Indium amorphous materials

Single crystal silicon (sc-Si), polyciystalline silicon (p-Si), and amorphous silicon (a-Si) can all be used to make solar cells, with fabrication cost and device photoconversion efficiencies decreasing as one moves from single-crystal to amorphous materials. Various properties of these materials are summarized in Table 8.1. Other relatively common solar cell materials include gallium arsenide (GaAs), copper indiirm diselenide (CIS), copper indium-gallium... 

Several periodato complexes of indium(III) have been obtained by using In(N03)3 and HsIOg. At pH < 1, a crystalline product H33l2ln034 forms. At higher pH, insoluble, amorphous material of composition In5(I0g)3 H20 and H3ln4(I06)3 H20 was produced. 

Passive temperature monitors can be used to determine the maximum temperature a substrate has reached in processing. Passive temperature monitors involve color changes, phase changes (e.g. melting of indium), or crystallization of amorphous materials. 

StiU another method used to produce PV cells is provided by thin-fiLm technologies. Thin films ate made by depositing semiconductor materials on a sohd substrate such as glass or metal sheet. Among the wide variety of thin-fiLm materials under development ate amorphous siUcon, polycrystaUine sUicon, copper indium diselenide, and cadmium teUuride. Additionally, development of multijunction thin-film PV cells is being explored. These cells use multiple layers of thin-film sUicon alloys or other semiconductors tailored to respond to specific portions of the light spectmm. 

Various inorganic semiconductors (p-type and/or n-type nonoxide semiconducting materials) sucb as amorphous or crystalline silicon (a-Si or c-Si), gallium arsenide (GaAs), cadmium telluride (CdTe), gallium phosphide (GaP), indium phosphide (InP), copper... 

Although conventional solar cells based on silicon are produced from abundant raw materials, the high-temperature fabrication routes to single-crystal and polycrystalline silicon are energy intensive and expensive. The search for alternative solar cells has therefore focused on thin films composed of amorphous silicon and on other semiconductor heterojunction cells (e.g., cadmium telluride and copper indium... 

Photovoltaics also require significant research activity in the chemical sciences. Low-cost methods are required for producing solar-grade silicon for photovoltaic cells. Better solar cell materials are needed than the presently utilized amorphous silicon. These materials must be more efficient without the use of heavy metals such as cadmium, tellurium, indium, and lead, which present significant environmental issues. An understanding of the degradation process of photovoltaic cells is needed, as is an answer to why these materials lose their effectiveness after prolonged exposure to the sun. Finally, there is a need to develop catalysts for the efficient photochemical conversion of water. 

Abstract Photovoltaic cells have been dominated so far by solid state p-n junction devices made from silicon or gallium arsenide wavers or thin film embodiments based on amorphous silicon, CdTe and copper indium gallium diselenide (CIGS) profiting from the experience and material availability of the semiconductor industry. Recently there has been a surge of interest for devices that are based on nanoscale inorganic or organic semiconductors commonly referred to as bulk junctions due to their interconnected three-dimensional structure. The present chapter describes the state of the art of the academic and industrial development of nanostructured solar cells, with emphasis in the development of the dye-sensitized nanocristalline solar cell. 

Theoretical conversion efficiencies of photovoltaic systems depend on the semiconductor materials used in the cells and on the ambient tanperatuie. The materials currently used to make photovoltaic cells can be grouped into three broad categories 1) expensive, efficient monocrystalline silicon, 2) less efficient but much lower cost polycrystalline silicon, and 3) the lowest cost and poorest performer, amorphous silicon material. Conversion efficiencies of commercial polycrystaUine silicon cells are 10 to 15 percent. Now the primary development areas are in how to use monocrystalline silicon with solar concentrators and making thin-film cells by depositing a 5- to 20-micron film of silicon onto an inexpensive substrate, because the estimated efficiency of these cells is above 20 percent. Work is ongoing with other materials, including amorphous silicon (a-Si), copper indium diselenide (CuInSe2 or CIS) and related materials, and cadmium telluride (CdTe). 

Variety of semiconducting material such as single and poly crystal silicon, amorphous silicon, Cadmium-Telluride (CdTe), Copper Indium/Gal-lium Di Selenide (CIGS) have been employed to form inorganic solar cell based on layers configuration to enhance absorption efficiency, conversion efficiency, production and maintenance cost. 

Semiconductor deposition materials used include amorphous silicon, polycrystalline silicon, micro-crystalline silicon, cadmium telluride, and copper indium selenide/sulfide. Typically, the top surface is low iron solar glass for rigid cells (a fluoropolymer for flexible cells), the encapsulant is crosslinkable ethylene-vinyl acetate (EVA), and the rear layer is a Tedlar - PET - Tedlar laminate (although glass, coated PET, or another bondable polymeric film are also used). 

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