Shi Rui, Lin Litian, Wang Zijun, Zou Qilin, Mudring Anja-Verena
Intelligent Advanced Materials, Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C 8000, Denmark.
State Key Laboratory of Rare Metals Separation and Comprehensive Utilization, Guangdong Provincial Key Laboratory of Rare Earth Development and Application, Institute of Resources Utilization and Rare Earth Development, Guangdong Academy of Sciences, Guangzhou 510651, China.
J Am Chem Soc. 2024 May 1;146(17):11924-11931. doi: 10.1021/jacs.4c00052. Epub 2024 Apr 16.
Ln-doped (Ln = lanthanide) nanocrystals are garnering strong interest for their potential as optical materials in various applications. For that reason, a thorough understanding of photophysical processes and ways to tune them in these materials is of great importance. This study, using Eu-doped SrYF as a well-suited model system, underscores the (not unexpected) significance of surface site occupation of Ln and also challenges the prevailing views about their contribution to the luminescence of the system. High-temperature cation exchange and epitaxial shell growth allow nanocrystals to exclusively feature Eu residing at the surface or in the interior, thereby separating their spectral responses. Meticulous experiments reveal that nanocrystals with high doping concentrations exhibit luminescence primarily from surface Eu, in contrast to the popular belief that luminescence from surface Ln is largely negligible. The present study shows, on the one hand, the necessity to revise common ideas and also reveals the potential for manipulating the luminescence of such materials through an, until now, unperceived way of surface engineering.
镧系元素（Ln）掺杂的纳米晶体因其在各种应用中作为光学材料的潜力而备受关注。因此，深入了解这些材料中的光物理过程及其调控方法至关重要。本研究以铕（Eu）掺杂的SrYF作为一个合适的模型体系，强调了Ln表面位点占据的（不出所料的）重要性，同时也对关于它们对体系发光贡献的主流观点提出了挑战。高温阳离子交换和外延壳层生长使纳米晶体能够仅让Eu位于表面或内部，从而分离它们的光谱响应。细致的实验表明，与普遍认为表面Ln的发光基本可忽略不计的观点相反，高掺杂浓度的纳米晶体主要表现出来自表面Eu的发光。本研究一方面表明有必要修正常见观点，同时也揭示了通过一种迄今为止未被察觉的表面工程方式来操纵此类材料发光的潜力。
