期刊
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
卷 24, 期 8, 页码 4743-4750出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/d1cp04248c
关键词
-
资金
- NSFC [12047546, 11974322, 11620101003, 11704363]
- China Postdoctoral Science Foundation [2020M682326]
- National Key Foundation of China, Department of Science and Technology [2017YFA0204904]
- DOE Office of Biological and Environmental Research
The presence of oxygen vacancies in rutile TiO2 enhances the electron-hole recombination process and leads to increased charge delocalization at higher temperatures, resulting in stronger nonadibatic coupling.
The photoexcited carrier lifetime in semiconductors plays a crucial role in solar energy conversion processes. The defects or impurities in semiconductors are usually proposed to introduce electron-hole (e-h) recombination centers and consequently reduce the photoexcited carrier lifetime. In this report, we investigate the effects of oxygen vacancies (O-V) on the carrier lifetime in rutile TiO2, which has important applications in photocatalysis and photovoltaics. It is found that an O-V introduces two excess electrons which form two defect states in the band gap. The lower state is localized on one Ti atom and behaves as a small polaron, and the higher one is a hybrid state contributed by three Ti atoms around the O-V. Both the polaron and hybrid states exhibit strong electron-phonon (e-ph) coupling and their charge distributions become more and more delocalized when the temperature increases from 100 to 700 K. Such strong e-ph coupling and charge delocalization enhance the nonadibatic coupling between the electronic states along the hole relaxation path, where the defect states behave as intermediate states, leading to a distinct acceleration of e-h recombination. Our study provides valuable insights to understand the role of defects on photoexcited carrier lifetime in semiconductors.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据