a current density of 1 A g(-1). It could also preserve 96.3% of its initial capacitance at a current density of 2 A g(-1) after 10000 charging/discharging cycles. The remarkable performance is attributed to the unique 3D NSP array structure that could play an important role in increasing the effective electrode surface area, facilitating electrolyte permeation, and shortening the electron pathway in the active materials.

  2. 5V-class bulk-type all-solid-state rechargeable lithium batteries with electrode-solid electrolyte composite electrodes prepared by aerosol deposition

    Science.gov (United States)

    Iriyama, Yasutoshi; Wadaguchi, Masaki; Yoshida, Koki; Yamamoto, Yuta; Motoyama, Munekazu; Yamamoto, Takayuki

    2018-05-01

    Composite electrodes (∼9 μm in thickness) composed of 5V-class electrode of LiNi0.5Mn1.5O4 (LNM) and high Li+ conductive crystalline-glass solid electrolyte (LATP, Ohara Inc.) were prepared at room temperature by aerosol deposition (AD) on platinum sheets. The resultant LNM-LATP composite electrodes were combined with LiPON and Li, and 5V-class bulk-type all-solid-state rechargeable lithium batteries (SSBs) were prepared. The crystallnity of the LNM in the LNM-LATP composite electrode was improved by annealing. Both thermogravimetry-mass spectroscopy analysis and XRD analysis clarified that the side reactions between the LNM and the LATP occurred over 500 °C with oxygen release. From these results, annealing temperature of the LNM-LATP composite electrode system was optimized at 500 °C due to the improved crystallinity of the LNM with avoiding the side-reactions. The SSBs with the composite electrodes (9 μm in thickness, 40 vol% of the LNM) annealed at 500 °C delivered 100 mAh g-1 at 10 μA cm-2 at 100 °C. Degradation of the discharge capacity with the repetition of the charge-discharge reactions was observed, which will originate from large volume change of the LNM (∼6.5%) during the reactions.

  3. Facilitated Oxygen Chemisorption in Heteroatom-Doped Carbon for Improved Oxygen Reaction Activity in All-Solid-State Zinc-Air Batteries.

    Science.gov (United States)

    Liu, Sisi; Wang, Mengfan; Sun, Xinyi; Xu, Na; Liu, Jie; Wang, Yuzhou; Qian, Tao; Yan, Chenglin

    2018-01-01

    Driven by the intensified demand for energy storage systems with high-power density and safety, all-solid-state zinc-air batteries have drawn extensive attention. However, the electrocatalyst active sites and the underlying mechanisms occurring in zinc-air batteries remain confusing due to the lack of in situ analytical techniques. In this work, the in situ observations, including X-ray diffraction and Raman spectroscopy, of a heteroatom-doped carbon air cathode are reported, in which the chemisorption of oxygen molecules and oxygen-containing intermediates on the carbon material can be facilitated by the electron deficiency caused by heteroatom doping, thus improving the oxygen reaction activity for zinc-air batteries. As expected, solid-state zinc-air batteries equipped with such air cathodes exhibit superior reversibility and durability. This work thus provides a profound understanding of the reaction principles of heteroatom-doped carbon materials in zinc-air batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Comparative Study of PVC-Free All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for the Determination of Dapoxetine Hydrochloride in Pharmaceutical Formulation.

    Science.gov (United States)

    Aziz, Azza; Khamees, Nesrin; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad

    2016-11-01

    The potentiometric response characteristics and analytical applications of a poly(vinyl chloride) (PVC)-free all-solid-state ion-selective electrode for dapoxetine hydrochloride (DAP) are examined. The Nernstian response of the electrode was evaluated by comparison with PVC-based liquid membrane and carbon paste electrodes. The PVC-free electrode is prepared by direct incorporation of dapoxetine-tetraphenyl borate (DAP-TPB) as a sensing element into a commercial nail varnish containing cellulose acetate propionate. The composite was applied onto a 3 mm diameter graphite disk electrode. The electrode exhibited a Nernstian slope of 56.0 mV/decade in the concentration range of 1 × 10-4 to 1 × 10-2 mol/L with an LOD of 2 × 10-5 mol/L. The electrode is independent of pH in the range of 2 to 6 and showed good selectivity for DAP with respect to a large number of inorganic cations and amino acids. Comparable Nernstian slope, sensitivity, pH range, and selectivity pattern were obtained with a PVC membrane and a carbon paste incorporating DAP-TPB as a sensing element and dioctylphthalate as a solvent mediator. The electrodes were used for the determination of DAP in pure solution and in tablets without extraction with high accuracy and precision (RSD ≤ 2%). The nail varnish solid-state electrode is simple, economical, and rapid when compared with PVC membrane and carbon paste electrodes.

  5. All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for Determination of Donepezil Hydrochloride in Pharmaceutical Formulation.

    Science.gov (United States)

    Khamees, Nesreen; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad; Aziz, Azza

    2017-09-01

    All-solid-state, polyvinyl chloride (PVC) membrane, and carbon paste potentiometric ion-selective electrodes (ISEs) were proposed for the determination of donepezil hydrochloride (DON) in the drug substance and a pharmaceutical formulation. The potentiometric response toward DON was based on the existence of donepezil-tetraphenyl borate (DON-TPB) in a PVC membrane or a carbon paste in the presence of dioctylphthalate. In contrast, the solid-state electrode was prepared by direct incorporation of DON-TPB into a commercial nail varnish without external additives. The electrodes exhibited Nernstian slopes of 55.0, 57.0, and 53.0 mV/decade over the concentration ranges of 1 × 10-5 to 1 × 10-3, 1 × 10-4 to 10-2, and 1 × 10-4 to 5 × 10-3 for the solid-state, PVC membrane, and carbon paste electrodes, respectively. The response of the electrodes is independent of pH in the range of 2-≤8. The electrodes showed good selectivity for DON with respect to a number of inorganic cations and amino acids. The electrodes were used for the determination of DON in pure solution and in pharmaceutical tablets with high accuracy (±2%) and precision (RSD ≤2%). The solid-state electrode is simple, economical, and rapid when compared to the PVC membrane and carbon paste electrodes.

  6. Rational Synthesis of Branched CoMoO4@CoNiO2 Core/Shell Nanowire Arrays for All-Solid-State Supercapacitors with Improved Performance.

    Science.gov (United States)

    Ai, Yuanfei; Geng, Xuewen; Lou, Zheng; Wang, Zhiming M; Shen, Guozhen

    2015-11-04

    Effectively composite materials with optimized structures exhibited promising potential in continuing improving the electrochemical performances of supercapacitors in the past few years. Here, we proposed a rational design of branched CoMoO4@CoNiO2 core/shell nanowire arrays on Ni foam by two steps of hydrothermal processing. Owing to the high activity of the scaffold-like CoMoO4 nanowires and the well-defined CoNiO2 nanoneedles, the three-dimensional (3D) electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (5.31 F/cm(2) at 5 mA/cm(2)) and superior cycling stability(159% of the original specific capacitance, i.e., 95.7% of the maximum retained after 5000 cycles at 30 mA/cm(2)). The all-solid-state asymmetric supercapacitors composed of such electrode and activated carbon (AC) exhibited an areal specific capacitance of 1.54 F/cm(2) at 10 mA/cm(2) and a rate capability (59.75 Wh/kg at a 1464 W/kg) comparable with Li-ion batteries. It also showed an excellent cycling stability with no capacitance attenuation after 50000 cycles at 100 mA/cm(2). After rapid charging (1 s), such supercapacitors in series could lighten a red LED for a long time and drive a mini motor effectively, demonstrating advances in energy storage, scalable integrated applications, and promising commercial potential.

  7. Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment.

