He Sheng, Ni Anji, Gebre Sara T, Hang Rui, McBride James R, Kaledin Alexey L, Yang Wenxing, Lian Tianquan
Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States.
Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
J Am Chem Soc. 2024 Sep 11;146(36):24925-24934. doi: 10.1021/jacs.4c06110. Epub 2024 Aug 27.
Doping of colloidal nanocrystals offers versatile ways to improve their optoelectronic properties, with potential applications in photocatalysis and photovoltaics. However, the precise role of dopants on the interfacial charge transfer properties of nanocrystals remains poorly understood. Here, we use a Cu-doped InP@ZnSe quantum dot as a model system to investigate the dopant effects on both the intrinsic photophysics and their interfacial charge transfer by combining time-resolved transient absorption and photoluminescent spectroscopic methods. Our results revealed that the Cu dopant can cause the generation of the self-trapped exciton, which prolongs the exciton lifetime from 48.3 ± 1.7 to 369.0 ± 4.3 ns, facilitating efficient charge separation to slow electron and hole acceptors. However, hole localization into the Cu site alters their energetic levels, slowing hole transfer and accelerating charge recombination loss. This double-edged sword role of dopants in charge transfer properties is important in the future design of nanocrystals for their optoelectronic and photocatalytic applications.
胶体纳米晶体的掺杂提供了多种改善其光电性能的方法，在光催化和光伏领域具有潜在应用。然而，掺杂剂对纳米晶体界面电荷转移性质的确切作用仍知之甚少。在此，我们使用铜掺杂的InP@ZnSe量子点作为模型系统，通过结合时间分辨瞬态吸收和光致发光光谱方法，研究掺杂剂对其本征光物理性质及其界面电荷转移的影响。我们的结果表明，铜掺杂剂可导致自陷激子的产生，使激子寿命从48.3±1.7 ns延长至369.0±4.3 ns，促进了向慢速电子和空穴受体的有效电荷分离。然而，空穴定域到铜位点会改变其能级，减缓空穴转移并加速电荷复合损失。掺杂剂在电荷转移性质方面的这种双刃剑作用，对于未来纳米晶体在光电和光催化应用中的设计至关重要。
