Effects of guanidinium addition to CH3NH3PbI3−xClx perovskite photovoltaic devices

CH 3 NH 3 PbI 3¹x Cl x -based photovoltaic devices with guanidinium [C(NH 2 ) 3 , GA] were fabricated and characterized.The additive effects of guanidinium iodide, formamidinium [CH(NH 2 ) 2 , FA] iodide, and guanidinium chloride were compared.Short-circuit current densities, open-circuit voltages, series resistances and shunt resistances were improved by the GA addition.The short-circuit current densities were increased by FA addition with GA.The incident photon-to-current conversion efficiency increased, which results from the suppression of pin-holes in perovskite layers by GA addition.The conversion efficiencies were improved by GA addition.X-ray diffraction showed that the lattice constants of the perovskite crystals increased by GA and FA addition, and that the GA substituted partially at the CH 3 NH 3 -site.