Chapter 3 - Introduction of inorganic solar cells

Abstract

Solar cells can be either classified by generation or materials used as the main sunlight absorbing material. The first working solar cell was silicon wafer-based and used all-inorganic materials in its whole structure. However, overtime, other solar cell absorbers, including binary, ternary, or even quaternary compounds, demonstrated semiconducting properties for use as a p-n junction type of device structure. The inorganic semiconductor materials used in the most conventional p-n structured photovoltaic cells are comprised of crystalline, multicrystalline, amorphous, and microcrystalline silicon (Si), III–V compounds and alloys such as gallium arsenide, chalcogenides such as cadmium-telluride (CdTe), chalcopyrite compounds, such as copper-indium-gallium-diselenide, copper-zinc-tin-sulfide, etc. As a whole, inorganic solar cells exhibit the most stable performance with longer life-span, which has helped to provide faster commercialization. However, most researchers are still trying to reduce the thickness of the films from bulk to thin films, which can be deposited on top of supports like glass, metal foil, or polymer substrates. Thin films provide folks that can be advantageous, but these approaches mainly target material reduction and various functionality-related loss mechanisms in thicker bulk form. Today’s commercialized inorganic thin film solar cells are mainly a-Si-, CdTe-, or CIS-based with approximately 10% market share.