Strong dependence of upconversion luminescence on doping concentration in holmium and ytterbium co-doped Y_2O_3 phosphor

• Published in: Journal of rare earths Vol. 29; no. 6; pp. 536 - 539
• Main Author: 韦先涛 李勇 程学瑞 陈永虎 尹民
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2011
• Subjects: holmium; rare earths; sol-gel; upconversion luminescence; Y 2O 3; 上转换发光; 最佳掺杂浓度; 浓度依赖性; 激光二极管; 激光激发; 绿光发射; 能量传递过程; 荧光粉; upconversion luminescence; Y 2O 3; holmium; sol-gel; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(10)60493-0

Under the excitation of 980 nm diode laser, intense green emission （5F4＋5S2–5I8） of Ho3＋ was observed in Ho3＋ and Yb3＋ co-doped cubic Y2O3. The doping concentration and laser power dependence of the upconverted emission were studied. The decay curves of 5F4＋5S2 emission of Ho3＋ under the excitation of 355 nm pulse laser were measured to investigate the energy transfer process between Ho3＋ and Yb3＋. The results indicated that two-photon process was responsible for the upconversion （UC） emission. The Ho3＋ concentration of 0.04 mol.% and the Yb3＋ concentration of 5 mol.% were determined to be the best value for the strongest Ho3＋ emission under the excitation of 980 nm light. The cross-relaxation between two neighboring Ho3＋ ions and the back energy transfer from Ho3＋ to Yb3＋ were important factors for determin- ing the optimal doping concentration. This material was a promising candidate for the application in biomedical fluorescent labels for the intense green emission upon excitation of near-infrared （NIR） light.