Phase control in the synthesis of cesium copper iodide compounds for their photoluminescence and radioluminescence study

Lead-free metal halide perovskites have attracted much attention owing to their non-toxicity and excellent optical properties . Especially, cesium copper iodide compounds exhibit advantages of good environmental stability and low cost, rendering promising potential applications in optoelectronic devices field. Here, we use an anti-solvent assisted crystallization method to realize phase control syntheses of CsCu 2 I 3 and Cs 3 Cu 2 I 5 by varying the concentrations of precursor solution. Using high precursor solution concentrations, Cs 3 Cu 2 I 5 with strong blue emission peak at 440 nm is prepared. While the CsCu 2 I 3 is fabricated at low precursor solution concentrations, with the yellow emission peak of 580 nm. Furthermore, the UV-pumped light-emitting diodes (UV-LEDs) are realized by adopting CsCu 2 I 3 and Cs 3 Cu 2 I 5 powders as phosphors, and we also obverse the scintillation characteristic of the cesium copper iodide powders, showing potential applications for lighting and X-ray detection devices.