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

The fundamental properties and ultimate performance limits of organolead trihalide MAPbX₃ (MA = CH₃NH₃⁺; X = Br^- or I^-) perovskites remain obscured by extensive disorder in polycrystalline MAPbX₃ films. We report an antisolvent vapor-assisted crystallization approach that enables us to create sizable crack-free MAPbX₃ 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 MAPbX₃ 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.