The Role of Surface Defects in Photoluminescence and Decay Dynamics of High-Quality Perovskite MAPbI3 Single Crystals.

Halide perovskites have recently been a star semiconductor material in photovoltaic field owing to their excellent optoelectronic properties. An in-depth understanding of the photoluminescence and carrier diffusion in these materials may facilitate the implementation of high-performance optolelctronic devices. Here, we report an unusual photoluminescence quenching phenomenon in MAPbI3 single crystals. Interestingly, MAPbI3 single crystal with higher crystalline quality shows a lower photoluminescence emission and a shorter decay time, indicating the surface imperfection plays an important role to the photoluminescence. The quick quenching process is attributed to the synergistic effect of localized effect at the defects and rapid inward diffusion.