    Science.gov (United States)

    Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

    2018-07-06

    The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS 2 film was deposited on TiO 2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO 2 nanorod arrays were treated with hydrogen plasma(H:TiO 2 ) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

  8. In-situ Plasticized Cross-linked Polymer Composite Electrolyte Enhanced with Lithium-ion Conducting Nanofibers for Ambient All-Solid-State Lithium-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Chaoyi; Zhu, Pei; Jia, Hao; Zhu, Jiadeng; Selvan, R. Kalai; Li, Ya; Dong, Xia; Du, Zhuang; Angunawela, Indunil; Wu, Nianqiang; Dirican, Mahmut

    2018-04-29

    Solid electrolytes have been gaining attention recently for the development of next-generation Li-ion batteries due to the substantial improvements in stability and safety. Among various types of solid electrolytes, composite solid electrolytes (CSEs) exhibit both high ionic conductivity and excellent interfacial contact with the electrodes. Incorporating active nanofibers into the polymer matrix demonstrates an effective method to fabricate CSEs. However, current CSEs based on traditional poly(ethylene oxide) (PEO) polymer suffer from the poor ionic conductivity of PEO and agglomeration effect of inorganic fillers at high concentrations, which limit further improvements in Li+ conductivity and electrochemical stability. Herein, we synthesize a novel PEO based cross-linked polymer (CLP) as the polymer matrix with naturally amorphous structure and high room-temperature ionic conductivity of 2.40 × 10-4 S cm-1. Li0.3La0.557TiO3 (LLTO) nanofibers incorporated composite solid electrolytes (L-CLPCSE) exhibit enhanced ionic conductivity without showing filler agglomeration. The high content of Li-conductive nanofibers improves the mechanical strength, ensures the conductive networks, and increases the total Li+ conductivity to 3.31 × 10-4 S cm-1. The all-solid-state Li|LiFePO4 batteries with L-CLPCSE are able to deliver attractive specific capacity of 147 mAh g-1 at room temperature, and no evident dendrite is found at the anode/electrolyte interface after 100 cycles.

  9. Photon generator

    Science.gov (United States)

    Srinivasan-Rao, Triveni

    2002-01-01

    A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

  10. Wide-bandgap epitaxial heterojunction windows for silicon solar cells

    Science.gov (United States)

    Landis, Geoffrey A.; Loferski, Joseph J.; Beaulieu, Roland; Sekula-Moise, Patricia A.; Vernon, Stanley M.

    1990-01-01

    It is shown that the efficiency of a solar cell can be improved if minority carriers are confined by use of a wide-bandgap heterojunction window. For silicon (lattice constant a = 5.43 A), nearly lattice-matched wide-bandgap materials are ZnS (a = 5.41 A) and GaP (a = 5.45 A). Isotype n-n heterojuntions of both ZnS/Si and GaP/Si were grown on silicon n-p homojunction solar cells. Successful deposition processes used were metalorganic chemical vapor deposition (MO-CVD) for GaP and ZnS, and vacuum evaporation of ZnS. Planar (100) and (111) and texture-etched - (111)-faceted - surfaces were used. A decrease in minority-carrier surface recombination compared to a bare surface was seen from increased short-wavelength spectral response, increased open-circuit voltage, and reduced dark saturation current, with no degradation of the minority carrier diffusion length.

  11. Tunable Bandgap and Optical Properties of Black Phosphorene Nanotubes

    Directory of Open Access Journals (Sweden)

    Chunmei Li

    2018-02-01

    Full Text Available Black phosphorus (BP, a new two-dimensional material, has been the focus of scientists’ attention. BP nanotubes have potential in the field of optoelectronics due to their low-dimensional effects. In this work, the bending strain energy, electronic structure, and optical properties of BP nanotubes were investigated by using the first-principles method based on density functional theory. The results show that these properties are closely related to the rolling direction and radius of the BP nanotube. All the calculated BP nanotube properties show direct bandgaps, and the BP nanotubes with the same rolling direction express a monotone increasing trend in the value of bandgap with a decrease in radius, which is a stacking effect of the compression strain on the inner atoms and the tension strain on the outer atoms. The bending strain energy of the zigzag phosphorene nanotubes (zPNTs is higher than that of armchair phosphorene nanotubes (aPNT with the same radius of curvature due to the anisotropy of the BP’s structure. The imaginary part of the dielectric function, the absorption range, reflectivity, and the imaginary part of the refractive index of aPNTs have a wider range than those of zPNTs, with higher values overall. As a result, tunable BP nanotubes are suitable for optoelectronic devices, such as lasers and diodes, which function in the infrared and ultra-violet regions, and for solar cells and photocatalysis.

  12. Optical bandgap of semiconductor nanostructures: Methods for experimental data analysis

    Science.gov (United States)

    Raciti, R.; Bahariqushchi, R.; Summonte, C.; Aydinli, A.; Terrasi, A.; Mirabella, S.

    2017-06-01

    Determination of the optical bandgap (Eg) in semiconductor nanostructures is a key issue in understanding the extent of quantum confinement effects (QCE) on electronic properties and it usually involves some analytical approximation in experimental data reduction and modeling of the light absorption processes. Here, we compare some of the analytical procedures frequently used to evaluate the optical bandgap from reflectance (R) and transmittance (T) spectra. Ge quantum wells and quantum dots embedded in SiO2 were produced by plasma enhanced chemical vapor deposition, and light absorption was characterized by UV-Vis/NIR spectrophotometry. R&T elaboration to extract the absorption spectra was conducted by two approximated methods (single or double pass approximation, single pass analysis, and double pass analysis, respectively) followed by Eg evaluation through linear fit of Tauc or Cody plots. Direct fitting of R&T spectra through a Tauc-Lorentz oscillator model is used as comparison. Methods and data are discussed also in terms of the light absorption process in the presence of QCE. The reported data show that, despite the approximation, the DPA approach joined with Tauc plot gives reliable results, with clear advantages in terms of computational efforts and understanding of QCE.

  13. Wide bandgap collector III-V double heterojunction bipolar transistors

    International Nuclear Information System (INIS)

    Flitcroft, R.M.

    2000-10-01

    This thesis is devoted to the study and development of Heterojunction Bipolar Transistors (HBTs) designed for high voltage operation. The work concentrates on the use of wide bandgap III-V semiconductor materials as the collector material and their associated properties influencing breakdown, such as impact ionisation coefficients. The work deals with issues related to incorporating a wide bandgap collector into double heterojunction structures such as conduction band discontinuities at the base-collector junction and results are presented which detail, a number of methods designed to eliminate the effects of such discontinuities. In particular the use of AlGaAs as the base material has been successful in eliminating the conduction band spike at this interface. A method of electrically injecting electrons into the collector has been employed to investigate impact ionisation in GaAs, GaInP and AlInP which has used the intrinsic gain of the devices to extract impact ionisation coefficients over a range of electric fields beyond the scope of conventional optical injection techniques. This data has enabled the study of ''dead space'' effects in HBT collectors and have been used to develop an analytical model of impact ionisation which has been incorporated into an existing Ebers-Moll HBT simulator. This simulator has been shown to accurately reproduce current-voltage characteristics in both the devices used in this work and for external clients. (author)

  14. Development of Lithium-Stuffed Garnet-Type Oxide Solid Electrolytes with High Ionic Conductivity for Application to All-Solid-State Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Inada, Ryoji, E-mail: inada@ee.tut.ac.jp; Yasuda, Satoshi; Tojo, Masaru; Tsuritani, Keiji; Tojo, Tomohiro; Sakurai, Yoji [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Toyohashi (Japan)

