Home About us Contact
|
Home About us Contact | ||
|
|
||
High Electrical Conductivity (high + electrical_conductivity)
Selected AbstractsChemInform Abstract: AA,2Rh6O12: A New Family of Rhodium Oxides Exhibiting High Thermopower Coupled with High Electrical Conductivity.CHEMINFORM, Issue 25 2009Hiroshi Mizoguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Microstructure and Microfabrication Considerations for Self-Supported On-Chip Ultra-Thin Micro-Solid Oxide Fuel Cell MembranesFUEL CELLS, Issue 5 2009B.-K. Lai Abstract La0.6Sr0.4Co0.8Fe0.2O3,,,, (LSCF) has been sputtered on bare Si and Si3N4 and yttria-stabilised zirconia (YSZ) thin films to investigate annealing temperature- and thickness-dependent microstructure and functional properties, as well as their implications for designing failure-resistant micro-solid oxide fuel cell (,SOFC) membranes. The LSCF thin films crystallise in the 400,450,°C range; however, after annealing in the 600,700,°C range, cracks are observed. The formation of cracks is also thickness-dependent. High electrical conductivity, ,520,Scm,1 at 600,°C, and low activation energy, ,0.13,eV, in the 400,600,°C range, are still maintained for LSCF films as thin as 27,nm. Based on these studies, a strong correlation between microstructure and electrical conductivity has been observed and an annealing temperature-thickness design space that is complementary to temperature-stress design space has been proposed for designing reliable membranes using sputtered LSCF thin films. Microfabrication approaches that maintain the highest possible surface and interface quality of heterostructured membranes have been carefully examined. By taking advantage of the microstructure, microfabrication and geometrical structural considerations, we were able to successfully fabricate large-area, self-supported membranes. These results are also relevant to conventional or grid-supported SOFC membranes using ultrathin nanocrystalline cathodes and ,SOFCs using cathode thin films other than LSCF. [source] Combined seismic tomographic and ultrashallow seismic reflection study of an Early Dynastic mastaba, Saqqara, EgyptARCHAEOLOGICAL PROSPECTION, Issue 4 2005Mohamed Metwaly Abstract Mastabas were large rectangular structures built for the funerals and burials of the earliest Pharaohs. One such mastaba was the basic building block that led to the first known stone pyramid, the,>4600-year old Step Pyramid within the Saqqara necropolis of Egypt. We have tested a number of shallow geophysical techniques for investigating in a non-invasive manner the subsurface beneath a large Early Dynastic mastaba located close to the Step Pyramid. After discovering that near-surface sedimentary rocks with unusually high electrical conductivities precluded the use of the ground-penetrating radar method, a very high-resolution seismic data set was collected along a profile that extended the 42.5,m length of the mastaba. A sledgehammer source was used every 0.2,m and the data were recorded using a 48-channel array of single geophones spaced at 0.2,m intervals. Inversions of the direct- and refracted-wave travel times provided P-wave velocity tomograms of the shallow subsurface, whereas relatively standard processing techniques yielded a high-fold (50,80) ultrashallow seismic reflection section. The tomographic and reflection images were jointly interpreted in terms of loose sand and friable limestone layers with low P-wave velocities of 150,650,m,s,1 overlying consolidated limestone and shale with velocities,>,1500,m,s,1. The sharp contact between the low- and high-velocity regimes was approximately horizontal at a depth of ca. 2,m. This contact was the source of a strong seismic reflection. Above this contact, the velocity tomogram revealed moderately high velocities at the surface location of a friable limestone outcrop and two low-velocity blocks that probably outlined sand-filled shafts. Below the contact, three regularly spaced low velocity blocks probably represented tunnels and/or subsurface chambers. Copyright © 2005 John Wiley & Sons, Ltd. [source] Physical properties of Dy and La doped SnO2 thin films prepared by a cost effective vapour deposition techniqueCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2006J. Joseph Abstract Stannous oxide (SnO2) thin film is one of the most widely used n-type transparent semi-conductor films in electronics, electro-optics and solar energy conversion. By achieving controlled non-stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO2 thin films. Dy and La doped SnO2 thin films have been prepared by a cost effective vapour deposition technique. The structural, photo-electronic, optical and electrical properties of the doped and undoped films