Perovskite/Silicon Tandem Solar Cells With Efficiency Over 33% Achieved by Additive Engineering

As top cells in perovskite/silicon tandem solar cells (TSCs), the wide-bandgap (WBG) perovskite solar cells (PSCs) suffer from significant open-circuit voltage (Voc) loss, which greatly limits the efficiency improvement. Trap-assisted non-radiative recombination has been recognized as the major cause for the voltage loss. Additive engineering has been proven an efficient strategy to passivate defects and suppress non-radiative recombination. In this work, we introduce a novel sulfonate additive into WBG $(\text{Eg}=1.68\text{eV})$ perovskite precursor. With this sulfonate additive incorporation, the trap density is reduced, and carrier lifetime is significantly improved. When combining the optimized WBG PSC with silicon heterojunction bottom cell in a tandem device, we obtain a high $V_{\text{OC}}$ of 1.966 V. Furthermore, the two-terminal perovskite/silicon TSCs of 1 $\text{cm}^{2}$ demonstrate a high efficiency of 33.34%. Our findings provide a feasible approach to prepare highly efficient perovskite/silicon TSCs.