Chiral quantum dots (QDs) are promising materials applied in many areas, such as chiral molecular recognition and spin selective filter for charge transport, and can be prepared by facile ligand exchange approaches. However, ligand exchange leads to an increase in surface defects and reduces the efficiencies of radiative recombination and charge transport, which restricts further applications. Here, we investigate the light-induced photoluminescence (PL) enhancement in chiral L- and D-cysteine CdSe QD thin films, providing a strategy to increase the PL. The PL intensity of chiral CdSe QD films can be significantly enhanced over 100 times by continuous UV laser irradiation, indicating a strong passivation of surface defects upon laser irradiation. From the comparative measurements of the PL intensity evolutions in vacuum, dry oxygen, air, and humid nitrogen atmospheres, we conclude that the mechanism of PL enhancement is photo-induced surface passivation with the assistance of water molecules.

中文翻译：

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手性 CdSe 量子点薄膜中的光诱导光致发光增强

手性量子点（QD）是一种有前景的材料，可应用于许多领域，例如手性分子识别和用于电荷传输的自旋选择性过滤器，并且可以通过简便的配体交换方法制备。然而，配体交换导致表面缺陷增加，降低辐射复合和电荷传输效率，限制了其进一步应用。在这里，我们研究了手性 L-和 D-半胱氨酸 CdSe QD 薄膜的光诱导光致发光 (PL) 增强，提供了增加 PL 的策略。通过连续紫外激光照射，手性 CdSe QD 薄膜的 PL 强度可以显着增强 100 倍以上，表明激光照射后表面缺陷的强烈钝化。通过对真空、干氧、空气和潮湿氮气气氛中PL强度演变的比较测量，我们得出结论，PL增强的机制是在水分子的帮助下光致表面钝化。