    2016-07-20

    All-solid-state lithium-ion batteries are expected to be one of the next generations of energy storage devices because of their high energy density, high safety, and excellent cycle stability. Although oxide-based solid electrolyte (SE) materials have rather lower conductivity and poor deformability than sulfide-based ones, they have other advantages, such as their chemical stability and ease of handling. Among the various oxide-based SEs, lithium-stuffed garnet-type oxide, with the formula of Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZ), has been widely studied because of its high conductivity above 10{sup −4} S cm{sup −1} at room temperature, excellent thermal performance, and stability against Li metal anode. Here, we present our recent progress for the development of garnet-type SEs with high conductivity by simultaneous substitution of Ta{sup 5+} into the Zr{sup 4+} site and Ba{sup 2+} into the La{sup 3+} site in LLZ. Li{sup +} concentration was fixed to 6.5 per chemical formulae, so that the formula of our Li garnet-type oxide is expressed as Li{sub 6.5}La{sub 3−x}Ba{sub x}Zr{sub 1.5−x}Ta{sub 0.5+x}O{sub 12} (LLBZT) and Ba contents x are changed from 0 to 0.3. As a result, all LLBZT samples have a cubic garnet structure without containing any secondary phases. The lattice parameters of LLBZT decrease with increasing Ba{sup 2+} contents x ≤ 0.10 while increase with x from 0.10 to 0.30, possibly due to the simultaneous change of Ba{sup 2+} and Ta{sup 5+} substitution levels. The relative densities of LLBZT are in a range between 89 and 93% and are not influenced in any significant way by the compositions. From the AC impedance spectroscopy measurements, the total (bulk + grain) conductivity at 27°C of LLBZT shows its maximum value of 8.34 × 10{sup −4} S cm{sup −1} at x = 0.10, which is slightly higher than the conductivity (= 7.94 × 10{sup −4} S cm{sup −1}) of LLZT without substituting Ba (x = 0). The activation energy of the conductivity

  15. Limits of slow light in photonic crystals

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Xiao, Sanshui; Mortensen, N. Asger

    2008-01-01

    in the group velocity acquiring a finite value above zero at the band-gap edges while attaining uperluminal values within the band gap. Simple scalings of the minimum and maximum group velocities with the imaginary part of the dielectric function or, equivalently, the linewidth of the broadened states......While ideal photonic crystals would support modes with a vanishing group velocity, state-of-the-art structures have still only provided a slow down by roughly two orders of magnitude. We find that the induced density of states caused by lifetime broadening of the electromagnetic modes results...... are presented. The results obtained are entirely general and may be applied to any effect which results in a broadening of the electromagnetic states, such as loss, disorder, and finite-size effects. This significantly limits the reduction in group velocity attainable via photonic crystals....

  16. Manganese dioxide decoration of macroscopic carbon nanotube fibers: From high-performance liquid-based to all-solid-state supercapacitors

    Science.gov (United States)

    Pendashteh, Afshin; Senokos, Evgeny; Palma, Jesus; Anderson, Marc; Vilatela, Juan J.; Marcilla, Rebeca

    2017-12-01

    Supercapacitors capable of providing high voltage, energy and power density but yet light, low volume occupying, flexible and mechanically robust are highly interesting and demanded for portable applications. Herein, freestanding flexible hybrid electrodes based on MnO2 nanoparticles grown on macroscopic carbon nanotube fibers (CNTf-MnO2) were fabricated, without the need of any metallic current collector. The CNTf, a support with excellent electrical conductivity, mechanical stability, and appropriate pore structure, was homogeneously decorated with porous akhtenskite ɛ-MnO2 nanoparticles produced via electrodeposition in an optimized organic-aqueous mixture. Electrochemical properties of these decorated fibers were evaluated in different electrolytes including a neutral aqueous solution and a pure 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (PYR14TFSI). This comparison helps discriminate the various contributions to the total capacitance: (surface) Faradaic and non-Faradaic processes, improved wetting by aqueous electrolytes. Accordingly, symmetric supercapacitors with PYR14TFSI led to a high specific energy of 36 Wh· kgMnO2-1 (16 Wh·kg-1 including the weight of CNTf) and real specific power of 17 kW· kgMnO2-1 (7.5 kW kg-1) at 3.0 V with excellent cycling stability. Moreover, flexible all solid-state supercapacitors were fabricated using PYR14TFSI-based polymer electrolyte, exhibiting maximum energy density of 21 Wh·kg-1 and maximum power density of 8 kW kg-1 normalized by total active material.

  17. Layer structured bismuth selenides Bi2Se3 and Bi3Se4 for high energy and flexible all-solid-state micro-supercapacitors

    Science.gov (United States)

    Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

    2018-02-01

    In this work, bismuth selenides (Bi2Se3 and Bi3Se4), both of which have a layered rhombohedral crystal structure, have been found to be useful as electrode materials for supercapacitor applications. In a liquid electrolyte system (6M KOH), Bi2Se3 nanoplates exhibit much better performance as an electrode material than Bi3Se4 nanoparticles do, delivering a higher specific capacitance (272.9 F g-1) than that of Bi3Se4 (193.6 F g-1) at 5 mV s-1. This result may be attributed to the fact that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to their planar quintuple stacked layers (septuple layers for Bi3Se4). To meet the demands of electronic skin, we used a novel flexible annular interdigital structure electrode to support the all-solid-state micro-supercapacitors (AMSCs). The Bi2Se3 AMSC device delivers a much better supercapacitor performance, exhibits a large stack capacitance of 89.5 F cm-3 at 20 mV s-1 (Bi3Se4: 79.1 F cm-3), a high energy density of 17.9 mWh cm-3 and a high power density of 18.9 W cm-3. The bismuth selenides also exhibit good cycle stability, with 95.5% retention after 1000 c for Bi2Se3 (Bi3Se4:90.3%). Clearly, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital AMSCs.

  18. All-solid-state, synchronously pumped, ultrafast BaWO4 Raman laser with long and short Raman shifts generating at 1180, 1225, and 1323 nm

    Science.gov (United States)

    Frank, Milan; Jelínek, Michal; Kubeček, Václav; Ivleva, Lyudmila I.; Zverev, Petr G.; Smetanin, Sergei

    2017-12-01

    A lot of attention is currently focused on synchronously pumped, extra-cavity crystalline Raman lasers generating one or two Stokes Raman components in KGW or diamond Raman-active crystals, and also generating additional components of stimulated polariton scattering in lithium niobate crystal having both cubic and quadratic nonlinearities. In this contribution we report on generation of more than two Stokes components of stimulated Raman scattering with different Raman shifts in the all-solid-state, synchronously pumped, extra-cavity Raman laser based on the Raman-active a-cut BaWO4 crystal excited by a mode-locked, 220 nJ, 36 ps, 150 MHz diode sidepumped Nd:GdVO4 laser generating at the wavelength of 1063 nm. Excitation by the pumping radiation polarized along the BaWO4 crystal optical axis resulted in the Raman generation with not only usual (925cm - 1), but also additional (332cm - 1) Raman shift. Besides the 1180-nm first and 1323 nm second Stokes components with the Raman shift of 925cm - 1 from the 1063nm fundamental laser wavelength, we have achieved generation of the additional 1227 nm Raman component with different Raman shift of 332cm - 1 from the 1180nm component. At the 1227 nm component the strongest 12-times pulse shortening from 36ps down to 3ps was obtained due to shorter dephasing time of this additional Raman line (3ps for the 332-cm - 1 line instead of 6.5ps for the 925cm - 1 line). It has to be also noted that the 1225 nm generation is intracavity pumped by the 1179 nm first Stokes component resulting in the strongest pulse shortening close to the 332cm -1 line dephasing time (3ps). Slope efficiency of three Stokes components generation exceeded 20%.

  19. Two photon processes in surface photovoltage spectroscopy

    International Nuclear Information System (INIS)

    Craig, R.P.; Thurgate, S.M.

    1996-01-01

    Full text: A significant mid-gap effect has been found in Surface Photovoltage Spectroscopy measurements of cleaved GaAs, InP and Si wafer which is normally interpreted as arising from transitions between surface states and band edges. This large mid-gap effect common to various materials is puzzling as such a high proportion of mid-gap states seems unlikely. Most theories of surface states predict states that tail from the band edges into the gap or states that have a well defined energy in the gap. None propose a large state exactly at E G /2. We recently investigated the variation in SPS spectra with flux density. We find a non-linear correlation in the magnitude of Band-Bending arising from mid-gap and band-gap photon energies. We suggest that the mid-gap feature is due to a two photon absorption process leading to carrier pair generation mediated by mid-gap states in the continuum of band-gap surface states

  20. Quantum photonics

    CERN Document Server

    Pearsall, Thomas P

    2017-01-01

    This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of non­locality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...

