The effect of band gap of semiconductor on the efficiency of photovoltaic solar cells

Abstract

Photovoltaic technologies, with an essentially infinite energy source, large total capacity, and demonstrated cost competitiveness, are well-positioned to meet growing global demand for clean energy. The photovoltaic is advantageous primarily for its direct optical band gap which is well matched to the standard AM 1.5G solar spectrum, and its high absorption coefficient. Major advances in device performance have been achieved through improved current collection and fill factor, however, the open-circuit voltage (VOC) of devices remains limited compared to the band gap-determined maximum achievable VOC. The voltage deficit could be minimized through various approaches, and this work addresses it through progressive structural changes to a device. Absorbers of less than 2 µm were pursued for ultimate electron-reflector devices which incorporate a wide band-gap material behind the absorber to induce a back-surface field via a back-side conduction-band offset for improved VOC. An optimized and stable base structure is necessary to quantify characteristics and improvements in progressive devices with additional material layers. In this study the temperature, band gap and efficiency are studied, how they affect the performance of the solar cell. The Shockley–Queisser equation puts a theoretical limit on the efficiency of single-junction mono- silicon (Si), Germanium (Ge), gallium arsenide (GaAs) and Cadmium Telluride (CdTe) of solar cells (meaning, a definite single value for the band gap energy). Variation in temperature inversely affects the efficiency. With increase in Band Gap efficiency also increase till band gap reaches; moreover, increase in band gap increases efficiency and also open circuit voltage value gets larger .