Controllable modulation of morphology and property of CsPbCl₃ perovskite microcrystals by vapor deposition method

As a direct wide bandgap semiconductor, CsPbCl3 has great potential applications in the field of near-ultraviolet photodetectors, lasers and higher-order multiphoton fluorescent detectors. In this work, we synthesized CsPbCl3 micro/nanocrystals by vapor deposition method with CsCl and PbCl2 powders as the source materials. It was confirmed that the formation of CsPbCl3 perovskite through the chemical reaction of CsCl with PbCl2 occurred in the quartz boat before the source evaporation, not in vapor or on substrate surface. The evaporated CsPbCl3 can form micro/nanocrystals on substrate surfaces under appropriate conditions. Various morphologies including irregular polyhedrons, rods and pyramids could be observed at lower temperature, while stable and uniform CsPbCl3 single crystal microplatelets were controllably synthesized at 450 degrees C. Prolonging the growth time could modulate the size and density of the microcrystals, but could not change the morphology. Substrate types made little difference to the morphology of CsPbCl3 crystals. The photoluminescence spectra indicated that the crystallinity and morphology of CsPbCl3 micro/nanocrystals have significant effects on their optical properties. The work is expected to be helpful to the development of optoelectronic devices based on individual CsPbCl3 microcrystal.