| Organolead halide CH3NH3PbX3(MAPbX3, X=C1, Br, I) perovskites are emerging as attractive materials for photovoltaic devices and other photovoltaics due to their excellent optoelectronic properties including long carrier lifetime, high absorption coefficient, high charge mobility(or diffusion coefficient). Organolead halide perovskite nanowire and nanoplate single-crystals have been reported as an ideal candidate in nanophotonics and nanoscale poetoelectronics owing to their remarkable photophysical performance.Herein, we synthesize the MAPbX3 (X=Br, I) single-crystals through solution-based synthesis, and confirm that the single-crystals are high-quality. We report the direct visualization and quantitative of diffusion progress in single-crystal NWs and NPs using home-built photoluminescence (PL)-scanned imaging microscopy coupled with a time-corrected single photon counting (TCSPC). This method should be also applicable to other optoelectronic materials. On the other hand, through mapping the local photoluminescence (PL) dynamics using laser/PL-scanned confocal imaging microscopy and simulating the carrier diffusion process in an individual MAPbI3 single-crystalline particle, we report that the rapid diffusion of charge carriers can produce a fast local PL kinetics when the perovskite is partially excited. This result indicates that using PL kinetics to estimate the carrier lifetime in perovskite single crystals needs to exclude the effect of carrier diffusion.We compare the effect of different Cl source from PbCl2 and MACl to the synthesis of the MAPbBr3 single-crystal and find that Cl in MAC1 participates in crystal formation. However, when the content of PbCl2 is small, Cl ion does not involve in crystal formation until the PbCl2 content reaches to a certain value. With the increase of the PbCl2 content, the carrier lifetime increases at first and decreases afterwards, while diffusion coefficient is not related to the carrier lifetime. |
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