Spectral characterization of LiYbF4upconverting nanoparticles
Spectral characterization of LiYbF4upconverting nanoparticles
复制标题
DOI：
10.1039/d0nr04357e
复制
发表时间：
2020-09-07
期刊：
影响因子：
6.7
通讯作者：
Vetrone, Fiorenzo
中科院分区：
文献类型：
--
作者：
Skripka, Artiom;Cheng, Ting;Vetrone, Fiorenzo
针对Yb ~（3+）基上转换稀土纳米粒子（RENP）的最新研究进展，我们系统地研究了不同掺杂量的Tm ~（3+）、Er ~（3+）、Ho ~（3+）的LiYbF_4：RE ~（3+）/LiYF（4）核壳型RENP的光谱特性。Tm 3 +-RENP显示出从紫外到近红外（NIR）的光致发光，并且这些RENP的主要高光子阶上转换发射可通过Tm（3+）掺杂来调谐。类似地，具有绿色和红色上转换的Er 3 +-和Ho 3 +-RENP显示出宽的颜色调谐，这取决于掺杂量和激发功率密度。从稳态功率图和光致发光衰减的研究，我们已经观察到各自的上转换光子的顺序和平均寿命的变化，证明了一些交叉弛豫过程发生在较高的RE（3+）掺杂浓度。特别是在Tm 3 +-RENP的情况下，交叉弛豫促进了UV和蓝色光谱区域中的四光子和五光子阶上转换发射。高阶上转换发射的量子产率与经典的Yb 3 +/Tm 3+掺杂系统相当，但由于LiYbF（4）主体中的大量敏化剂离子，这些RENP预计会更亮，因此更适合于诸如受控药物递送或光遗传学的应用。总的来说，LiYbF 4：RE 3 +/LiYF（4）RENP是有效产生高阶上转换发射的有希望的系统，这归因于Yb（3+）网络内的激发能量限制及其对激活剂掺杂剂的有效功能。
In light of the recent developments on Yb3+-based upconverting rare-earth nanoparticles (RENPs), we have systematically explored the spectral features of LiYbF4:RE3+/LiYF(4)core/shell RENPs doped with various amounts of Tm3+, Er3+, or Ho3+. Tm3+-RENPs displayed photoluminescence from the UV to near-infrared (NIR), and the dominant high-photon-order upconversion emission of these RENPs was tunable by Tm(3+)doping. Similarly, Er3+- and Ho3+-RENPs with green and red upconversion showed wide color tuning, depending on the doping amount and excitation power density. From steady-state power plot and photoluminescence decay studies we have observed respective changes in upconversion photon order and average lifetime that attest to a number of cross-relaxation processes occurring at higher RE(3+)doping concentration. Particularly in the case of Tm3+-RENPs, cross-relaxation promotes four- and five-photon order upconversion emission in the UV and blue spectral regions. The quantum yield of high-order upconversion emission was on par with classic Yb3+/Tm3+-doped systems, yet due to the high number of sensitizer ions in the LiYbF(4)host these RENPs are expected to be brighter and thus better suited for applications such as controlled drug delivery or optogenetics. Overall, LiYbF4:RE3+/LiYF(4)RENPs are promising systems to effectively generate high-order upconversion emissions, owing to excitation energy confinement within the Yb(3+)network and its efficient funneling to the activator dopants.