were studied. The results of X-ray Diffraction studies reveals the polycrystalline nature of the films with preferential orientation along the (101), (211) and (301) planes and their average grain size variation for different deposition temperature. Photoconductivity and Photovoltaic studies of the films were also performed. The optical properties of these films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on Dy doping and decreased on La doping. The band gap, refractive index and thickness of the films were calculated from U-V transmittance and Absorption graphs. The optical band gap of undoped film is found to be 4.08 eV, but on doping it shifts to lower energies and then increases on increasing the concentration of both dopants. Its electrical parameters such as sheet resistance, resistivity, mobility, Hall coefficient, and carrier concentration were determined by Four Probe, Van der Pauw and Hall Probe method. On doping with Dy, carrier conversion takes place from n-type to p-type and p-conductivity dominates. On La doping no carrier conversion takes place but resistivity decreases. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Poly(neutral red): Electrosynthesis, Characterization, and Application as a Redox MediatorELECTROANALYSIS, Issue 12 2008Rasa Pauliukaite Abstract The synthesis by electropolymerization, the characterization, and applications of poly(neutral red) (PNR), including as a redox mediator, are reviewed. PNR's high electrical conductivity and its redox characteristics have led to special applications of the polymer, and it has been used for the development of electrochemical and optical sensors. Moreover, the attractive properties of PNR allow it to be applied in the development of electrochemical biosensors. Future perspectives are indicated. [source] Nanodiamond Thin Film Electrodes: Metal Electro-Deposition and Stripping ProcessesELECTROANALYSIS, Issue 3 2003Hian, Lau Chi Abstract The properties of a nanodiamond thin film deposit formed on titanium substrates in a microwave-plasma enhanced CVD process, are investigated for applications in electroanalysis. The nanodiamond deposit consists of intergrown nano-sized platelets of diamond with a high sp2 carbon content giving it high electrical conductivity and electrochemical reactivity. Nanodiamond thin film electrodes (of approximately 2,,m thickness) are characterized by electron microscopy and electrochemical methods. First, for a reversible one electron redox system, Ru(NH3)63+/2+, nanodiamond is shown to give well-defined diffusion controlled voltammetric responses. Next, metal deposition processes are shown to proceed on nanodiamond with high reversibility and high efficiency compared to processes reported on boron-doped diamond. The nucleation of gold is shown to be facile at edge sites, which are abundant on the nanodiamond surface. For the deposition and stripping of both gold and copper, a stripping efficiency (the ratio of electro-dissolution charge to electro-deposition charge) of close to unity is detected even at low concentrations of analyte. The effect of thermal annealing in air is shown to drastically modify the electrode characteristics probably due to interfacial oxidation, loss of active sp2 sites, and loss of conductivity. [source] Copper, Cobalt and Platinum Complexes with Dithiothiophene-Based LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2005Dulce Belo Abstract The preparation and characterisation of new thiophenedithiolate complexes of Cu, Co and Pt with the ligands ,-tpdt and tpdt (,-tpdt = 2,3-thiophenedithiolate, tpdt = 3,4-thiophenedithiolate) is reported. The Co and Pt complexes present regular square-planar coordination geometry and low oxidation potentials when compared with complexes with simpler ligands, but their monoanionic state is found to be rather unstable. The Co(tpdt)2 complex can be isolated both in the monoanionic and dianionic states as a stable compound but the Co(,-tpdt)2 and the Pt complexes can be obtained only in the dianionic state, while their monoanionic state is unstable. The Co and Pt complexes can, however, be easily oxidised to the neutral state, giving a fine-powdered microcrystalline material without high electrical conductivity. With Cu only a less frequent geometry based on a tetrametallic CuI cluster and three ligands is observed as [Cu4(,-tpdt)3]2, and [Cu4(tpdt)3]2,. