Simultaneous Interfacial Modification and Defect Passivation for Wide‐Bandgap Semitransparent Perovskite Solar Cells with 14.4% Power Conversion Efficiency and 38% Average Visible Transmittance

Perovskite materials offer a great potential in the application of semitransparent solar cells, owing to the tunable bandgap, ease of preparation and excellent photovoltaic property. A majority of works exhibit high average visible‐light transmittance (AVT) for semitransparent perovskite solar cells (ST‐PSCs) through decreasing perovskite thickness, leading to sacrificing the power conversion efficiency (PCE) of the device. Herein, a wide‐bandgap (WBG) perovskite of Cs0.2FA0.8Pb(I0.6Br0.4)3 is applied as absorber in ST‐PSCs, which is a tremendous progress to balance both large PCE and high AVT. Moreover, a strategy of simultaneous interfacial modification and defect passivation is provided to enhance the performance of WBG ST‐PSCs. Consequently, an inverted planar structure WBG perovskite solar cell (PSC) achieves 15.06% of PCE with excellent stability by restraining the interfacial energy loss and suppressing the nonradiative recombination. Furthermore, the ST‐PSC obtains high PCE of 14.40% with an AVT of 38% by means of optimizing the transparent electrode. This work provides an efficient and simple method to improve the performance and AVT of ST‐PSCs for the application in building‐integrated photovoltaics. The wide‐bandgap perovskite (WBG) of Cs0.2FA0.8Pb(I0.6Br0.4)3 (FA: HC(NH2)2) is employed for semitransparent perovskite solar cells (ST‐PSCs). By simultaneous interfacial modification and defect passivation to suppress energy loss and nonradiative recombination, a high efficiency of 15.06% is achieved for WBG‐PSCs with excellent stability. Consequently, the ST‐PSCs realize 14.4% of efficiency with high average visible transmittance of 38% through optimizing the semitransparent electrode.