Abstract
Due to excellent performance and low fabrication costs, perovskite solar cells have become an attractive choice for building integrated photovoltaics (BIPV), especially semitransparent windows. Semitransparent perovskite solar cells are also useful as the upper sub-cell in tandem applications. In this study, we demonstrate efficient perovskite solar cells with good transparency in the visible spectrum (400–800 nm). The device efficiency and transparency were controlled by varying the perovskite layer thickness, including devices with a perovskite thickness as low as 40 nm. A dielectric/metal/dielectric (D/M/D) electrode was used as the transparent back electrode. The best performing device exhibited >9% efficiency at 12.4% average visible transparency. By reducing the perovskite layer thickness, the transparency further increased to 20.5% at an efficiency of 3.5%. Furthermore, perovskite layer thickness-dependent hysteresis behaviour, colour perception in human eye and month-long systematic degradation patterns are investigated and discussed comprehensively. The resulting solar cells are one of the highest performing semitransparent perovskite solar cells using D/M/D back electrode and a significant step forward to BIPV and tandem applications.