  1. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

    2013-01-01

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump...... wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode...... area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions....

  2. Electrospun fibrous electrodes with tunable microstructure made of polyaniline/multi-walled carbon nanotube suspension for all-solid-state supercapacitors

    International Nuclear Information System (INIS)

    Liang, Junsheng; Su, Shijie; Fang, Xu; Wang, Dazhi; Xu, Shuangchao

    2016-01-01

    Highlights: • Electrospun PANI/MWCNT fibrous electrodes for supercapacitor were prepared. • Microstructure of electrodes is tunable by changing the electrospin parameters. • Fiber-diameter dependence of the electrode performance was observed. • High performance and good stability of electrospun electrodes were obtained. - Abstract: Electrospinning technique was used to prepare high performance fibrous electrodes with tunable microstructure for all-solid-state electrochemical supercapacitor. Symmetrically sandwiched supercapacitors consisting of flexible electrospun polyaniline (PANI)/multi-walled carbon nanotube (MWCNT) electrodes and polyvinyl alcohol (PVA)/sulfuric acid (H_2SO_4) gel electrolyte were assembled. Tunable microstructure of the fibrous electrode was obtained by changing the electrospinning parameters including the collector–needle distance (CND) and the suspension flow rate (SFR). Results show that, higher CND combining with lower SFR can result in a smaller average diameter of the electrospun fibers and hence improve the electrode performance. When the CND changes from 80 to 140 mm, the average fiber diameter will decrease from 2.89 to 1.21 μm, and the specific surface area of the electrode can increase from 57 to 83 m"2·g"−"1. The corresponding specific capacitance of the electrospun electrode will therefore increase from 129.5 to 180 F·g"−"1, leading to a synchronous improvement of the energy density of the supercapacitor from 18 to 25 Wh·kg"−"1. On the other hand, the supercapacitors using fibrous electrodes in this work also show good rate capability and cycling stability. Using the electrode with an average fiber diameter of 1.21 μm, the specific capacitances can maintain 131 F·g"−"1 at a current density of 4 A·g"−"1, which is 73% of the specific capacitance of the same sample at a current density of 0.5 A·g"−"1. And the specific capacitance of the electrode can retain 89% after 1500 charge/discharge cycles.

  3. Electrospun fibrous electrodes with tunable microstructure made of polyaniline/multi-walled carbon nanotube suspension for all-solid-state supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Junsheng; Su, Shijie; Fang, Xu [Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116023 (China); Wang, Dazhi, E-mail: d.wang@dlut.edu.cn [Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116023 (China); Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116023 (China); Xu, Shuangchao [Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116023 (China)

    2016-09-15

    Highlights: • Electrospun PANI/MWCNT fibrous electrodes for supercapacitor were prepared. • Microstructure of electrodes is tunable by changing the electrospin parameters. • Fiber-diameter dependence of the electrode performance was observed. • High performance and good stability of electrospun electrodes were obtained. - Abstract: Electrospinning technique was used to prepare high performance fibrous electrodes with tunable microstructure for all-solid-state electrochemical supercapacitor. Symmetrically sandwiched supercapacitors consisting of flexible electrospun polyaniline (PANI)/multi-walled carbon nanotube (MWCNT) electrodes and polyvinyl alcohol (PVA)/sulfuric acid (H{sub 2}SO{sub 4}) gel electrolyte were assembled. Tunable microstructure of the fibrous electrode was obtained by changing the electrospinning parameters including the collector–needle distance (CND) and the suspension flow rate (SFR). Results show that, higher CND combining with lower SFR can result in a smaller average diameter of the electrospun fibers and hence improve the electrode performance. When the CND changes from 80 to 140 mm, the average fiber diameter will decrease from 2.89 to 1.21 μm, and the specific surface area of the electrode can increase from 57 to 83 m{sup 2}·g{sup −1}. The corresponding specific capacitance of the electrospun electrode will therefore increase from 129.5 to 180 F·g{sup −1}, leading to a synchronous improvement of the energy density of the supercapacitor from 18 to 25 Wh·kg{sup −1}. On the other hand, the supercapacitors using fibrous electrodes in this work also show good rate capability and cycling stability. Using the electrode with an average fiber diameter of 1.21 μm, the specific capacitances can maintain 131 F·g{sup −1} at a current density of 4 A·g{sup −1}, which is 73% of the specific capacitance of the same sample at a current density of 0.5 A·g{sup −1}. And the specific capacitance of the electrode can retain 89

  4. Atmospheric measurements of OH, HO2 and NO by laser-induced fluorescence spectroscopy using a compact all solid-state laser system

    Science.gov (United States)

    Bloss, W. J.; Floquet, C.; Gravestock, T. J.; Heard, D. E.; Ingham, T.; Johnson, G. P.; Lee, J. D.

    2003-04-01

    Free-radicals are key intermediates that control the budgets of many trace gases, for example ozone, greenhouse gases and harmful pollutants. Measurement of radicals and comparison with model calculations constitutes an important test of our understanding of the underlying chemistry. There is a greater need for compact and lightweight instruments for the in situ measurement of free-radical species that are suitable for deployment from a number of field-platforms. A new field instrument has been developed that incorporates an all solid-state Nd:YAG pumped titanium sapphire laser that is capable of generating radiation at high pulse-repetition-frequency for the detection of OH, HO_2, NO and IO radicals in the atmosphere by laser induced fluorescence (LIF). The system offers advantages of wide wavelength tunability, compactness, low weight, greater long-term stability (fibre-optic delivery) and short warm-up time. The instrument was successfully deployed during 2002 in the NAMBLEX field campaign at Mace Head with detection limits for OH and HO_2 (measured simultaneously with laser operation at 308 nm) of 3.1 x 10^5 molecule cm-3 (0.012 ppt) and 2.6 x 10^6 molecule cm-3 (0.09 pptv) respectively. Diurnal profiles of OH have been recorded over a period of 5 weeks. NO controls the HO_2/OH ratio and is the critical parameter in the production of tropospheric ozone, yet measurements in the boundary layer are restricted to a single indirect technique based on chemiluminescent analysers. Measurements of NO in the atmosphere have been made by LIF using the new instrument operating at 226 nm, with absolute concentrations in good agreement with simultaneous measurements made using a commercial chemiluminescent analyser. Whilst operating at 445 nm, the instrument has detected the IO radical in the laboratory, with a projected detection limit that is well below previously measured atmospheric concentrations of IO. A second instrument to be deployed on an aircraft platform is

  5. Plasma Reflection in Multigrain Layers of Narrow-Bandgap Semiconductors

    Science.gov (United States)

    Zhukov, N. D.; Shishkin, M. I.; Rokakh, A. G.

    2018-04-01

    Qualitatively similar spectral characteristics of plasma-resonance reflection in the region of 15-25 μm were obtained for layers of electrodeposited submicron particles of InSb, InAs, and GaAs and plates of these semiconductors ground with M1-grade diamond powder. The most narrow-bandgap semiconductor InSb (intrinsic absorption edge ˜7 μm) is characterized by an absorption band at 2.1-2.3 μm, which is interpreted in terms of the model of optical excitation of electrons coupled by the Coulomb interaction. The spectra of a multigrain layer of chemically deposited PbS nanoparticles (50-70 nm) exhibited absorption maxima at 7, 10, and 17 μm, which can be explained by electron transitions obeying the energy-quantization rules for quantum dots.

