Nonconventional (Non-Silicon-Based) Photovoltaic Materials

Although photovoltaic devices and modules made from crystalline silicon currently dominate the market, many efforts in developing photovoltaics involve the use of alternative materials. Binary and multinary materials with direct band gaps and therefore high absorption coefficients allow for the fabrication of thin-film photovoltaic modules with minimized material use and the possibility for depositing on large areas and alternative substrates such as glass, stainless steel, or polyimide foils. With the great diversity of optoelectronic properties of binary and multinary materials, highly efficient photovoltaic devices fabricated at very low cost are in principle possible. Requirements for efficient photovoltaic devices using nonconventional materials are discussed, and results obtained for photovoltaic devices based on selected binary and multinary materials obtained during the past few decades are summarized.