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] A Reusable Interface Constructed by 3-Aminophenylboronic Acid-Functionalized Multiwalled Carbon Nanotubes for Cell Capture, Release, and CytosensingADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Xue Zhong Abstract A newly developed electrochemical cell sensor for the determination of K562 leukemia cells using 3-aminophenylboronic acid (APBA)-functionalized multiwalled carbon nanotubes (MWCNTs) films is demonstrated. The films are generated by the covalent coupling between the NH2 groups in APBA and the COOH group in the acid-oxidized MWCNTs. As a result of the sugar-specific affinity interactions, the K562 leukemia cells are firmly bound to the APBA-functionalized MWCNTs film via boronic acid groups. Compared to electropolymerized APBA films, the presence of MWCNTs not only provides abundant boronic acid domains for cell capture, their high electrical conductivity also makes the film suitable for electrochemical sensing applications. The resulting modified electrodes are tested as cell detection sensors. This work presents a promising platform for effective cell capture and constructing reusable cytosensors. [source] High Mechanical Performance Composite Conductor: Multi-Walled Carbon Nanotube Sheet/Bismaleimide NanocompositesADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Qunfeng Cheng Abstract Multi-walled carbon nanotube (MWNT)-sheet-reinforced bismaleimide (BMI) resin nanocomposites with high concentrations (,60,wt%) of aligned MWNTs are successfully fabricated. Applying simple mechanical stretching and prepregging (pre-resin impregnation) processes on initially randomly dispersed, commercially available sheets of millimeter-long MWNTs leads to substantial alignment enhancement, good dispersion, and high packing density of nanotubes in the resultant nanocomposites. The tensile strength and Young's modulus of the nanocomposites reaches 2,088,MPa and 169,GPa, respectively, which are very high experimental results and comparable to the state-of-the-art unidirectional IM7 carbon-fiber-reinforced composites for high-performance structural applications. The nanocomposites demonstrate unprecedentedly high electrical conductivity of 5,500,S cm,1 along the alignment direction. Such unique integration of high mechanical properties and electrical conductance opens the door for developing polymeric composite conductors and eventually structural composites with multifunctionalities. New fracture morphology and failure modes due to self-assembly and spreading of MWNT bundles are also observed. [source] High-Performance Photoresponsive Organic Nanotransistors with Single-Layer Graphenes as Two-Dimensional ElectrodesADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Yang Cao Abstract Graphene behaves as a robust semimetal with the high electrical conductivity stemming from its high-quality tight two-dimensional crystallographic lattice. It is therefore a promising electrode material. Here, a general methodology for making stable photoresponsive field effect transistors, whose device geometries are comparable to traditional macroscopic semiconducting devices at the nanometer scale, using cut graphene sheets as 2D contacts is detailed. These contacts are produced through oxidative cutting of individual 2D planar graphene by electron beam lithography and oxygen plasma etching. Nanoscale organic transistors based on graphene contacts show high-performance FET behavior with bulk-like carrier mobility, high on/off current ratio, and high reproducibility. Due to the presence of photoactive molecules, the devices display reversible changes in current when they are exposed to visible light. The calculated responsivity of the devices is found to be as high as ,8.3,A,W,1. This study forms the basis for making new types of ultrasensitive molecular devices, thus initiating broad research interest in the field of nanoscale/molecular electronics. [source] Electromagnetic fields in a steel-cased boreholeGEOPHYSICAL PROSPECTING, Issue 1 2005Ki Ha Lee ABSTRACT The development of an electromagnetic numerical modelling scheme for a magnetic dipole in an arbitrary casing segment in an inhomogeneous conductivity background has been difficult, due to the very high electrical conductivity and magnetic permeability contrasts between the steel casing and the background medium. To investigate the effect of steel casing efficiently, we have developed an accurate but simple finite-element modelling scheme to simulate electromagnetic fields in a medium of cylindrically symmetric conductivity structures. In order to preserve the cylindrical symmetry in the resulting electromagnetic fields, a horizontal loop current source is used throughout. One of the main advantages of the approach is that the problem is scalar when formulated using the azimuthal electric field, even if the casing is both electrically conductive and magnetically permeable. Field calculations have been made inside the cased borehole as well as in another borehole which is not cased. Careful analyses of the numerical