Facile synthesis and characterization of CsPbBr3 and CsPb2Br5 powders

摘要

All-inorganic caesium lead-halide perovskite CsPbBr3 and CsPb2Br5 powders have emerged as attractive optoelectronic materials owing to their stabilities and highly efficient photoluminescence (PL). Herein we report a facile chemical route to prepare highly luminescent monoclinic CsPbBr3 and tetragonal CsPb2Br5 powders at room temperature. The CsPbBr3 powders exhibit regular crystal shape and demonstrate polyhedral geometry with an average particle size of 10 mu m. The CsPb2Br5 powders show platelet morphologies and the lateral sizes of the particles are from 5 up to 200 mu m. Both CsPbBr3 and CsPb2Br5 powders present a narrow emission line-width and PL emission of 528 and 527nm, respectively. A direct hand gap of 2.35 eV and an indirect hand gap of 3.01 eV are calculated for CsPbBr3 and CsPb2Br5 powders, respectively. In addition, the monoclinic CsPbBr3 can be transformed to tetragonal CsPb2Br5 in the presence of water. The large-scale synthesis of CsPbBr3 and CsPb2Br5 will be advantageous in future applications of optoelectronic devices.