  6. Copper-organic/octamolybdates: structures, bandgap sizes, and photocatalytic activities.

    Science.gov (United States)

    Luo, Lan; Lin, Haisheng; Li, Le; Smirnova, Tatyana I; Maggard, Paul A

    2014-04-07

    The structures, optical bandgap sizes, and photocatalytic activities are described for three copper-octamolybdate hybrid solids prepared using hydrothermal methods, [Cu(pda)]4[β-Mo8O26] (I; pda = pyridazine), [Cu(en)2]2[γ-Mo8O26] (II; en = ethylenediamine), and [Cu(o-phen)2]2[α-Mo8O26] (III; o-phen = o-phenanthroline). The structure of I consists of a [Cu(pda)]4(4+) tetramer that bridges to neighboring [β-Mo8O26](4-) octamolybdate clusters to form two-dimensional layers that stack along the a axis. The previously reported structures of II and III are constructed from [Cu2(en)4Mo8O26] and [Cu2(o-phen)4Mo8O26] clusters. The optical bandgap sizes were measured by UV-vis diffuse reflectance techniques to be ∼1.8 eV for I, ∼3.1 eV for II, and ∼3.0 eV for III. Electronic structure calculations show that the smaller bandgap size of I originates primarily from an electronic transition between the valence and conduction band edges comprised of filled 3d(10) orbitals on Cu(I) and empty 4d(0) orbitals on Mo(VI). Both II and III contain Cu(II) and exhibit larger bandgap sizes. Accordingly, aqueous suspensions of I exhibit visible-light photocatalytic activity for the production of oxygen at a rate of ∼90 μmol O2 g(-1) h(-1) (10 mg samples; radiant power density of ∼1 W/cm(2)) and a turnover frequency per calculated surface [Mo8O26](4-) cluster of ∼36 h(-1). Under combined ultraviolet and visible-light irradiation, I also exhibits photocatalytic activity for hydrogen production in 20% aqueous methanol of ∼316 μmol H2 g(-1) h(-1). By contrast, II decomposed during the photocatalysis measurements. The molecular [Cu2(o-phen)4(α-Mo8O26)] clusters of III dissolve into the aqueous methanol solution under ultraviolet irradiation and exhibit homogeneous photocatalytic rates for hydrogen production of up to ∼8670 μmol H2·g(-1) h(-1) and a turnover frequency of 17 h(-1). The clusters of III can be precipitated out by evaporation and redispersed into solution with

  7. Semiconductor Metal-Organic Frameworks: Future Low-Bandgap Materials.

    Science.gov (United States)

    Usman, Muhammad; Mendiratta, Shruti; Lu, Kuang-Lieh

    2017-02-01

    Metal-organic frameworks (MOFs) with low density, high porosity, and easy tunability of functionality and structural properties, represent potential candidates for use as semiconductor materials. The rapid development of the semiconductor industry and the continuous miniaturization of feature sizes of integrated circuits toward the nanometer (nm) scale require novel semiconductor materials instead of traditional materials like silicon, germanium, and gallium arsenide etc. MOFs with advantageous properties of both the inorganic and the organic components promise to serve as the next generation of semiconductor materials for the microelectronics industry with the potential to be extremely stable, cheap, and mechanically flexible. Here, a perspective of recent research is provided, regarding the semiconducting properties of MOFs, bandgap studies, and their potential in microelectronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Green photonics

    International Nuclear Information System (INIS)

    Quan, Frederic

    2012-01-01

    Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas. (review article)

  9. Energy transfer and visible-infrared quantum cutting photoluminescence modification in Tm-Yb codoped YPO(4) inverse opal photonic crystals.

    Science.gov (United States)

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2015-08-01

    YPO4:  Tm, Yb inverse opal photonic crystals were successfully synthesized by the colloidal crystal templates method, and the visible-infrared quantum cutting (QC) photoluminescence properties of YPO4:  Tm, Yb inverse opal photonic crystals were investigated. We obtained tetragonal phase YPO4 in all the samples when the samples sintered at 950°C for 5 h. The visible emission intensity of Tm3+ decreased significantly when the photonic bandgap was located at 650 nm under 480 nm excitation. On the contrary, the QC emission intensity of Yb3+ was enhanced as compared with the no photonic bandgap sample. When the photonic bandgap was located at 480 nm, the Yb3+ and Tm3+ light-emitting intensity weakened at the same time. We demonstrated that the energy transfer between Tm3+ and Yb3+ is enhanced by the suppression of the red emission of Tm3+. Additionally, the mechanisms for the influence of the photonic bandgap on the energy transfer process of the Tm3+, Yb3+ codoped YPO4 inverse opal are discussed.

  10. Alternative approaches of SiC & related wide bandgap materials in light emitting & solar cell applications

    Science.gov (United States)

    Wellmann, Peter; Syväjärvi, Mikael; Ou, Haiyan

    2014-03-01

    silicon oxycarbide material can provide potential applications of the Eu luminescent materials to challenging conditions like high temperatures or aggressive environments where the silica has weaknesses. In some approaches, silicon rich silicon oxide that contain silicon nanoclusters emit red to near infrared luminescence due to quantum confinement effects while luminescence at shorter wavelength is difficult due to the interplay of defects and quantum confinement effects. In addition it is applicable as low-k dielectric, etch-stop and passivation layers. It also has an optical band-gap that is smaller than that of SiO2 which may facilitate carrier injection at lower voltages that is suitable for optoelectronics. From materials perspective of emerging materials, it seems distant to consider system related issues. The future demands on communication and lighting devices require higher information flows in modernized optical devices, for example by replacing electrical interconnects with their optical counterparts and tunable backgrounds filters for integrated optics or photonics applications. However, there are materials issues related to such device performance, for example by a non-linearity, that provide the possibility for selective removal or addition of wavelengths using hetero structures in which one side of the structure enhances the light-to-dark sensitivity of long and medium wavelength channels and diminish others, and an opposite behavior in other face of the structure. Certainly materials may be applied in various innovative ways to provide new performances in devices and systems. In any materials and device evaluation, reliability issues in passivation and packaging of semiconductor device structures provide a base knowledge that may be used to evaluate new concepts. Fundamental aspects of dielectric constant, bandgap and band offsets between the valence and conduction band edges between the passivation layer and the semiconductor create a foundation for

  11. Photon Differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation...

  12. Photon Rao

    Indian Academy of Sciences (India)

    Volume 2 Issue 5 May 1997 pp 69-72 Feature Article. Molecule of the Month Molecular–Chameleon: Solvatochromism at its Iridescent Best! Photon Rao · More Details Fulltext PDF. Volume 16 Issue 12 December 2011 pp 1303-1306. Molecule of the Month - Molecular-Chameleon: Solvatochromism at its Iridescent Best!

  13. Nonlinear photoluminescence of graded band-gap Al sub x Ga sub 1 sub - sub x As solid solutions

    CERN Document Server

    Kovalenko, V F; Shutov, S V

    2002-01-01

    The dependence of the photoluminescence (PL) intensity of undoped and doped graded band-gap Al sub x Ga sub 1 sub - sub x As (x <= 0.36) solid solutions on the excitation level J (1 x 10 sup 1 sup 9 <= J <= 1 x 10 sup 2 sup 2 quantum cm sup - sup 2 s) for different values of built-in quasi-electrical field E (85 <= E <= 700 V/cm) has been studied. It is found that the dependence of the near-band-edge PL intensity I in the excitation level J at an accelerating action of the field E has a complex character. The nonlinearity of I(J) dependence is explained by contribution of the two-photon absorption of the radiating recombination in the process of its remission. The optimum range of E values (120 <= E <= 200 V/cm) providing the greatest contribution of the two-photon absorption in the reemission in undoped solid solutions is determined

  14. In-plane wavelength division de-multiplexing using photonic crystals

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Harpøth, Anders; Hede, K. K.

    We demonstrate a novel concept for in-plane coarse wavelength division de-multiplexing in integrated photonic circuits utilizing planar photonic crystal waveguides (PhCWs) fabricated in a silicon-on-insulator material. The filtering of wavelength channels is realized by shifting the cut......-off frequency of the fundamental photonic bandgap mode. The shift is obtained by modifying the size of the border holes in consecutive sections of the PhCW1. Simulations and experimental proof-of-principle of the four-channel de-multiplexer will be presented. 1A. Adibi et al., Electron. Lett. 36, 1376...