modelling results indicate that the anomaly observed in a cross-borehole configuration is sensitive enough to be used for tomographic imaging. [source] Solvothermal Synthesis, Cathodoluminescence, and Field-Emission Properties of Pure and N-Doped ZnO NanobulletsADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Ujjal K. Gautam Abstract Homogenous crystallization in solution, in the absence of external influences, is expected to lead to growth that is symmetric at least in two opposite facets. Such was not the case when we attempted to synthesize ZnO nanostructures by employing a solvothermal technique. The reaction product, instead, consisted of bullet-shaped tiny single crystals with an abrupt hexagonal base and a sharp tip. A careful analysis of the product and the intermediate states of the synthesis reveals that one of the reaction intermediates with sheet-like morphology acts as a self-sacrificing template and induces such unexpected and novel growth. The synthesis was further extended to dope the nanobullets with nitrogen as previous studies showed this can induce p-type behavior in ZnO, which is technologically complementary to the naturally occurring n-type ZnO. Herein, a soft-chemical approach is used for the first time for this purpose, which is otherwise accomplished with high-temperature techniques. Cathodoluminesce (CL) investigations reveal stable optical behavior within a pure nanobullet. On the other hand, the CL spectra derived from the surfaces and the cores of the doped samples are different, pointing at a N-rich core. Finally, even though N-doped ZnO is known to have high electrical conductivity, the study now demonstrates that the field-emission properties of ZnO can also be greatly enhanced by means of N doping. [source] Groundwater quality in the semi-arid region of the Chahardouly basin, West IranHYDROLOGICAL PROCESSES, Issue 16 2008A. Taheri Tizro Abstract Chahardouly basin is located in the western part of Iran and is characterized by semi-arid climatic conditions and scarcity in water resources. The main aquifer systems are developed within alluvial deposits. The availability of groundwater is rather erratic owing to the occurrence of hard rock formation and a saline zone in some parts of the area. The aquifer systems of the area show signs of depletion, which have taken place in recent years due to a decline in water levels. Groundwater samples collected from shallow and deep wells were analysed to examine the quality characteristics of groundwater. The major ion chemistry of groundwater is dominated by Ca2+ and HCO3,, while higher values of total dissolved solids (TDS) in groundwater are associated with high concentrations of all major ions. An increase in salinity is recorded in the down-gradient part of the basin. The occurrence of saline groundwater, as witnessed by the high electrical conductivity (EC), may be attributed to the long residence time of water and the dissolution of minerals, as well as evaporation of rainfall and irrigation return flow. Based on SAR values and sodium content (%Na), salinity appears to be responsible for the poor groundwater quality, rendering most of the samples not suitable for irrigation use. Copyright © 2007 John Wiley & Sons, Ltd. [source] Thermoelectric Performance of Epitaxial Thin Films of Layered Cobalt Oxides Grown by Reactive Solid-Phase Epitaxy with Topotactic Ion-Exchange MethodsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2007Kenji Sugiura This article reviews high-quality epitaxial film growth of layered cobalt oxides by reactive solid-phase epitaxy (R-SPE) with topotactic ion-exchange methods. Epitaxial film of Na0.8CoO2 was grown on a (0001)-oriented ,-Al2O3 substrate by R-SPE using CoO film as the starting material. The Na0.8CoO2 epitaxial films were converted into high-quality epitaxial films of Sr0.32Na0.21CoO2 and [Ca2CoO3]xCoO2 by topotactic ion-exchange methods. The Sr0.32Na0.21CoO2 film exhibited better stability against moisture than that of the Na0.8CoO2 film, while it retained the good thermoelectric properties of Na0.8CoO2. The [Ca2CoO3]xCoO2 film exhibited a high electrical conductivity of 2.95 × 102 S/cm and a large Seebeck coefficient of +125 ,V/K at 300 K. [source] Generating heat from conducting polypyrrole-coated PET fabricsADVANCES IN POLYMER TECHNOLOGY, Issue 3 2005Akif Kaynak Abstract Heating effects in polypyrrole-coated polyethyleneterephthalate (PET)-Lycra® fabrics were studied. Chemical synthesis was employed to coat the PET fabrics by polypyrrole using ferric chloride as oxidant and antraquinone- 2-sulfonic acid (AQSA) and naphthalene sulfonic acid (NSA) as dopants. The coated fabrics exhibited reasonable electrical stability, possessed high electrical conductivity, and were effective in heat generation. Surface resistance of polypyrrole-coated fabrics ranged from approximately 150 to 500 ,/square. Different connections between conductive fabrics and the power source were examined. When subjected to a constant voltage of 24 V, the current transmitted through the fabric decreased about 10% in 72 h. An increase in resistance of conductive fabrics subjected to constant voltage was observed. