标题：Tunable fluorescence and optical nonlinearities of all inorganic colloidal cesium lead halide perovskite nanocrystals

Abstact：The formation of cesium lead halide perovskite nanocrystals are very effortless due to its extremely fast reaction kinetics. Herein, we present simple hot-inject approach and anion exchange reaction to fabricate all inorganic colloidal CsPbX3 perovskite nanocrystals (NCs). The colloidal CsPbX3 NCs with controllingsize exhibit the characteristics of the high luminescent intensity, superior quantum yields (QY, above 69%) and the narrow-band emission tuning, the bandgap energies and emission spectra are readily tunable over the entire visible spectral region of 425e710 nm. Moreover, the third-order nonlinear optical properties of all inorganic colloidal perovskite nanocrystals (CsPbCl3, CsPbBr3, CsPbI3) were measured using the Z-scan technique, indicating excellent third-order optical nonlinearities. Nonlinear optical susceptibilities reaching to 3.78  10 11 esu for CsPbBr3 NCs, figure of merit is achieving above 5 for CsPbI3 NCs. These interesting results demonstrate that the as-prepared all inorganic colloidal CsPbX3 perovskite nanocrystals are expected to hold great promise for application on nonlinear optoelectronic devices.

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