Weakly Confined Semiconductor Nanocrystals Excel in Photochemical and Optoelectronic Properties: Evidence from Single-Dot Studies

作者：Haixin Lei, Liulin Lv, Xionglin Zhou, Shaojie Liu, Meiyi Zhu, Huifeng Wang, Haiyan Qin, Qun Fang, Xiaogang Peng · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.4c06993 · 被引用次数：7 · 研究领域：Quantum Dots Synthesis And Properties、Chalcogenide Semiconductor Thin Films、Nanocluster Synthesis and Applications

Single-molecule spectroscopy offers state-resolved measurements on charge-transfer reactions of single semiconductor nanocrystals, leading to the discovery of up to six single-charge transfer reactions with seven transient states for single CdSe/CdS core/shell nanocrystals with water (or oxygen) as the hole (or electron) acceptors. Kinetic rates of three photoinduced single-hole transfer reactions decrease significantly upon increasing the number of excess electrons in a nanocrystal, mainly due to efficient Auger nonradiative recombination of the charged single excitons. Conversely, the kinetic rates of three single-electron transfer reactions of an unexcited nanocrystal increase proportionally to the number of excess electrons in it. Results here reveal that charge-transfer reactions of nanocrystals, at the center of nearly all their functions, could only be deciphered at a state-resolved level on a single nanocrystal. Size-dependent studies validate the weakly confined semiconductor nanocrystals, instead of strongly confined ones (quantum dots), as optimal candidates for photochemical and optoelectronic applications.