Yuan Maohui, Yang Zining, Yang Xu, Wang Linxuan, Wang Rui, Lan Sheng, Han Kai, Wang Hongyan, Xu Xiaojun
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China.
Department of Physics and Chemistry, PLA Army Academy of Special Operations, Guangzhou, 510507, China.
Nanoscale Res Lett. 2022 Mar 26;17(1):38. doi: 10.1186/s11671-021-03649-1.
Controlling the upconversion luminescence (UCL) intensity ratio, especially pumped at 808 nm, is of fundamental importance in biological applications due to the water molecules exhibiting low absorption at this excitation wavelength. In this work, a series of β-NaYbF:Er microrods were synthesized by a simple one-pot hydrothermal method and their intense green (545 nm) and red (650 nm) UCL were experimentally investigated based on the single-particle level under the excitation of 808 nm continuous-wave (CW) laser. Interestingly, the competition between the green and red UCL can be observed in highly Yb-doped microcrystals as the excitation intensity gradually increases, which leads to the UCL color changing from green to orange. However, the microcrystals doped with low Yb concentration keep green color which is independent of the excitation power. Further investigations demonstrate that the cross-relaxation (CR) processes between Yb and Er ions result in the UCL competition.
控制上转换发光（UCL）强度比，尤其是在808nm泵浦时，在生物应用中至关重要，因为水分子在该激发波长下吸收较低。在本工作中，通过简单的一锅水热法合成了一系列β-NaYbF:Er微棒，并在808nm连续波（CW）激光激发下基于单粒子水平对其强烈的绿色（545nm）和红色（650nm）UCL进行了实验研究。有趣的是，随着激发强度逐渐增加，在高Yb掺杂的微晶中可以观察到绿色和红色UCL之间的竞争，这导致UCL颜色从绿色变为橙色。然而，低Yb浓度掺杂的微晶保持绿色，且与激发功率无关。进一步研究表明，Yb和Er离子之间的交叉弛豫（CR）过程导致了UCL竞争。
