A Simple Deposition Method for Self-Assembling Single Crystalline Hybrid Perovskite Nanostructures

A sequential deposition method is developed, where the hybrid organic–inorganic halide perovskite (CH_3NH_3Pb (I_1-xBr_x)_3) is synthesized using precursor solutions containing CH_3NH_3I and PbBr_2 with different mole ratios and reaction times. The perovskite achieved here is quite stable in the atmosphere for a relatively long time without noticeable degradation, and the perovskite nanowires are proved to be single crystalline structure, based on transmission electron microscopy. Furthermore, strong red photoluminescence from perovskite is observed in the wavelength range from 746 nm to 770 nm with the increase of the reaction time, on account of the exchanges between I^- ions and Br^- ions in the perovskite crystal. Lastly, the influences of concentration and reaction time of the precursor solutions are discussed, which are important for evolution of hybrid perovskite from nanocuboid to nanowire and nanosheet.