Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals

The fundamental properties and ultimate performance limits of organolead trihalide MAPbX(3) (MA = CH3NH3+; X = Br- or I-) perovskites remain obscured by extensive disorder in polycrystalline MAPbX(3) films. We report an antisolvent vapor-assisted crystallization approach that enables us to create sizable crack-free MAPbX(3) single crystals with volumes exceeding 100 cubic millimeters. These large single crystals enabled a detailed characterization of their optical and charge transport characteristics. We observed exceptionally low trap-state densities on the order of 109 to 1010 per cubic centimeter in MAPbX(3) single crystals (comparable to the best photovoltaic-quality silicon) and charge carrier diffusion lengths exceeding 10 micrometers. These results were validated with density functional theory calculations.