Temperature-Dependent Photoluminescence of CdSe-Core CdS/CdZnS/ZnS-Multishell Quantum Dots
Temperature-Dependent Photoluminescence of CdSe-Core CdS/CdZnS/ZnS-Multishell Quantum Dots
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CdSe-核 CdS/CdZnS/ZnS-多壳量子点的温度依赖性光致发光
DOI：
10.1021/jp902080p
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发表时间：
2009-08-06
影响因子：
3.7
通讯作者：
Masumoto, Yasuaki
中科院分区：
文献类型：
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作者：
Jing, Pengtao;Zheng, Jinju;Masumoto, Yasuaki
研究了 CdSe 核 CdS/CdZnS/ZnS 多壳量子点 (QD) 的光致发光 (PL) 光谱，以了解 80 至 360 K 温度范围内的辐射和非辐射弛豫过程。发现 CdSe 量子点中随壳结构变化而发生的温度依赖性非辐射弛豫过程的机制是从 CdSe 核 QD 中表面缺陷/陷阱对载流子俘获的热激活演化到多重核/壳量子点中载流子的纵向光学（LO）声子辅助热逃逸。在具有厚 CdS 单壳和 CdS/ZnCdS/ZnS 多壳的核/壳 QD 中，可以清楚地观察到 PL 强度随着温度的升高而增加。 PL 增强被认为来自于 CdSe/CdS 界面上电势深度约为 30 meV 的电荷载流子的离域。实验结果表明，CdSe 核 CdS/CdZnS/ZnS-多壳量子点中 PL 量子效率的提高可以从以下几个方面来理解：
The photoluminescence (PL) spectra of CdSe-core CdS/CdZnS/ZnS-multishell quantum dots (QDs) were studied to understand the radiative and nonradiative relaxation processes in the temperature range from 80 to 360 K. The mechanism of temperature-dependent nonradiative relaxation processes in the CdSe QDs with changing the shell structures was found to evolve from thermal activation of carrier trapping by surface defects/traps in CdSe core QDs to the multiple longitudinal-optical (LO) phonon-assisted thermal escape of carriers in the core/shell QDs. An increase in PL intensity with increasing temperature was clearly observed in the core/shell QDs with a thick CdS monoshell and a CdS/ZnCdS/ZnS multishell. The PL enhancement was considered to come from delocalization of charge carriers localized at the CdSe/CdS interface with the potential depth of ∼30 meV. The experimental results indicated that the improvement of PL quantum efficiency in CdSe-core CdS/CdZnS/ZnS-multishell QDs could be understood in terms of t...