Zhang Chi, Lian Linyuan, Yang Zhaoliang, Zhang Jianbing, Zhu Haiming
Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry , Zhejiang University , Hangzhou , Zhejiang 310027 , China.
School of Optical and Electronic Information , Huazhong University of Science and Technology , 1037 Luoyu Road , Wuhan , Hubei 430074 , China.
J Phys Chem Lett. 2019 Dec 19;10(24):7665-7671. doi: 10.1021/acs.jpclett.9b03293. Epub 2019 Dec 2.
0D-2D mixed-dimensional hybrid structures, which combine tunable optical properties of 0D quantum dots (QDs) and high transport mobilities of 2D layered materials, have shown great potential in optoelectronic applications. Understanding charge transfer dynamics at the 0D-2D interface is essential but still lacking. Here, using PbS QD/WSe system, by simply controlling PbS QD size, we show a tunable hole transfer (HT) rate by more than 4 orders of magnitude (from ∼1 ns to <100 fs) and, interestingly, transition from the weak to strong coupling regime due to quantum confinement effect. In contrast to reported layer-dependent energy transfer dynamics, we observe a robust HT rate against WSe layer number, which can be ascribed to a subtle change of WSe valence band structure with layer number. Our results are important to not only fundamental understanding of charge transfer behavior at nanoscale low-dimensional interface but also help design next-generation mixed-dimensional optoelectronic devices.
零维-二维混合维杂化结构结合了零维量子点（QD）的可调光学性质和二维层状材料的高迁移率，在光电子应用中显示出巨大潜力。了解零维-二维界面处的电荷转移动力学至关重要，但目前仍缺乏相关研究。在此，我们使用硫化铅量子点/硒化钨体系，通过简单控制硫化铅量子点的尺寸，展示了可调的空穴转移（HT）速率，其变化超过4个数量级（从约1纳秒到小于100飞秒），并且有趣的是，由于量子限制效应，从弱耦合 regime 过渡到强耦合 regime。与报道的依赖层的能量转移动力学不同，我们观察到空穴转移速率对硒化钨层数具有鲁棒性，这可归因于硒化钨价带结构随层数的细微变化。我们的结果不仅对于在纳米尺度低维界面处电荷转移行为的基础理解很重要，而且有助于设计下一代混合维光电器件。
