The temperature dependence of GaInP/GaAs/Ge multi-junction solar cells are numerically modeled. The temperature dependence of the solar cell dark current and the spectral sensitivity of the solar cell are demonstrated. Both aspects of the temperature dependence are connected to the temperature dependence of the semiconductor band gaps. Reduction in the efficiency is simulated by shifting the semiconductor band gaps using the Varshni relation, which in the model creates the corresponding increase in solar cell dark current with increasing temperature. The Varshni relations is further utilized to develop a temperature dependent absorption coefficient model. This model simulates the shift in the external quantum efficiency to longer wavelengths as the temperature increases, which shows good agreement with experimental results. Since standard test conditions of solar cells is at 298 K, this complex numerical model represents an important step forward to studying temperature dependences of multi-junction solar cells under real-world conditions, in which solar cell can operate at temperatures of 50 K above ambient temperatures.
© 2011 Optical Society of AmericaPDF Article