Effects of methylamine doping on the stability of triple cation (FA0.95-xMAxCs0.05)PbI3 single crystal perovskite

Abstract: As a promising photovoltaic device, organic-inorganic halide perovskite materials’ widespread use is still hindered by its undesirable stability. To cope with this challenge, methylamine (MA) is doped into triple cation perovskite single crystals as (FA0.95-xMAxCs0.05)PbI3, five different MA molar ratios (x=0, 0.05, 0.10, 0.15, 0.20) cesium-containing triple cation perovskite single crystals are synthetized and characterized. Among them, (FA0.8MA0.15Cs0.05)PbI3 shows high stability against water-oxygen and light within 60 days, and the thermal decomposition temperature of (FA0.8MA0.15Cs0.05)PbI3 reaches as high as 305 °C. Besides, the carrier lifetime of (FA0.8MA0.15Cs0.05)PbI3 is up to 5.957 us, which maintains 95% after 60 days of light illumination as 5.646 us. The work studies the stability of perovskite single crystals based on (FA0.95-xMAxCs0.05)PbI3 compositions and provides a reference for the discovery of novel perovskite photovoltaic devices with high efficiency and long-term stability.