Nonlinear optical properties of CsPbClxBr3-x nanocrystals embedded glass

All-inorganic perovskite has attracted significant attention due to its excellent nonlinear optical characteristics.Stable and low-toxic perovskite materials have great application prospects in optoelectronic devices. Here, we study the nonlinear optical properties of CsPbClxBr3-x(x=1,1.5, 2) nanocrystals(NCs) glass by open-aperture Z-scan. It is found that the two-(2 PA) and three-photon absorption(3 PA) intensity can be adjusted by the treatment temperature and the ratio of halide anions. The perovskite NCs glass treated at a high temperature has better crystallinity, resulting in stronger nonlinear absorption performance. In addition, the value of the 2 PA parameter of CsPbCl1.5Br1.5NCs glasses decreases when the incident pump intensity increases, which is ascribed to the saturation of 2 PA and population inversion. Finally, the research results show that the 2 PA coefficient(0.127 cm GW-1) and 3 PA coefficient(1.21×10-5cm~3 GW-2) of CsPbCl1Br2NCs glass with high Br anion content are larger than those of CsPbCl2Br1and CsPbCl1.5Br1.5NCs glasses. This is mainly due to the greater influence of Br anions on the symmetry of the perovskite structure, which leads to the redistribution of delocalized electrons. The revealed adjustable nonlinear optical properties of perovskite NCs glass are essential for developing stable and high-performance nonlinear optical devices.