The effect of double doped nc-Si:H tunnel recombination junction in a-Si:H/c-Si tandem solar cells

In this study, tunneling mechanisms controlling the a-Si:H thin film/c-Si tandem solar cell were investigated employing numerical simulation. First, the effect of doped nc-Si:H tunnel recombination junction (TRJ) was studied with different structures. The band diagram, electric field, and recombination rate characteristics were investigated under a dark condition with doped nc-Si:H TRJ. The trap-assisted model and field-dependent tunneling were used to model the recombination and transport influence of the valence band offset (ΔEV) between the p-type layer of the top cell and TRJ in the high field region. Simulation results showed that the highest efficiency of 23.98% (Short circuit current density, Jsc = 18.74 mA cm−2, open circuit voltage, Voc = 1.565 V, fill factor, FF = 81.76%) could be obtained in the case of n/p nc-Si:H TRJ.