[1] [1] Jie Zhang, Xin Wang, Weitao Zheng et al.. Stucture and luminescence properties of TiO2∶Er3+ nanocrystals annealed at different temperatures[J]. Mater. Lett., 2007, 61: 1658～1661

[2] [2] Qingkun Shang, Hui Yu, Xianggui Kong et al.. Green and red up-conversion emissions of Er3+-Yb3+ co-doped TiO2 nanocrystals prepared by sol-gel method[J]. J. Luminescence, 2008, 128: 1211～1216

[3] [3] D. M. Shi, Q. Y. Zhang, G. F. Yang et al.. Frequency upconversion luminescence in Tm3+/Yb3+- and Ho3+/Yb3+-codoped Ga2O3-GeO2-Bi2O3-PbO glasses[J]. J. Alloys and Compounds, 2008, 466: 373～376

[4] [4] Qiuhua Nie, Xiejie Li, Shixun Dai et al.. Energy transfer and upconversion luminescence in Tm3+/Yb3+ co-doped lanthanum-zinc-lead-tellurite glasses[J]. J. Luminescence, 2008, 128: 135～141

[5] [5] Shiqing Xu, Hongping Ma, Dawei Fang et al.. Tm3+/Er3+/Yb3+-codoped oxyhalide tellurite glasses as materials for three-dimensional display[J]. Mater. Lett., 2004, 59: 3066～3068

[6] [6] Meisong Liao, Lili Hu, Yongzheng Fang et al.. Upconversion properties of Er3+, Yb3+ and Tm3+ codoped fluorophosphate glasses[J]. Spectrochimica Acta Part A, 2007, 68: 531～535

[7] [7] Liqiong An, Jian Zhang, Min Liu et al.. Upconversion luminescence of Tm3+ and Yb3+-codoped lutetium oxide nanopowders[J]. J. Alloys and Compounds, 2008, 451: 538～541

[8] [8] Hai Guo. Green and red upconversion luminescence in CeO2∶Er3+ powders produced by 785 nm laser[J]. J. Solid State Chemistry, 2007, 180: 127～131

[9] [9] Hai Guo, Ning Dong, Min Yin et al.. Visible upconversion in rare earth ion-doped Gd2O3 nanocrystals[J]. J. Phys. Chem. B, 2004, 108: 19205～19209

[10] [10] Langying Hu, Hongwei Song, Guohui Pan et al.. Photoluminescence properties of samarium-doped TiO2 semiconductor nanocrystalline powders[J]. J. Luninescence, 2007, 127: 371～376

[11] [11] San-Yuan Chen, Chu-Chi Ting, Wen-Feng Hsieh. Comparison of visible fluorescence properties between sol-gel derived Er3+-Yb3+ and Er3+-Y3+ co-doped TiO2 films[J]. Thin Solid Films, 2003, 434: 171～177

[12] [12] Yao Shuping. Preparation and up-conversion luminescence of Er3+, and Er3+and Yb3+ doped TiO2 synthesized by sol-gel method[D]. Dalian: Dalian University of Technology, 2006. 17

[13] [13] A. Patra, C. S. Friend, R. Kapoor et al.. Effect of crystal nature on upconversion luminescence in Er3+∶ZrO2 nanocrystals[J]. Appl. Phys. Lett., 2003, 83(2): 284

[14] [14] Xiaojiang Pei, Yanbing Hou, Suling Zhao et al.. Frequency upconversion of Tm3+ and Yb3+ codoped YLiF4 synthesized by hydrothermal method[J]. Materials Chemistry and Physics, 2005, 90: 270～274

[15] [15] Guo Hai, Dong Ning, Zhou Minjie et al.. Visible upconversion luminescence in Er3+/Yb3+-codoped SrTiO3 ultra-fine powders[J]. Chinese J. Luninescence, 2006, 27(1): 53～58