https://scholars.lib.ntu.edu.tw/handle/123456789/403277
標題: | Tunable Nonthermal Distribution of Hot Electrons in a Semiconductor Injected from a Plasmonic Gold Nanostructure | 作者: | Scott Kevin Cushing CHIH-JUNG CHEN Chung Li Dong Xiang-Tian Kong Alexander O. Govorov RU-SHI LIU Nianqiang Wu |
關鍵字: | hot carriers; photocatalysis; photovoltaics; plasmonics; X-ray absorption | 公開日期: | 2018 | 出版社: | American Chemical Society ({ACS}) | 來源出版物: | ACS Nano | 摘要: | For semiconductors photosensitized with organic dyes or quantum dots, transferred electrons are usually considered thermalized at the conduction band edge. This study suggests that the electrons injected from a plasmonic metal into a thin semiconductor shell can be nonthermal with energy up to the plasmon frequency. In other words, the electrons injected into the semiconductor are still hot carriers. Photomodulated X-ray absorption measurements of the Ti L2,3 edge are compared before and after excitation of the plasmon in Au@TiO2 core-shell nanoparticles. Comparison with theoretical predictions of the X-ray absorption, which include the heating and state-filling effects from injected hot carriers, suggests that the electrons transferred from the plasmon remain nonthermal in the ∼10 nm TiO2 shell, due in part to a slow trapping in defect states. By repeating the measurements for spherical, rod-like, and star-like metal nanoparticles, the magnitude of the nonthermal distribution, peak energy, and number of injected hot electrons are confirmed to be tuned by the plasmon frequency and the sharp corners of the plasmonic nanostructure. The results suggest that plasmonic photosensitizers can not only extend the sunlight absorption spectral range of semiconductor-based devices but could also result in increased open circuit voltages and elevated thermodynamic driving forces for solar fuel generation in photoelectrochemical cells. © 2018 American Chemical Society. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/403277 | DOI: | 10.1021/acsnano.8b02939 | SDG/關鍵字: | Core shell nanoparticles; Electrons; Gold; Metal nanoparticles; Oil field development; Open circuit voltage; Photoelectrochemical cells; Photosensitizers; Plasmonics; Plasmons; Semiconductor quantum dots; Titanium dioxide; X ray absorption; Conduction band edge; Gold nanostructures; Plasmon frequency; Plasmonic nanostructures; Spectral range; State filling effect; Thermodynamic driving forces; Thin semiconductor; Hot electrons |
顯示於: | 化學系 |
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