Growth and performance of CsCu(Br, Cl)3 single crystals

This paper presents the growth of large-sized CsCu(Br, Cl)3 crystals using the aqueous solution evaporation method. The structure and the components of the crystals were analyzed. It was found that CsCuBr3 is a direct bandgap material, while CsCuCl3 is an indirect bandgap material, and the band gap of CsCu(Br, Cl)3 halides can be adjusted in the range of 2.63–3.63 eV (PBE) by changing the ratio of Br-/Cl-. Besides CsCuCl3, which has an absorption valley at 654 nm, the other CsCu(Br, Cl)3 crystals show high absorption in the range of 200–1000 nm. Under UV excitation, the PL spectra show that CsCu(Br, Cl)3 crystals exhibit red and blue emission.