光致发光
激子
光子上转换
钙钛矿(结构)
纳米晶
材料科学
比克西顿
半导体
卤化物
光电子学
激发
量子点
化学物理
凝聚态物理
纳米技术
发光
化学
物理
结晶学
无机化学
量子力学
作者
Xiaoman Ma,Fang Pan,Haoqi Li,Peng Shen,Chao Ma,Lei Zhang,Haibo Niu,Yun Zhu,Shijie Xu,Honggang Ye
标识
DOI:10.1021/acs.jpclett.9b02289
摘要
The efficient single-photon upconversion photoluminescence (UCPL) feature of lead halide perovskite semiconductors makes it promising for developing laser cooling devices. This is an attractive potential application, but the underlying physics still remains unclear so far. By using the all-inorganic CsPbX3 (X = Br, I) nanocrystal samples, this phenomenon was investigated by photoluminescence (PL) and time-resolved PL under different temperatures and various excitation conditions. A broad emission band located at the low-energy side of the free exciton (FE) peak was detected and deduced to be from the self-trapped exciton (STE). The lifetime of STE emission was found to be 171 ns at 10 K, much longer than that of FE. The UCPL phenomenon was then attributed to thermal activation of transformation from STEs to FEs, and the energy barrier was derived to be 103.7 meV for CsPbBr3 and 45.2 meV for CsPb(Br/I)3, respectively. The transformation also can be seen from the fluorescence decay processes.
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