微秒
纳秒
载流子
材料科学
超快激光光谱学
光电子学
半导体
通量
分子物理学
分解水
载流子寿命
原子物理学
化学
光学
物理
激光器
硅
光催化
生物化学
催化作用
作者
Vikas Nandal,Ryota Shoji,Hiroyuki Matsuzaki,Akihiro Furube,Lihua Lin,Takashi Hisatomi,M. Kaneko,Koichi Yamashita,Kazunari Domen,Kazuhiko Seki
标识
DOI:10.1038/s41467-021-27199-3
摘要
Oxysulfide semiconductor, Y2Ti2O5S2, has recently discovered its exciting potential for visible-light-induced overall water splitting, and therefore, imperatively requires the probing of unknown fundamental charge loss pathways to engineer the photoactivity enhancement. Herein, transient diffuse reflectance spectroscopy measurements are coupled with theoretical calculations to unveil the nanosecond to microsecond time range dynamics of the photogenerated charge carriers. In early nanosecond range, the pump-fluence-dependent decay dynamics of the absorption signal is originated from the bimolecular recombination of mobile charge carriers, in contrast, the power-law decay kinetics in late microsecond range is dominated by hole detrapping from exponential tail trap states of valence band. A well-calibrated theoretical model estimates various efficiency limiting material parameters like recombination rate constant, n-type doping density and tail-states parameters. Compared to metal oxides, longer effective carrier lifetime ~6 ns is demonstrated. Different design routes are proposed to realize efficiency beyond 10% for commercial solar-to-hydrogen production from oxysulfide photocatalysts.
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