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.
关键词：
