Abstract
High band gap semi-transparent solar cells based on CH3NH3PbBr3 perovskite are attractive for building integration, tandem cells and electrochemical applications. The lack of control of the CH3NH3PbBr3 perovskite growth limit the exploitation of CH3NH3PbBr3-based perovskite solar cells. In this paper, we introduce a post-treatment performed after the initial CH3NH3PbBr3 crystallization based on methylamine gas that drastically enhances the perovskite quality leading to a highly cristalline film with improved average visible transmittance (AVT) close to 56%. Opaque devices showed outstanding results in terms of open-circuit voltage and power conversion efficiency (PCE) reaching 1.54 V and 9.2%, respectively. These achievements are ascribed to a film with reduced morphological defects and better interface quality and reduced non-radiative pathways. For the first time, the fabrication of semi-transparent CH3NH3PbBr3-based solar cells is demonstrated reaching a maximum PCE equal to 7.6%, an AVT of the full stack device of 52% and an excellent light stability at maximum-power point tracking.