Defective Nature of CdSe Quantum Dots Embedded in Inorganic Matrices,Journal of the American Chemical Society

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Defective Nature of CdSe Quantum Dots Embedded in Inorganic Matrices
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2022-06-17 , DOI: 10.1021/jacs.2c03039
Wenke Li _{1,

2} , Kai Li ₁ , Xiujian Zhao ₁ , Chao Liu ₁ , François-Xavier Coudert ₂

Affiliation

Quantum dots (QDs) embedded in inorganic matrices have been extensively studied for their potential applications in lighting, displays, and solar cells. While a significant amount of research studies focused on their experimental fabrication, the origin of their relatively low photoluminescence quantum yield has not been investigated yet, although it severely hinders practical applications. In this study, we use time-dependent density functional theory (TDDFT) to pinpoint the nature of excited states of CdSe QDs embedded in various inorganic matrices. The formation of undercoordinated Se atoms and nonbridging oxygen atoms at the QD/glass interface is responsible for the localization of a hole wave function, leading to the formation of low-energy excited states with weak oscillator strength. These states provide pathways for nonradiative processes and compete with radiative emission. The photoluminescence performance is predicted for CdSe QDs in different matrices and validated by experiments. The results of this study have significant implications for understanding the underlying photophysics of CdSe QDs embedded in inorganic matrices that would facilitate the fabrication of highly luminescent glasses.

中文翻译：

嵌入无机基质中的 CdSe 量子点的缺陷性质

嵌入无机基质中的量子点 (QD) 因其在照明、显示器和太阳能电池中的潜在应用而被广泛研究。虽然大量的研究集中在它们的实验制造上，但它们相对较低的光致发光量子产率的原因尚未得到研究，尽管它严重阻碍了实际应用。在这项研究中，我们使用时间相关密度泛函理论 (TDDFT) 来确定嵌入各种无机基质中的 CdSe 量子点激发态的性质。在 QD/玻璃界面处形成欠配位的 Se 原子和非桥接氧原子是空穴波函数局域化的原因，导致形成具有弱振荡器强度的低能激发态。这些状态为非辐射过程提供了途径，并与辐射发射竞争。预测了不同基质中 CdSe 量子点的光致发光性能，并通过实验验证。这项研究的结果对于理解嵌入无机基质中的 CdSe 量子点的潜在光物理学具有重要意义，这将有助于制造高发光玻璃。

更新日期：2022-06-17

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