Strain Modulation for Light‐Stable n–i–p Perovskite/Silicon Tandem Solar Cells

Abstract Perovskite/silicon tandem solar cells are promising to penetrate photovoltaic market. However, the wide‐bandgap perovskite absorbers used in top‐cell often suffer severe phase segregation under illumination, which restricts the operation lifetime of tandem solar cells. Here, a strain modulation strategy to fabricate light‐stable perovskite/silicon tandem solar cells is reported. By employing adenosine triphosphate, the residual tensile strain in the wide‐bandgap perovskite absorber is successfully converted to compressive strain, which mitigates light‐induced ion migration and phase segregation. Based on the wide‐bandgap perovskite with compressive strain, single‐junction solar cells with the n–i–p layout yield a power conversion efficiency (PCE) of 20.53% with the smallest voltage deficits of 440 mV. These cells also maintain 83.60% of initial PCE after 2500 h operation at the maximum power point. Finally, these top cells are integrated with silicon bottom cells in a monolithic tandem device, which achieves a PCE of 26.95% and improved light stability at open‐circuit.