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The effect of Li on the spectrum of Er3+ in Li- and Er-codoped ZnO nanocrystals

Bai, Yunfeng and Wang, Yuxiao and Yang, Kun and Zhang, Xueru and Peng, Guanya and Song, Yinglin and Pan, Zhiyun and Wang, Chin Hsien (2008) The effect of Li on the spectrum of Er3+ in Li- and Er-codoped ZnO nanocrystals. JOURNAL OF PHYSICAL CHEMISTRY C, 112 (32). pp. 12259-12263.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/jp803373e

Abstract

Infrared-to-visible upconversion emission intensities are investigated in Li+ and Er3+ codoped ZnO nanocrystals. Li+ ions doped in ZnO/Er3+ nanocrystals can greatly enhance the upconversion emission intensity of Er3+ ions. The extended X-ray absorption fine structure spectroscopy data show that both the Er-O bond length and coordination number of the Er-Er bond have been altered by introducing Li+ ions in the ZnO/Er3+ nanocrystals. The variation of Er-O bond length leads to the change in the local asymmetry around Er3+ ions. Meanwhile, the greater coordination number of the Er-Er bond causes stronger interaction between neighboring Er3+ ions and, hence, strengthens the reaction Er3+ (F-4(7/2)) + Er3+ (I-4(1/2)) --> 2Er(3+) (F-4(9/2)). In this process,the F-4(9/2) state is a metastable state that could be excited to the H-2(9/2) state by absorbing one photon at high excitation power. Li+ ions also can reduce the OH groups in specimen, which is the other reason for enhancing the upconversion emission intensities.

Item Type:Article
Subjects:Physical Science > Photonics
ID Code:1871
Deposited By:Farnush Anwar
Deposited On:16 Dec 2008 10:47
Last Modified:16 Dec 2008 10:47

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