Lead-free zero-dimensional Cs2ZnBr4 perovskite single crystals with broadband emission covering visible spectrum

All-inorganic lead-free zero-dimensional (0D) metal halides perovskites with intriguing photoluminescent (PL) properties have aroused much interest due to their application in lighting and artificial illumination. Herein, 0D Cs2ZnBr4 perovskite single crystals were synthesized through simple solvothermal method. The phase purity, the electronic band structure and electronic density of states of Cs2ZnBr4 are investigated by X-ray diffraction (XRD) measurement and density functional theory (DFT) calculation. Under 430 nm blue light excitation, Cs2ZnBr4 single crystals exhibit broadband emission covering the visible region from 450 to 750 nm and large Stokes shift about 120 nm, originating from self-trapped excitons (STEs) radiative recombination. And Cs2ZnBr4 shows excellent thermal and air stability. These results indicate the potential application of Cs2ZnBr4 as environmental-friendly light emitters for solid state lighting and displaying.