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24: 194,207, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20040 [source] Emulsion synthesis of nanoparticles containing PEDOT using conducting polymeric surfactant: Synergy for colloid stability and intercalation dopingJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2008Chi-an Dai Abstract Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is a widely used conductive aqueous dispersion synthesized by using emulsion polymerization method. To further enhance its solution processability and conductivity of PEDOT derivatives, we proposed to replace the nonconductive PSS with conductive poly[2-(3thienyl)-ethoxy-4-butylsulfonate] (PTEB) as surfactant for the emulsion polymerization of PEDOT. The reaction involved colloid stabilization and doping in one step, and yielded PEDOT:PTEB composite nanoparticles with high electrical conductivity. Contrary to its counterpart containing nonconductive surfactant, PEDOT: PTEB showed increasing film conductivity with increasing PTEB concentration. The result demonstrates the formation of efficient electrical conduction network formed by the fully conductive latex nanoparticles. The addition of PTEB for EDOT polymerization significantly reduced the size of composite particles, formed stable spherical particles, enhanced thermal stability, crystallinity, and conductivity of PEDOT:PTEB composite. Evidence from UV,VIS and FTIR measurement showed that strong molecular interaction between PTEB and PEDOT resulted in the doping of PEDOT chains. X-ray analysis further demonstrated that PTEB chains were intercalated in the layered crystal structure of PEDOT. The emulsion polymerization of EDOT using conducting surfactant, PTEB demonstrated the synergistic effect of PTEB on colloid stability and intercalation doping of PEDOT during polymerization resulting in significant conductivity improvement of PEDOT composite nanoparticles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2536,2548, 2008 [source] Sintering Behavior and Conductivity Study of Yttrium-Doped BaCeO3,BaZrO3 Solid Solutions Using ZnO AdditivesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2009He Wang The effect of ZnO on the crystal structure, sintering behavior, and electrical conductivity of yttrium-doped BaCeO3,BaZrO3 was investigated by unfixing or fixing the yttrium content noted as BaCe0.5Zr0.3Y0.2,xZnxO2.9,0.5x and BaCe0.5Zr0.3Y0.2O2.9+yZnO, respectively. Studies on the two series revealed that BaO·ZnO eutectic, rather than ZnO, was responsible for the sintering densification. For BaCe0.5Zr0.3Y0.2,xZnxO2.9,0.5x, the evaporation of ZnO·BaO eutectic was observed after sintering at 1300°C for 10 h, and few impurities were detected by XRD with x<0.20. For BaCe0.5Zr0.3Y0.2O2.9+yZnO, the concomitant loss of BaO with ZnO caused A-site deficiency and led to impurities of Y2O3 for y=0.08 and 0.14, and Y2BaZnO5 for y=0.20 during the sintering. For both series, ZnO enhanced the relative density, which was above 97% with x or y varying from 0.02 to 0.08. Energy-dispersive X-ray spectroscopy analysis revealed that ZnO hardly entered the perovskite phase. The conductivity study also suggested that ZnO did not serve as a dopant and that yttrium content was essential for sustaining a high ionic conduction. Excessive ZnO was especially detrimental to the grain boundary conduction and thus lowered the total electrical conduction. The optimized composition of BaCe0.5Zr0.3Y0.2O2.9+0.04ZnO has been obtained, with both a high relative density (,98.5%) and a high electrical conductivity (1.35 × 10,2 S/cm at 600°C). [source] Electrical Conductivity of Submicrometer Gadolinia-Doped Ceria Sintered at 1000°C Using Precipitation-Synthesized Nanocrystalline PowdersJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2008Pandurangan Muralidharan A simple synthetic strategy has been implemented to obtain low-temperature sintered fine grain size gadolinia-doped ceria, Ce0.9Gd0.1O1.95, (CGO) electrolyte pellets with a high density using weakly agglomerated particles of calcined nanopowders synthesized by a homogeneous precipitation process. The precipitants used were diethylamine (DEA process) and ammonium hydroxide in neutral precipitation (NP process). X-ray diffraction patterns revealed the single-phase