Yang Dandan, Peng Zixing, Zhan Qiuqiang, Huang Xiongjian, Peng Xingyun, Guo Xin, Dong Guoping, Qiu Jianrong
State Key Laboratory of Luminescent Materials and Devices, and Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China.
Small. 2019 Oct;15(43):e1904298. doi: 10.1002/smll.201904298. Epub 2019 Sep 6.
Precise knowledge about optical and structural performance of individual rare earth (RE)-doped particles is extremely important for the optimization of luminescent particles and for fully exploiting their capability as multifunctional probes for interdisciplinary applications. In this work, optical and structural anisotropy of individual particles through RE-doped single fluoride microcrystals with controllable morphology is reported. Unique luminescent phenomena, for example, white light-emission from Pr at single particle level and different photoluminescent spectra variation dependence on excitation polarization orientation at different excitation direction are observed upon excitation with a 980 nm linearly polarized laser. Based on the analysis of local site symmetry and electron cloud distribution of REs in hexagonal structure by density functional theory calculations, an exciting mechanism of excitation polarization response anisotropy is given for the first time, providing a guidance for emission polarization simultaneously. The structural anisotropy is presented in Raman spectra with obvious differing Raman curves, revealing the reason why there are differences between powder groups. Taking advantage of anisotropic crystals, potential applications in microscopic multi-information transportation are suggested for the optical and structural performance anisotropy from RE-doped fluoride single nano/microcrystals to ordered nano/microcrystal arrays, such as local rate probing in a flowing liquid.
精确了解单个稀土（RE）掺杂粒子的光学和结构性能对于优化发光粒子以及充分发挥其作为跨学科应用多功能探针的能力极为重要。在这项工作中，报道了通过具有可控形态的RE掺杂单氟化物微晶实现的单个粒子的光学和结构各向异性。在用980 nm线偏振激光激发时，观察到了独特的发光现象，例如在单个粒子水平上Pr的白光发射以及在不同激发方向上不同的光致发光光谱变化对激发偏振方向的依赖性。基于密度泛函理论计算对六方结构中RE的局域位点对称性和电子云分布的分析，首次给出了激发偏振响应各向异性的激发机制，同时也为发射偏振提供了指导。拉曼光谱呈现出结构各向异性，拉曼曲线明显不同，揭示了粉末组之间存在差异的原因。利用各向异性晶体，从RE掺杂氟化物单纳米/微晶到有序纳米/微晶阵列的光学和结构性能各向异性被建议用于微观多信息传输的潜在应用，例如在流动液体中的局部速率探测。
