The achievement of red upconversion lasing for highly stable perovskite nanocrystal glasses with the assistance of anion modulation

Perovskite materials have received extensive attention as optical gain media.However,it is tough to realize lasing using such materials on account of the unstable structure of MAPbl_(3)/CsPbl_(3)nanocrystals(NCs),and the propensity for mixed-halogen perovskites to undergo phase decomposition into bromine-rich and iodide-rich regions under intense laser irradiation.To solve this issue,we fabricated CsPbX_(3)(X=Br,I)NCs,which were embedded into a glassy matrix with high stability.In addition,by doping Brions into the CsPbl_(3) NCs to partially replace I^(-) ions,the optical efficiency and the optical gain properties were found to be significantly improved.Here,under 800 nm pulse laser excitation,red random lasing was realized with the assistance of such anion modulation.Moreover,we demonstrate that the perovskite NCs glasses(PNG)show strong water stability after immersion in water for one week,seeding a promise for application in high-definition(HD)displays and photonic devices.

Nonlinear optical properties of CsPbCl_(x)Br_(3-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 CsPbCl_(x)Br_(3-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 CsPbCl_(1.5)Br_(1.5)NCs 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^(-5)cm^(3)GW-2)of CsPbCl_(1)Br_(2)NCs glass with high Br anion content are larger than those of CsPbCl_(2)Br_(1)and CsPbCl_(1.5)Br_(1.5)NCs 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.