  15. Two-Photon Absorption in Organometallic Bromide Perovskites

    KAUST Repository

    Walters, Grant

    2015-07-21

    Organometallic trihalide perovskites are solution processed semiconductors that have made great strides in third generation thin film light harvesting and light emitting optoelectronic devices. Recently it has been demonstrated that large, high purity single crystals of these perovskites can be synthesized from the solution phase. These crystals’ large dimensions, clean bandgap, and solid-state order, have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW-1 at 800 nm, comparable to epitaxial single crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

  16. Three-Dimensional Self-Assembled Photonic Crystal Waveguide

    Science.gov (United States)

    Baek, Kang-Hyun

    Photonic crystals (PCs), two- or three-dimensionally periodic, artificial, and dielectric structures, have a specific forbidden band for electromagnetic waves, referred to as photonic bandgap (PBG). The PBG is analogous to the electronic bandgap in natural crystal structures with periodic atomic arrangement. A well-defined and embedded planar, line, or point defect within the PCs causes a break in its structural periodicity, and introduces a state in the PBG for light localization. It offers various applications in integrated optics and photonics including optical filters, sharp bending light guides and very low threshold lasers. Using nanofabrication processes, PCs of the 2-D slab-type and 3-D layer-by-layer structures have been investigated widely. Alternatively, simple and low-cost self-assembled PCs with full 3-D PBG, inverse opals, have been suggested. A template with face centered cubic closed packed structure, opal, may initially be built by self-assembly of colloidal spheres, and is selectively removed after infiltrating high refractive index materials into the interstitials of spheres. In this dissertation, the optical waveguides utilizing the 3-D self-assembled PCs are discussed. The waveguides were fabricated by microfabrication technology. For high-quality colloidal silica spheres and PCs, reliable synthesis, self-assembly, and characterization techniques were developed. Its theoretical and experimental demonstrations are provided and correlated. They suggest that the self-assembled PCs with PBG are feasible for the applications in integrated optics and photonics.

  17. Two-Photon Absorption in Organometallic Bromide Perovskites

    KAUST Repository

    Walters, Grant; Sutherland, Brandon R; Hoogland, Sjoerd; Shi, Dong; Comin, Riccardo; Sellan, Daniel P.; Bakr, Osman; Sargent, Edward H.

    2015-01-01

    Organometallic trihalide perovskites are solution processed semiconductors that have made great strides in third generation thin film light harvesting and light emitting optoelectronic devices. Recently it has been demonstrated that large, high purity single crystals of these perovskites can be synthesized from the solution phase. These crystals’ large dimensions, clean bandgap, and solid-state order, have provided us with a suitable medium to observe and quantify two-photon absorption in perovskites. When CH3NH3PbBr3 single crystals are pumped with intense 800 nm light, we observe band-to-band photoluminescence at 572 nm, indicative of two-photon absorption. We report the nonlinear absorption coefficient of CH3NH3PbBr3 perovskites to be 8.6 cm GW-1 at 800 nm, comparable to epitaxial single crystal semiconductors of similar bandgap. We have leveraged this nonlinear process to electrically autocorrelate a 100 fs pulsed laser using a two-photon perovskite photodetector. This work demonstrates the viability of organometallic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

  18. Transition of lasing modes in polymeric opal photonic crystal resonating cavity.

    Science.gov (United States)

    Shi, Lan-Ting; Zheng, Mei-Ling; Jin, Feng; Dong, Xian-Zi; Chen, Wei-Qiang; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2016-06-10

    We demonstrate the transition of lasing modes in the resonating cavity constructed by polystyrene opal photonic crystals and 7 wt. % tert-butyl Rhodamine B doped polymer film. Both single mode and multiple mode lasing emission are observed from the resonating cavity. The lasing threshold is determined to be 0.81  μJ/pulse for single mode lasing emission and 2.25  μJ/pulse for multiple mode lasing emission. The single mode lasing emission is attributed to photonic lasing resulting from the photonic bandgap effect of the opal photonic crystals, while the multiple mode lasing emission is assigned to random lasing due to the defects in the photonic crystals. The result would benefit the development of low threshold polymeric solid state photonic crystal lasers.

  19. Physical properties and analytical models of band-to-band tunneling in low-bandgap semiconductors

    International Nuclear Information System (INIS)

    Shih, Chun-Hsing; Dang Chien, Nguyen

    2014-01-01

    Low-bandgap semiconductors, such as InAs and InSb, are widely considered to be ideal for use in tunnel field-effect transistors to ensure sufficient on-current boosting at low voltages. This work elucidates the physical and mathematical considerations of applying conventional band-to-band tunneling models in low-bandgap semiconductors, and presents a new analytical alternative for practical use. The high-bandgap tunneling generates most at maximum field region with shortest tunnel path, whereas the low-bandgap generations occur dispersedly because of narrow tunnel barrier. The local electrical field associated with tunneling-electron numbers dominates in low-bandgap materials. This work proposes decoupled electric-field terms in the pre-exponential factor and exponential function of generation-rate expressions. Without fitting, the analytical results and approximated forms exhibit great agreements with the sophisticated forms both in high- and low-bandgap semiconductors. Neither nonlocal nor local field is appropriate to be used in numerical simulations for predicting the tunneling generations in a variety of low- and high-bandgap semiconductors

  20. Evaluation of the two-photon absorption characteristics of GaSb/GaAs quantum rings

    Energy Technology Data Exchange (ETDEWEB)

    Wagener, M. C.; Botha, J. R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Carrington, P. J. [Department of Electronic and Electrical Engineering, University College London, London (United Kingdom); Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2014-07-28

    The optical parameters describing the sub-bandgap response of GaSb/GaAs quantum rings solar cells have been obtained from photocurrent measurements using a modulated pseudo-monochromatic light source in combination with a second, continuous photo-filling source. By controlling the charge state of the quantum rings, the photoemission cross-sections describing the two-photon sub-bandgap transitions could be determined independently. Temperature dependent photo-response measurements also revealed that the barrier for thermal hole emission from the quantum rings is significantly below the quantum ring localisation energy. The temperature dependence of the sub-bandgap photo-response of the solar cell is also described in terms of the photo- and thermal-emission characteristics of the quantum rings.

  1. Photon Collider Physics with Real Photon Beams

    International Nuclear Information System (INIS)

    Gronberg, J; Asztalos, S

    2005-01-01

    Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e + e - collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two

  2. Experiment and simulation on one-dimensional plasma photonic crystals

    International Nuclear Information System (INIS)

    Zhang, Lin; Ouyang, Ji-Ting

    2014-01-01

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5 Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range

  3. Laser-induced bandgap collapse in GaAs

    Science.gov (United States)

    Siegal, Y.; Glezer, Eli N.; Huang, Li; Mazur, Eric

    1994-05-01

    We present recent time-resolved measurements of the linear dielectric constant of GaAs at 2.2 eV and 4.4 eV following femtosecond laser pulse excitation. In sharp contrast to predictions based on the widely used Drude model, the data show an interband absorption peak coming into resonance first with the 4.4 eV probe photon energy and then with the 2.2 eV probe photon energy, indicating major changes in the band structure. The time scale for these changes ranges from within 100 fs to a few picoseconds, depending on the incident pump pulse fluence.

  4. Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector

    Science.gov (United States)

    Huntington, Andrew

    2013-01-01

    The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.

  5. Device Modeling of the Performance of Cu(In,GaSe2 Solar Cells with V-Shaped Bandgap Profiles

    Directory of Open Access Journals (Sweden)

    Shou-Yi Kuo

    2014-01-01

    Full Text Available The effect of Cu(In,GaSe2 (CIGS with V-shaped bandgap on device performance is investigated in detail. A series of Ga/(In+Ga ratio are set to study the influence of V-shaped bandgap profile on the electricity of CIGS thin film solar cells. The modeling of device current density-voltage (J-V curve and bandgap grading profile corresponded well to measurement results. Detailed characteristic and modeling results show that an increased gradient of bandgap from valley to the buffer layer CdS will result in a barrier and lead to an enhanced recombination in the valley. This phenomenon can be modified by the back electric field resulting from a gradient bandgap from valley (bandgap minimum to the Mo back contact. These results indicate CIGS-based solar cells can achieve higher performance by optimizing the V-shaped bandgap profile.

