Direct evidence of reversible energy transfer between Er3+ and Tm3+ ions in upconversion microcrystals
来源期刊:Journal of Rare Earths2015年第7期
论文作者:陈增辉 高永毅 谭丛兵 刘云新
文章页码:679 - 685
摘 要:Lanthanide doped Na YF4 microcrystals were synthesized via a facile hydrothermal method. Multicolor upconversion luminescence was observed in Na YF4 microcrystals doped with Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Er3+/Tm3+ under the excitation of 980 nm infrared light. Importantly, the excitation power density dependence of upconversion emission intensity indicated clearly the energy transfer from Tm3+ to Er3+ ions under the excitation of low power density(5×102–9×102 W/cm2). Meanwhile, the inverse energy transfer from Er3+ to Tm3+ ions under the excitation of relatively higher power density(4.1×104–4.9×104 W/cm2) was also revealed. This was a direct evidence for reversible energy transfer between Er3+ and Tm3+ ions. Under the excitation of high power density(4.1×104–4.9×104 W/cm2), dark sensitizers were also motivated so that the bottleneck effect of high concentration Yb3+ ion doping was broken. This was the main reason for realizing high upconversion efficiency of the samples with heavy doping of Yb3+ ion.
陈增辉,高永毅,谭丛兵,刘云新
Department of Physics and Electronic Science Hunan University of Science and Technology
摘 要:Lanthanide doped Na YF4 microcrystals were synthesized via a facile hydrothermal method. Multicolor upconversion luminescence was observed in Na YF4 microcrystals doped with Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Er3+/Tm3+ under the excitation of 980 nm infrared light. Importantly, the excitation power density dependence of upconversion emission intensity indicated clearly the energy transfer from Tm3+ to Er3+ ions under the excitation of low power density(5×102–9×102 W/cm2). Meanwhile, the inverse energy transfer from Er3+ to Tm3+ ions under the excitation of relatively higher power density(4.1×104–4.9×104 W/cm2) was also revealed. This was a direct evidence for reversible energy transfer between Er3+ and Tm3+ ions. Under the excitation of high power density(4.1×104–4.9×104 W/cm2), dark sensitizers were also motivated so that the bottleneck effect of high concentration Yb3+ ion doping was broken. This was the main reason for realizing high upconversion efficiency of the samples with heavy doping of Yb3+ ion.
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