crystalline CGO of a fluorite-type structure. The crystalline powder was directly synthesized from solution by the DEA process at room temperature, whereas the NP process powder was crystallized upon hydrothermal treatment at an elevated temperature. Transmission electron microscopy images showed homogeneously dispersed spherical-shaped particles of ,5 nm size for nanopowders calcined at 300°C for 4 h. A high densification range from ,96% to 99% of the theoretical was achieved for the nonconventionally low-temperature sintered pellets at 1000°C from weakly bonded particles of CGO nanopowders calcined at 300°C for 4 h without any sintering aid. The dense CGO pellets sintered at 1000°C for 4 h with an average grain size of ,150,300 nm exhibited a promising high electrical conductivity of 2.03 × 10,2 S/cm (DEA process) and 2.17 × 10,2 S/cm (NP process), measured at 650°C, and low activation energy Ea. The electrical conductivities of fine grain size low-temperature sintered CGO pellets are comparable with the literature reports of sintered pellets using sintering aids, and high-temperature sintered CGO pellets above 1300°C with a larger grain size. [source] Conductive thin film formation onto radiation grafted polymeric surfaces using electroless plating techniquePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9 2009Amr El-Hag Ali Abstract Surface modification of polypropylene films (PP) was carried out via radiation induced graft copolymerization of 4-vinyl pyridine (4VP) and acrylamide (AAm) to enhance the adhesion ability of the PP surface for electroless deposition of copper. Factors affecting the grafting process such as suitable solvent, comonomer composition and concentration and irradiation dose were optimized. The grafted films produced were characterized by studying their Fourier-transform infrared (FTIR) spectra and thermal stability. The grafted films were copper-plated by electroless deposition using Pd as the catalyst to initiate the redox reaction. The influence of catalytic activation method parameters on the plating rate were studied. Scanning electron microscopy revealed a dense and void-free copper deposited film. The adhesion of the deposited copper film to the modified PP films was determined by measuring the tensile strength of the copper plated films. The electrical characteristics of the copper plated films in comparison with grafted films were studied. The results showed the high adhesion of the deposited copper film to the grafted PP film as well as the high electrical conductivity. Copyright © 2008 John Wiley & Sons, Ltd. [source] Thin-film silicon solar cell technologyPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2-3 2004A. V. Shah Abstract This paper describes the use, within p,i,n - and n,i,p -type solar cells, of hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon (,c-Si:H) thin films (layers), both deposited at low temperatures (200°C) by plasma-assisted chemical vapour deposition (PECVD), from a mixture of silane and hydrogen. Optical and electrical properties of the i -layers are described. These properties are linked to the microstructure and hence to the i -layer deposition rate, that in turn, affects throughput in production. The importance of contact and reflection layers in achieving low electrical and optical losses is explained, particularly for the superstrate case. Especially the required properties for the transparent conductive oxide (TCO) need to be well balanced in order to provide, at the same time, for high electrical conductivity (preferably by high electron mobility), low optical absorption and surface texture (for low optical losses and pronounced light trapping). Single-junction amorphous and microcrystalline p,i,n -type solar cells, as fabricated so far, are compared in their key parameters (Jsc, FF, Voc) with the [theoretical] limiting values. Tandem and multijunction cells are introduced; the ,c-Si: H/a-Si: H or [micromorph] tandem solar cell concept is explained in detail, and recent results obtained here are listed and commented. Factors governing the mass-production of thin-film silicon modules are determined both by inherent technical reasons, described in detail, and by economic considerations. The cumulative effect of these factors results in distinct efficiency reductions from values of record laboratory cells to statistical averages of production modules. Finally, applications of thin-film silicon PV modules, especially in building-integrated PV (BIPV) are shown. In this context, the energy yields of thin-film silicon modules emerge as a valuable gauge for module performance, and compare very favourably with those of other PV technologies. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||