Article Title

Charge transfer and retention in directly coupled Au-CdSe nanohybrids

Authors

Bo Gao, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Yue Lin, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Sijie Wei, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Jie Zeng, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA
Yuan Liao, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Liuguo Chen, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
David Goldfeld, Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA
Xiaoping Wang, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Yi Luo, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Zhenchao Dong, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China
Jianguo Hou, Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China, Hefei, Anhui 230026, China

Keywords

Hybrid nanocrystals, time-resolved photoluminescence, charge transfer, charge retention

Abstract

The energy and charge transfer dynamics of directly coupled Au–CdSe hybrid nanocrystals have been studied using time-resolved photoluminescence (PL) techniques. The PL of such nanohybrids was found to be quenched dramatically compared to that of both CdSe quantum dots and mixtures of CdSe quantum dots with Au nanoparticles. Fluorescence decay curves of the Au–CdSe nanohybrids show three distinct decay channels with the fastest one associated with the transfer of electrons from the CdSe portion to the Au portion. The holes on the CdSe portion created by such charge transfer were then quickly taken away by the solution, while the electrons on the Au portion slowly leaked into the solution as well, thus serving as a reductant for redox reactions. Using a model reaction based on the reduction of methylene blue by the leaking electrons, our photocatalytic experiments indicate that the electrons can be temporarily retained in the Au portion (most likely at the Au–capping agent interface) for a dramatically long timescale, up to 100 min. Finally, by merging all of the observations in the time-resolved PL measurements, we were able to figure out a relatively complete picture of charge transfer and retention in the Au–CdSe nanohybrids. This picture is expected to guide researchers in designing modern photocatalysts and solar cells constructed from nanoscale metal–semiconductor hybrids.

Graphical Abstract

DOI

https://doi.org/10.1007/s12274-011-0188-8

Publisher

Tsinghua University Press

Recommended Citation

Bo Gao,Yue Lin,Sijie Wei,Jie Zeng,Yuan Liao,Liuguo Chen,David Goldfeld,Xiaoping Wang,Yi Luo,Zhenchao Dong,Jianguo Hou, Charge transfer and retention in directly coupled Au-CdSe nanohybrids. NanoRes.2012, 5(2): 88–98