CsPbIBr2‐Based Bifacial Semitransparent Solar Cells for All‐Day Applications

Among all‐inorganic perovskites, CsPbIBr 2 has become a potential candidate in semitransparent perovskite solar cells (ST‐PSCs) due to its excellent thermal stability and suitable bandgap. Herein, by optimizing the ambient temperature in an N 2 ‐filled glovebox, the growth process of CsPbIBr 2 crystals is regulated to avoid the generation of pinholes and improve the photoelectric conversion capacity of perovskite cells. When the ambient temperature is around 25 °C, the champion power conversion efficiency (PCE) of 10.82% with opaque n–i–p structure is achieved. Based on MoO x /Ag/MoO x (20/12/20 nm) multilayer top electrode, the ST‐PSC device achieves a maximum PCE of 7.06% at the fluorine‐doped tin oxide side under the simulated 1 sun illumination condition and a PCE of 23.96% at MoO x /Ag/MoO x electrode side under the intensity of 1000 lux (≈350 μW cm −2 ) provided by a white light‐emitting diode lamp, along with an average visible transmittance of 29.25%. The resulting perovskite solar cell is the first bifacial inorganic ST‐PSC that could be used under both sunlight and indoor light, which is an important step toward all‐day power generation of inorganic ST‐PSCs and building‐integrated photovoltaics.