Use of hetero intrinsic layer in GaAs P-I-N solar cell to improve the intermediate band performance

Intermediate band solar cell (IBSC) uses the below bandgap photons to minimise the spectral losses and to overcome the thermodynamical efficiency barrier for single junction solar cell set by Shockley and Queisser. With several practical constraints the IBSC is incapable to reach that thermodynamic barrier. Among them, increased recombination (both radiative and non-radiative) is a notable one, which significantly deteriorates the open-circuit voltage. In this paper a single junction GaAs PIN solar cell is proposed, where an InGaAs/GaAs hetero i-layer is introduced to the i-region. Inclusion of this i-layer reduces the transmission losses effectively by introducing an energy shift. This energy shift decouples the valence band form the intermediate band (IB), resulting an improvement in the carrier life time of electron hole pairs in the IB. As a result, the conversion efficiency increases significantly as compared to IBSC.