Nonlinear Absorption and Low-Threshold Multiphoton Pumped Stimulated Emission from All-Inorganic Perovskite Nanocrystals

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• 作者：Yue Wang ; Xiaoming Li ; Xin Zhao ; Lian Xiao ; Haibo Zeng ; Handong Sun
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：448-453
• 全文大小：416K
• ISSN：1530-6992

文摘

Halide perovskite materials have attracted intense research interest due to the striking performance in photoharvesting photovoltaics as well as photoemitting applications. Very recently, the emerging CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals have been demonstrated to be efficient emitters with photoluminescence quantum yield as high as ～90%, room temperature single photon sources, and favorable lasing materials. Herein, the nonlinear optical properties, in particular, the multiphoton absorption and resultant photoluminescence of the CsPbBr₃ nanocrystals, were investigated. Notably, a large two-photon absorption cross-section of up to ～1.2 × 10⁵ GM is determined for 9 nm sized CsPbBr₃ nanocrystals. Moreover, low-threshold frequency-upconverted stimulated emission by two-photon absorption was observed from the thin film of close-packed CsPbBr₃ nanocrystals. The stimulated emission is found to be photostable and wavelength-tunable. We further realize the three-photon pumped stimulated emission in green spectra range from colloidal nanocrystals for the first time. Our results reveal the strong nonlinear absorption in the emerging CsPbX₃ perovskite nanocrystals and suggest these nanocrystals as attractive multiphoton pumped optical gain media, which would offer new opportunities in nonlinear photonics and revive the nonlinear optical devices.