Nonlinear absorption and refraction of Cs₃Cu₂Br₅ perovskite

Halide perovskite (Cs₃Cu₂Br₅) is synthesized by a thermal injection method. The X-ray diffraction (XRD) proves that the Cs₃Cu₂Br₅ crystal phase is an intersection phase. The Cs₃Cu₂Br₅ organic glasses are fabricated by dispersing Cs₃Cu₂Br₅ materials in methyl methacrylate (MMA). The nonlinear absorption (NLA) and the nonlinear refraction (NLR) performances of Cs₃Cu₂Br₅/PMMA organic glasses are measured via the open-aperture (OA) and the closed-aperture (CA) Z-scan technique, respectively. The samples show typical reverse saturable absorption (RSA) and self-focusing effect with the change of input energy (40–72 μJ). Meanwhile, the room-temperature photo-luminescence (PL) measurement reveals light emission for Cs₃Cu₂Br₅. The effects on nonlinear optical (NLO) properties are investigated by controlling the input energy and the amount of the sample. The Cs₃Cu₂Br₅/PMMA organic glasses exhibit excellent NLA and NLR properties. The NLA coefficient of (Cs₃Cu₂Br₅)₁₈/PMMA organic glass is much higher than those of lead-containing perovskite such as CsPbCl₃ and CsPbBr₃ nanosheets. This results in Cs₃Cu₂Br₅/PMMA organic glasses show superior optical limiting (OL) performance. The Cs₃Cu₂Br₅ perovskite materials show great potential in devices such as light-emitting diodes and optical switches.