Simulations of Si based tandem solar cells

Silicon-based tandem cell has recently caught attention as it presents a possible route to boost energy conversion efficiency over 30%. To achieve the goal, choosing companion semiconductors for the top cell with appropriate properties is pivotal. In this paper, we have applied the detailed-balance model to calculate the efficiency of c-Si based tandem cells in terms of the performance of top cells. Our results show that the tandem cell efficiency over 30% is possible for the top cells with the bandgap energy between 1.2 eV and 2.8 eV. For the bandgap energy of 1.2 eV, an open-circuit voltage larger than 0.816 V, or short-circuit current higher than 34.8 mA/cm may be also required to account for the less efficient performance of top cell. Furthermore, the PC1D simulation results provide an intuitive representation of the effects of minority carrier mobility, bulk lifetime and background doping are presented.