Unveiling the potential of Cs2AgBiBr6 perovskites for next-generation see-through photovoltaics

Lead-free perovskite solar cells are strong contenders in the race for green and sustainable energy. Among these, cesium silver bismuth bromide (Cs2AgBiBr6) stands out, but its potential was hampered by the need for hightemperature processing, hindering its transition to scalable techniques. In this work, we present the feasibility of blade-coating deposition of Cs2AgBiBr6 layer. Thanks to the temperature control of the substrate during the process, we deposited uniform films at precise thickness enabling the fabrication of fully semitransparent devices with power conversion efficiencies (PCEs) of 3.07 % and 7.7 % under 1 sun and indoor light conditions, respectively. Furthermore, we evaluated important metrics for transparent photovoltaics such as Light Utilization Efficiency (LUE) and Color Rendering Index (CRI) of the devices by varying the Cs2AgBiBr6 thicknesses and the illumination conditions. The results showed LUEs at 1 Sun illumination of 1.1 % (1.5 %) and CRI of 71 (62.5) for 200 nm-thick and 400 nm-thick perovskite films, respectively. Finally, we evaluated the process scalability fabricating 6 cm2-sized semitransparent modules suitable for low-power electronics in Internet of Things field. This study opens the door to the development of non-hazardous, scalable, lead-free perovskite solar cells and modules suitable for integration into our everyday surroundings thanks to their see-through properties.