標題: Interfacial Charge Carrier Dynamics in Core-Shell Au-CdS Nanocrystals
作者: Yang, Ting-Ting
Chen, Wei-Ta
Hsu, Yung-Jung
Wei, Kung-Hwa
Lin, Tai-Yuan
Lin, Tai-Wei
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 8-Jul-2010
摘要: The interfacial charge carrier dynamics for core-shell Au-CdS nanocrystals with various shell thicknesses were investigated and presented. Due to the difference in band structures between Au and CdS, a pronounced photoinduced charge separation took place at the interface of Au and CdS, resulting in the electron-charged Au core and the hole-enriched CdS shell. The electron-charging of Au core in Au-CdS nanocrystals was revealed with the corresponding XPS analysis and photocurrent measurement. Time-resolved PL spectra were measured to quantitatively analyze the electron transfer event between CdS shell and Au core for Au-CdS nanocrystals. An increase in the electron-transfer rate constant was observed for Au-CdS nanocrystals with increasing shell thickness, probably due to the less pronounced electron hole interaction of thicker CdS, which enabled a fuller extent of participation of photoexcited electrons in the charge separation process. On the other hand, the hole-enriched CdS shell of Au-CdS nanocrystals upon light illumination was characterized with a photocatalytic process. The photocatalytic activity of Au-CdS nanocrystals was found to increase with increasing shell thickness, attributable to the greater capability of light absorption achieved by the extensive growth of the CdS shell. The correlation of photocatalytic activity with the shell thickness of Au-CdS nanocrystals corresponded well with that of the electron-transfer rate constant. As compared to the relevant commercial products like N-doped P-25 TiO(2), and CdS powders, the as-synthesized Au-CdS nanocrystals,exhibited superior photocatalytic performance under visible light illumination, demonstrating their potential as an effective visible-light-driven photocatalyst. Furthermore, the result of performance evaluation under natural sunlight shows that the present Au-CdS nanocrystals can be used as highly efficient photocatalysts which may practically harvest energy from sunlight.
URI: http://dx.doi.org/10.1021/jp103294c
http://hdl.handle.net/11536/5144
ISSN: 1932-7447
DOI: 10.1021/jp103294c
期刊: JOURNAL OF PHYSICAL CHEMISTRY C
Volume: 114
Issue: 26
起始頁: 11414
結束頁: 11420
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