Accurate Model for Temperature Dependence of Solar Cell Performance According to Phonon Energy Correction

Abstract

In many experiments, it has been reported that the performance of solar cells decreases with increasing temperature. This effect arises due to an increase in the intrinsic carrier concentration of material that directly affects the reverse saturation currents (J0). As a result, the open circuit voltage which is inversely proportional to J0 will decrease quite rapidly with increasing temperature. The intrinsic carrier concentration is determined by the bandgap energy of a material and its temperature. The Varshni relationship is a relation for the variation of the bandgap energy with temperature in semiconductors that has been used extensively in the model of a solar cell performance. But the problem is the Varshni relation just calculates the contribution of the vibrational part at the temperature, which is much greater than the Debye temperature. These works proposed a model of temperature dependence of solar cell performance that involves phonon energy correction and electron-phonon coupling interaction. This correction is applied because the electron-phonon coupling interaction is an intrinsic interaction of semiconductors. The existence of interaction cannot be avoided either experimentally or theoretically. The proposed model is compared with experimental data, which have fairly high accuracy.