Enhancement in Open-Circuit Voltage of Semitransparent MAPbI3-xBrx perovskite solar cells by methyl amine treatment and optimal Hole Transport Layer

Wide bandgap perovskites (>1.7 eV) find applications in multi-junction solar cells and semi-transparent absorbers for building integrated photo-voltaics. Here we present the improvement in morphology and power conversion efficiency (PCE) of two mixed halide perovskite compositions: MAPbIBr ₂ and MAPbBr ₃ by methyl amine (MA) vapor treatment. MA treatment improves the morphology and surface coverage leading to increase in open-circuit voltage (V _oc ) and short-circuit current (J _sc ). Further two polymers are used as hole-transporting materials which have better HOMO matching with perovskite than Spiro-OMeTAD and results in V _oc of 1.12 V and 1.17 V for MAPbIBr ₂ and MAPbBr ₃ respectively compared to 0.95 V and 1.10 V of the corresponding devices with Spiro-OMeTAD as HTL.