  6. Simulation of push-pull inverter using wide bandgap devices

    Science.gov (United States)

    Al-badri, Mustafa; Matin, Mohammed A.

    2016-09-01

    This paper discusses the use of wide bandgap devices (SiC-MOSFET) in the design of a push-pull inverter which provides inexpensive low power dc-ac inverters. The parameters used were 1200V SiC MOSFET(C2M0040120D) made by power company ROHM. This modeling was created using parameters that were provided from a device datasheet. The spice model is provided by this company to study the effect of adding this component on push-pull inverter ordinary circuit and compared results between SiC MOSFET and silicon MOSFET (IRFP260M). The results focused on Vout and Vmos stability as well as on output power and MOSFET power loss because it is a very crucial aspect on DC-AC inverter design. These results are done using the National Instrument simulation program (Multisim 14). It was found that power loss is better in the 12 and 15 vdc inverter. The Vout in the SIC MOSFET circuit shows more stability in the high current low resistance load in comparison to the Silicon MOSFET circuit and this will improve the overall performance of the circuit.

  7. Angle-dependent bandgap engineering in gated graphene superlattices

    Energy Technology Data Exchange (ETDEWEB)

    García-Cervantes, H.; Sotolongo-Costa, O. [Centro de Investigación en Ciencias, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Gaggero-Sager, L. M. [CIICAp, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Naumis, G. G. [Instituto Física, Depto. de Física-Química, Universidad Nacional Autónoma de México (UNAM). Apdo. Postal 20-364, 01000, México D.F., México (Mexico); Rodríguez-Vargas, I., E-mail: isaac@fisica.uaz.edu.mx [Centro de Investigación en Ciencias, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac., México (Mexico)

    2016-03-15

    Graphene Superlattices (GSs) have attracted a lot of attention due to its peculiar properties as well as its possible technological implications. Among these characteristics we can mention: the extra Dirac points in the dispersion relation and the highly anisotropic propagation of the charge carriers. However, despite the intense research that is carried out in GSs, so far there is no report about the angular dependence of the Transmission Gap (TG) in GSs. Here, we report the dependence of TG as a function of the angle of the incident Dirac electrons in a rather simple Electrostatic GS (EGS). Our results show that the angular dependence of the TG is intricate, since for moderated angles the dependence is parabolic, while for large angles an exponential dependence is registered. We also find that the TG can be modulated from meV to eV, by changing the structural parameters of the GS. These characteristics open the possibility for an angle-dependent bandgap engineering in graphene.

  8. Angle-dependent bandgap engineering in gated graphene superlattices

    International Nuclear Information System (INIS)

    García-Cervantes, H.; Sotolongo-Costa, O.; Gaggero-Sager, L. M.; Naumis, G. G.; Rodríguez-Vargas, I.

    2016-01-01

    Graphene Superlattices (GSs) have attracted a lot of attention due to its peculiar properties as well as its possible technological implications. Among these characteristics we can mention: the extra Dirac points in the dispersion relation and the highly anisotropic propagation of the charge carriers. However, despite the intense research that is carried out in GSs, so far there is no report about the angular dependence of the Transmission Gap (TG) in GSs. Here, we report the dependence of TG as a function of the angle of the incident Dirac electrons in a rather simple Electrostatic GS (EGS). Our results show that the angular dependence of the TG is intricate, since for moderated angles the dependence is parabolic, while for large angles an exponential dependence is registered. We also find that the TG can be modulated from meV to eV, by changing the structural parameters of the GS. These characteristics open the possibility for an angle-dependent bandgap engineering in graphene.

  9. High-Temperature, Wirebondless, Ultracompact Wide Bandgap Power Semiconductor Modules

    Science.gov (United States)

    Elmes, John

    2015-01-01

    Silicon carbide (SiC) and other wide bandgap semiconductors offer great promise of high power rating, high operating temperature, simple thermal management, and ultrahigh power density for both space and commercial power electronic systems. However, this great potential is seriously limited by the lack of reliable high-temperature device packaging technology. This Phase II project developed an ultracompact hybrid power module packaging technology based on the use of double lead frames and direct lead frame-to-chip transient liquid phase (TLP) bonding that allows device operation up to 450 degC. The new power module will have a very small form factor with 3-5X reduction in size and weight from the prior art, and it will be capable of operating from 450 degC to -125 degC. This technology will have a profound impact on power electronics and energy conversion technologies and help to conserve energy and the environment as well as reduce the nation's dependence on fossil fuels.

  10. Inverse opal photonic crystal of chalcogenide glass by solution processing.

    Science.gov (United States)

    Kohoutek, Tomas; Orava, Jiri; Sawada, Tsutomu; Fudouzi, Hiroshi

    2011-01-15

    Chalcogenide opal and inverse opal photonic crystals were successfully fabricated by low-cost and low-temperature solution-based process, which is well developed in polymer films processing. Highly ordered silica colloidal crystal films were successfully infilled with nano-colloidal solution of the high refractive index As(30)S(70) chalcogenide glass by using spin-coating method. The silica/As-S opal film was etched in HF acid to dissolve the silica opal template and fabricate the inverse opal As-S photonic crystal. Both, the infilled silica/As-S opal film (Δn ~ 0.84 near λ=770 nm) and the inverse opal As-S photonic structure (Δn ~ 1.26 near λ=660 nm) had significantly enhanced reflectivity values and wider photonic bandgaps in comparison with the silica opal film template (Δn ~ 0.434 near λ=600 nm). The key aspects of opal film preparation by spin-coating of nano-colloidal chalcogenide glass solution are discussed. The solution fabricated "inorganic polymer" opal and the inverse opal structures exceed photonic properties of silica or any organic polymer opal film. The fabricated photonic structures are proposed for designing novel flexible colloidal crystal laser devices, photonic waveguides and chemical sensors. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Multi-fidelity machine learning models for accurate bandgap predictions of solids

    International Nuclear Information System (INIS)

    Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab

    2016-01-01

    Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned model that enables low-cost accurate predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelity quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.

  12. Synthesis and characterization of a low bandgap conjugated polymer for bulk heterojunction photovoltaic cells

    NARCIS (Netherlands)

    Dhanabalan, A.; Duren, van J.K.J.; Hal, van P.A.; Dongen, van J.L.J.; Janssen, R.A.J.

    2001-01-01

    Low optical bandgap conjugated polymers may improve the efficiency of organic photovoltaic devices by increasing the absorption in the visible and near infrared region of the solar spectrum. Here we demonstrate that condensation polymerization of

  13. Improved chemical stability and cyclability in Li2S–P2S5–P2O5–ZnO composite electrolytes for all-solid-state rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Hayashi, Akitoshi; Muramatsu, Hiromasa; Ohtomo, Takamasa; Hama, Sigenori; Tatsumisago, Masahiro

    2014-01-01

    Highlights: • Chemical stability in air of Li 2 S–P 2 S 5 –P 2 O 5 –ZnO composite electrolytes was examined. • A partial substitution of P 2 O 5 for P 2 S 5 decreased the rate of H 2 S generation. • The addition of ZnO to the glasses reduced the amount of H 2 S. • All-solid-state lithium cells using the developed composite electrolytes exhibited good cyclability. -- Abstract: Sulfide glasses with high Li + ion conductivity are promising solid electrolytes for all-solid-state rechargeable lithium batteries. This study specifically examined the chemical stability of Li 2 S–P 2 S 5 -based glass electrolytes in air. Partial substitution of P 2 O 5 for P 2 S 5 decreased the rate of H 2 S generation from glass exposed to air. The addition of ZnO to the Li 2 S–P 2 S 5 –P 2 O 5 glasses as a H 2 S absorbent reduced the H 2 S gas release. A composite electrolyte prepared from 90 mol% of 75Li 2 S⋅21P 2 S 5 ⋅4P 2 O 5 (mol%) glass and 10 mol% ZnO was applied to all-solid-state cells. The all-solid-state In/LiCoO 2 cell with the composite electrolyte showed good cyclability as a lithium secondary battery

  14. Linewidth of Cyclotron Absorption in Band-Gap Graphene: Relaxation Time Approximation vs. Monte Carlo Method

    OpenAIRE

    S.V. Kryuchkov; E.I. Kukhar’; D.V. Zav’yalov

    2015-01-01

    The power of the elliptically polarized electromagnetic radiation absorbed by band-gap graphene in presence of constant magnetic field is calculated. The linewidth of cyclotron absorption is shown to be non-zero even if the scattering is absent. The calculations are performed analytically with the Boltzmann kinetic equation and confirmed numerically with the Monte Carlo method. The dependence of the linewidth of the cyclotron absorption on temperature applicable for a band-gap graphene in the...

