Semi-transparent triple cation Perovskite solar module exceeding 8% efficiency for BIPV applications

The Building Integration Photovoltaics (BIPV) makes possible the power generation from roofs, windows or facades. The c-Si or a-Si PV cannot fully satisfy aesthetic requirements as transparency and colouring, and facing problems as poor irradiation, shading and temperatures. Among the new generation PV, Perovskite solar cell technology reached top efficiencies in a few years together with a low-cost perspective. Different strategies related to the Perovskite layer (thickness, morphology, mesh-structure, band-gap tuning) and to alternative top-electrodes can be implemented to achieve the semi-transparent feature for BIPV applications. Here the stable triple cation CsMAFA Perovskite is used for the first time in literature to realize a semi-transparent module (about 90% geometrical fill factor) with a highly transparent sputtered ITO top-electrode. The optical and electrical characterizations of the device show an average visible transmittance (AVT) equal to 10% on the module full stack and area, and an efficiency more than 8%. A failure analysis by Dark Lock-In Thermography (DLIT) and Electroluminescence (EL) imaging indicates the route to optimize the PV device. Finally, this work provides a simple method to realize the semi-transparent CsMAFA Perovskite solar module for BIPV.