Characterization of quenching defects in methylammonium lead triiodide (CH3NH3PbI3)

Organometal halide perovskites have attracted broad interest over the last several years for their promising applications in solar cells and light-emitting devices. It is believed that crystal defects play important roles in the photophysical processes. However, the detailed mechanism is still unclear. In this work, by using luminescence microscopy, we characterized the quenching defects correlating with crystal size, location and morphology. It is clear that needle-shaped crystals own better crystal quality with less defects; and more defects are located in the center of the crystals comparing to the edge. Relatively higher concentration of PbI2 precursor will generate more defects during the preparation. Characterization of defects is the first step to understand the quenching mechanism and to fully understand the photophysical properties of organometal halide perovskite.