Enhanced ultraviolet upconversion in YF3:Yb3+/Tm3+ nanocrystals
来源期刊：JOURNAL OF RARE EARTHS2009年第2期
论文作者：ZHU Peifen WEI Guodong QIN Weiping WANG Lili ZHANG Daisheng WANG Guofeng DING Fuheng
Key words：upconversion luminescence; nanocrystals; Judd-Ofelt parameter; rare earths;
Abstract: Unusual intense infrared-to-ultraviolet upconversion luminescence was observed in YF3:Yb3+(20%)/Tm3+(1%) nanocrystals under 980 nm excitation. The intense ultraviolet emissions (1I6→3H6, 1I6→3F4, and 1D2→3H6) were affirmed arising from the excitation processes of five-photon and four-photon. In comparison with the bulk sample with the same chemical compositions, ultraviolet upconversion lumi-nescence 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 (Tm3+): 3H4→1D2 (Tm3+).
ZHU Peifen1，WEI Guodong1，QIN Weiping1，WANG Lili1，ZHANG Daisheng1，WANG Guofeng1，DING Fuheng1
(1.State Key Laboratory on Integrated Optoelectronics,College of Electronic Science & Engineering,Jilin University,Changchun 130012,China)
Abstract:Unusual intense infrared-to-ultraviolet upconversion luminescence was observed in YF3:Yb3+(20%)/Tm3+(1%) nanocrystals under 980 nm excitation. The intense ultraviolet emissions (1I6→3H6, 1I6→3F4, and 1D2→3H6) were affirmed arising from the excitation processes of five-photon and four-photon. In comparison with the bulk sample with the same chemical compositions, ultraviolet upconversion lumi-nescence 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 (Tm3+): 3H4→1D2 (Tm3+).
Key words:upconversion luminescence; nanocrystals; Judd-Ofelt parameter; rare earths;
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