  15. Semi-transparent polymer solar cells with excellent sub-bandgap transmission for third generation photovoltaics

    KAUST Repository

    Beiley, Zach M.

    2013-10-07

    Semi-transparent organic photovoltaics are of interest for a variety of photovoltaic applications, including solar windows and hybrid tandem photovoltaics. The figure shows a photograph of our semi-transparent solar cell, which has a power conversion efficiency of 5.0%, with an above bandgap transmission of 34% and a sub-bandgap transmission of 81%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Photon absorptiometry

    International Nuclear Information System (INIS)

    Valkema, R.; Blokland, J.A.K.; Papapoulos, S.E.; Bijvoet, O.L.M.; Pauwels, E.K.J.

    1989-01-01

    Osteoporosis is a significant health problem in the western world, with important medical, social and economical consequences. Prevention and treatment require reliable methods for in vivo monitoring of the bone mineral content (BMC) and its change in time. This paper presents an overview of currently used radiological methods, based on photon absorptiometry, and their clinical applications. With recent methods based on dual energy X-ray absorptiometry accurate and precise measurements of axial BMC can be obtained. Whether this improvements allows reliable detection of small changes in BMC remains to be investigated. (Author). 95 refs.; 1 tab

  17. Radiation resistance of wide-bandgap semiconductor power transistors

    Energy Technology Data Exchange (ETDEWEB)

    Hazdra, Pavel; Popelka, Stanislav [Department of Microelectronics, Czech Technical University in Prague (Czech Republic)

    2017-04-15

    Radiation resistance of state-of-the-art commercial wide-bandgap power transistors, 1700 V 4H-SiC power MOSFETs and 200 V GaN HEMTs, to the total ionization dose was investigated. Transistors were irradiated with 4.5 MeV electrons with doses up to 2000 kGy. Electrical characteristics and introduced defects were characterized by current-voltage (I-V), capacitance-voltage (C-V), and deep level transient spectroscopy (DLTS) measurements. Results show that already low doses of 4.5 MeV electrons (>1 kGy) cause a significant decrease in threshold voltage of SiC MOSFETs due to embedding of the positive charge into the gate oxide. On the other hand, other parameters like the ON-state resistance are nearly unchanged up to the dose of 20 kGy. At 200 kGy, the threshold voltage returns back close to its original value, however, the ON-state resistance increases and transconductance is lowered. This effect is caused by radiation defects introduced into the low-doped drift region which decrease electron concentration and mobility. GaN HEMTs exhibit significantly higher radiation resistance. They keep within the datasheet specification up to doses of 2000 kGy. Absence of dielectric layer beneath the gate and high concentration of carriers in the two dimensional electron gas channel are the reasons of higher radiation resistance of GaN HEMTs. Their degradation then occurs at much higher doses due to electron mobility degradation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. II-VI Narrow-Bandgap Semiconductors for Optoelectronics

    Science.gov (United States)

    Baker, Ian

    The field of narrow-gap II-VI materials is dominated by the compound semiconductor mercury cadmium telluride, (Hg1-x Cd x Te or MCT), which supports a large industry in infrared detectors, cameras and infrared systems. It is probably true to say that HgCdTe is the third most studied semiconductor after silicon and gallium arsenide. Hg1-x Cd x Te is the material most widely used in high-performance infrared detectors at present. By changing the composition x the spectral response of the detector can be made to cover the range from 1 μm to beyond 17 μm. The advantages of this system arise from a number of features, notably: close lattice matching, high optical absorption coefficient, low carrier generation rate, high electron mobility and readily available doping techniques. These advantages mean that very sensitive infrared detectors can be produced at relatively high operating temperatures. Hg1-x Cd x Te multilayers can be readily grown in vapor-phase epitaxial processes. This provides the device engineer with complex doping and composition profiles that can be used to further enhance the electro-optic performance, leading to low-cost, large-area detectors in the future. The main purpose of this chapter is to describe the applications, device physics and technology of II-VI narrow-bandgap devices, focusing on HgCdTe but also including Hg1-x Mn x Te and Hg1-x Zn x Te. It concludes with a review of the research and development programs into third-generation infrared detector technology (so-called GEN III detectors) being performed in centers around the world.

  19. Overcoming the Photovoltage Plateau in Large Bandgap Perovskite Photovoltaics.

    Science.gov (United States)

    Rajagopal, Adharsh; Stoddard, Ryan J; Jo, Sae Byeok; Hillhouse, Hugh W; Jen, Alex K-Y

    2018-05-09

    Development of large bandgap (1.80-1.85 eV E g ) perovskite is crucial for perovskite-perovskite tandem solar cells. However, the performance of 1.80-1.85 eV E g perovskite solar cells (PVKSCs) are significantly lagging their counterparts in the 1.60-1.75 eV E g range. This is because the photovoltage ( V oc ) does not proportionally increase with E g due to lower optoelectronic quality of conventional (MA,FA,Cs)Pb(I,Br) 3 and results in a photovoltage plateau ( V oc limited to 80% of the theoretical limit for ∼1.8 eV E g ). Here, we incorporate phenylethylammonium (PEA) in a mixed-halide perovskite composition to solve the inherent material-level challenges in 1.80-1.85 eV E g perovskites. The amount of PEA incorporation governs the topography and optoelectronic properties of resultant films. Detailed structural and spectroscopic characterization reveal the characteristic trends in crystalline size, orientation, and charge carrier recombination dynamics and rationalize the origin of improved material quality with higher luminescence. With careful interface optimization, the improved material characteristics were translated to devices and V oc values of 1.30-1.35 V were achieved, which correspond to 85-87% of the theoretical limit. Using an optimal amount of PEA incorporation to balance the increase in V oc and the decrease in charge collection, a highest power conversion efficiency of 12.2% was realized. Our results clearly overcome the photovoltage plateau in the 1.80-1.85 eV E g range and represent the highest V oc achieved for mixed-halide PVKSCs. This study provides widely translatable insights, an important breakthrough, and a promising platform for next-generation perovskite tandems.

  20. Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge

    Energy Technology Data Exchange (ETDEWEB)

    Inaoka, Takeshi, E-mail: inaoka@phys.u-ryukyu.ac.jp; Furukawa, Takuro; Toma, Ryo; Yanagisawa, Susumu [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan)

    2015-09-14

    By means of a hybrid density-functional method, we investigate the tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. We consider [001], [111], and [110] uniaxial tensility and (001), (111), and (110) biaxial tensility. Under the condition of no normal stress, we determine both normal compression and internal strain, namely, relative displacement of two atoms in the primitive unit cell, by minimizing the total energy. We identify those strain types which can induce the band-gap transition, and evaluate the critical strain coefficient where the gap transition occurs. Either normal compression or internal strain operates unfavorably to induce the gap transition, which raises the critical strain coefficient or even blocks the transition. We also examine how each type of tensile strain decreases the band-gap energy, depending on its orientation. Our analysis clearly shows that synergistic operation of strain orientation and band anisotropy has a great influence on the gap transition and the gap energy.