从n-Doped纳米晶体进行电荷转移:模仿多电子光催化中的中间事件
Junhui Wang1, Tao Ding1, Kaifeng Wu1
1State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China.
Journal of the American Chemical Society
|June 10, 2018
概括
在光催化中,量子点中的额外电子会产生带电激子,阻碍电荷转移并降低效率. 这项研究揭示了充电激子如何限制光催化性能.
科学领域:
- 光催化
- 量子点化学
- 电荷动力学
背景情况:
- 多电子光催化反应涉及从光收获器到催化剂的电荷转移.
- 在光收获器中,未被清除的电荷可以形成充电激子,使电荷提取复杂化.
- 充电式激子是光催化效率的潜在瓶.
研究的目的:
- 在光催化系统中研究充电激子的电荷动态.
- 量化预先存在的电荷对电荷分离和转移的影响.
- 了解多电子光催化物的效率限制.
主要方法:
- 硫化物 (CdS) 纳米晶体量子点 (QDs) 具有额外的电子.
- 从n-doped QD转移到附加的接受器的测量孔.
- 比较中性与带电激子的电荷分离产量和传输速率.
主要成果:
- 与中性激子 (98.4%) 相比,带电激子的增强衰变显著降低了电荷分离率 (68.6%).
- 在两个电子 (1290 ps) 与一个电子 (776 ps) 的存在下,孔转移速度较慢.
- 电荷分离状态的重组速率大约是充电激子的两倍.
结论:
- 带电激子是由未被清除的电荷形成的,是限制光催化效率的关键中间事件.
- 过多的电子阻碍了电荷转移并加速了电荷重组.
- 这项研究提供了通过管理激子状态来优化光催化过程的关键见解.
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