Temperature-Dependent Photoluminescence of Ag2Se Quantum Dots
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- 作者：Changyin Ji ; Yu Zhang ; Tieqiang Zhang ; Wenyan Liu ; Xiaoyu Zhang ; Hongzhi Shen ; Yu Wang ; Wenzhu Gao ; Yiding Wang ; Jun Zhao ; William W. Yu
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：June 18, 2015
- 年：2015
- 卷：119
- 期：24
- 页码：13841-13846
- 全文大小：353K
- ISSN：1932-7455
文摘
The time-resolved photoluminescence spectroscopy was employed to analyze the optical properties of Ag2Se quantum dots with different diameters at temperatures of 80鈥?60 K. The photoluminescence lifetime measurement disclosed that in the low-energy electronic structure there were two dominating emissive 鈥渋n-gap鈥?states associated with surface defect and intrinsic states, which were further confirmed by Gaussian fitting of the photoluminescence spectra. The temperature-dependent emission peak energy was fitted to phenomenological equations to extract the average phonon energy, the Huang鈥揜hys factor, and the excitonic acoustic phonon coupling coefficient. The relatively large phonon energy and small Huang鈥揜hys factor were demonstrated, which induced the small variation of emission peak energy in the low-temperature range. Meanwhile, the photoluminescence line width increased with temperature and was analyzed based on the standard equation describing the temperature dependence of the width of the ground state exciton. The variation of both the photoluminescence peak and line broadening was mostly due to the exciton to acoustic phonon coupling.