Developments of Solar Cell Materials and Fabrication Technology and their Effects on Energy Conversion Efficiency

This paper reviews the present status and future developments of solar cell materials for photovoltaic (PV) application. The solar cell made from different materials, such as silicon with different structures, cadmium telluride (CdTe), gallium arsenide GaAs), copper indium gallium diselenide (CIGS) and polymers are compared in theoretical ability, energy conversion efficiency, production and maintenance costs as well as environmental effects. Several important strategies to improve energy efficiency, such as anti-reflective coating (ARC), multi-junction concentrator and black silicon technique that improve the light-trapping and absorption properties of solar cells, are discussed. The review results show that the most efficient solar cells achieved 50% energy conversion, whereas silicon-based PV cells can reach 27%. Today the market is dominated by crystalline silicon in multi-crystalline and mono-crystalline forms due to it being the second most abundant element on the earths crust, and its nontoxic and environmental-friendly nature compared with other materials. Development of a new process with low cost, high efficiency and environment-friendly nature to produce solar grade silicon is of significant importance for the PV industry.