Mechanochemical Synthesis and Characterisation of Luminescent Caesium Copper Iodide Perovskites

The use of high-temperature and hazardous solvents in the synthesis of caesium copper iodides, which are lead-free and exhibit promise for optoelectronic applications, has led to efforts in developing a solvent-free mechanochemical approach. This approach aims to achieve a highly luminescent synthesis of caesium copper iodides powder that can be easily scaled up. In this study, the introduction of Br doping is investigated, and its effects on the optoelectronic properties are examined. Similar observations are made for a 1D variant of the caesium copper iodides. Structural details of the synthesized powder are analysed using Rietveld refinement analysis of the X-ray diffraction patterns. Changing dimensionality from 1D to 0D demonstrates a larger Stokes shift, sharper full-width-half-maximum (FWHM), and faster time-resolved photoluminescence (TRPL) decay time, while more Br dopant results in larger Stokes shift, sharper FWHM, and slower TRPL decay time. The findings of this study suggest that the mechanochemical approach can serve as an
alternative and potential method for fabricating high-quality lead-free metal halides.