“…, with a formula A x Cu y X z (A = Cs + , Rb + , CH 3 NH 2 + , or CH 4 N 2 + ; X = Cl – , Br – , or I – ). − Among them, much attention has been given to Cu + -based halides, which have been demonstrated as good luminescent materials. For Cu 2+ , very recently, Cs 2 CuBr 4 halide was reported as a photocatalyst for the photocatalytic CO 2 reduction reaction . Meanwhile, for CsCuCl 3 with a one-dimensional (1D) chain hexagonal perovskite structure, its narrow bandgap and high thermal stability may render it as a kind of good photoelectric material. , However, there were only a few reports concerning its photoelectric properties and applications, such as photoelectrical detectors and fluorescence sensors for detecting transition metal ions (Fe 2+ , Cr 2+ , Mn 2+ , Pb 2+ , etc .…”