Temperature and Intensity Dependence of the Limiting Efficiency of Silicon Solar Cells

Abstract

The temperature and intensity dependence of the limiting efficiencies of monofacial and bifacial silicon solar cells are calculated from the physical properties of silicon assuming light trapping by Lambertian scattering from rough surfaces. The maximum efficiency of a bifacial cell (28.92%) is lower than the efficiency of a monofacial cell (29.46%) at room temperature and Air Mass 1.5 Global illumination. The effects of electron-electron interactions on the band gap, radiative recombination rate, and optical absorption are included self-consistently. The temperature coefficient of the output power is -0.23%/°C for the optimum thickness monofacial cell at room temperature. The optimum thickness of silicon solar cells decreases strongly with temperature following a power law T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> and thin cells have a lower temperature coefficient than thick cells. A surface recombination velocity of 1 cm/s is found to be a turning point below which surface recombination has a small effect on the efficiency.