Solar cell material

Lee, J.-K. Yang, M., Progress in light harvesting and charge injection of dye-sensitized solar cells. Materials Science Eng., B Adv. Funct. Solid-State Mat. 2011,176 1142-1160. 

It is also used as an alloy to make electrical contacts harder and wear longer, for medical instruments, and more recendy as an experimental metal for direct conversion of solar cell material to electrical energy. 

On earth, as opposed to outer space, the most common solar cell material is silicon. An atom of silicon has 14 electrons, arranged in three different shells, ls 2s 2p 3s 3p. The first two shells are full, while the outer shell is half full, hence there are four electrons a silicon atom can and does share with its neighboring atoms. Pure silicon is a poor conductor of electricity since none of its electrons are free to move about. 

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... 

While silicon is not the ideal solar cell material, it currently dominates the solar PV market due to its prevalence in the microelectronics industry. Crystalline silicon (c-Si) is an inorganic semiconductor, in which the valence-band maximum and conduction-band minimum are not directly aligned in Uspace, making c-Si an indirect bandgap material. The indirect nature of the bandgap in c-Si means that a considerable change in momentum is required for the promotion of an electron from... 

Heremans P, Cheyns D, Rand BP (2009) Strategies for increasing the efficiency of heterojunction organic solar cells material selection and device architecture. Acc Chem Res 42 1740... 

Inorganic monomers can be used to plasma-deposit polymer-type films (16). At high plasma energies, the monomers are largely decomposed and can be used to form materials such as amorphous hydrogen-containing silicon films from SiH4 for thin-film solar-cell materials. 

This entry gives a brief historical overview and discussion of relevant material properties, followed by a survey of the methods currently used to produce solar cell materials, with an emphasis on silicon. 

Pivrikas A., Juska G., Mozer A. J., Scharber M., Arlauskas K., Sariciftci N. S., Stubb H. and Osterbacka R. (2005), Bimolecular recombination coefficient as a sensitive testing parameter for low-mobility solar-cell materials , Phys. Rev. Lett. 94, 176506-1-176506-4. 

Figure 7 Thermal-wave image of Si solar cell material showing grain structure.

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. 

R. Brendel, Crystalline thin-film silicon solar cells from layer-transfer processes are-view, Proc. 10th Workshop on Crystalline Silicon Solar Cell Materials and Processes, 117-125 (2000). 

This, in principle, describes the essentials of a solar cell. The following portions of the article deal with each part of the solar cell in more detail, present a quantitative description of its performance, indicate performance limitations (called the efficiency of the solar cell), and give a variety of solar cell materials with comparative performance. 

Thin Film Cells. Future, lower cost solar cell materials will likely be more flexible than crystalline silicon and therefore may not require a rigid member In the module lay up. They will still need electrical Isolation and protection fradhesive layers as well as outer covers/insulators. 

Characterization of Solar Cell Materials using Electrolyte Contacts... 

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