Enhanced ultraviolet upconversion in YF_3:Yb^(3+)/Tm^(3+) nanocrystals  

作　　者：王国凤 秦伟平 王丽丽 尉国栋 朱培芬 张代生 丁福恒 

机构地区：[1]State Key Laboratory on Integrated Optoelectronics,College of Electronic Science & Engineering,Jilin University,Changchun 130012,China

出　　处：《Journal of Rare Earths》2009年第2期330-333,共4页稀土学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (10474096 and 50672030)

摘　　要：Unusual intense infrared-to-ultraviolet upconversion luminescence was observed in YF3：yb3＋（20%）/Tm3＋（1%） nanocrystals under 980 ran excitation. The intense ultraviolet emissions （1I6→^3H6, ^1I6→3F4, and ^1D2→^3H6） were affirmed arisillg from the excitation processes of five-photon and four-photon. In comparison with the bulk sample with the same chemical compositions, ultraviolet upconversion luminescence of the nanocrystals was markedly enhanced. Spectral analysis indicated that the enhancement was attributed to the decrease of Judd-Ofelt parameter Ω2, which precluded the transition rate from 3F2 to 3F4, enhanced the energy transfer process and populated the ^1D2 level： ^3F2→^3H6 （Tm^3＋）： 3H4→^1D2 （Tm^3＋）.Unusual intense infrared-to-ultraviolet upconversion luminescence was observed in YF3：yb3＋（20%）/Tm3＋（1%） nanocrystals under 980 ran excitation. The intense ultraviolet emissions （1I6→^3H6, ^1I6→3F4, and ^1D2→^3H6） were affirmed arisillg from the excitation processes of five-photon and four-photon. In comparison with the bulk sample with the same chemical compositions, ultraviolet upconversion luminescence of the nanocrystals was markedly enhanced. Spectral analysis indicated that the enhancement was attributed to the decrease of Judd-Ofelt parameter Ω2, which precluded the transition rate from 3F2 to 3F4, enhanced the energy transfer process and populated the ^1D2 level： ^3F2→^3H6 （Tm^3＋）： 3H4→^1D2 （Tm^3＋）.

关 键 词：apconversion luminescence NANOCRYSTALS Judd-Ofelt parameter rare earths 

分 类 号：TB383.1[一般工业技术—材料科学与工程]