| Autor: |
Shi R; Intelligent Advanced Materials, Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C 8000, Denmark., Lin L; 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., Wang Z; IMRB, Université Paris Est Créteil, INSERM U955, CNRS, EMR 7000, 94010 Créteil, France., Zou Q; Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, IP Paris, 91128 Palaiseau, France., Mudring AV; Intelligent Advanced Materials, Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C 8000, Denmark.; Department of Physics, Umeå University, Linnaeus väg 24, 901 87 Umeå, Sweden. |
| Abstrakt: |
Ln 3+ -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 3+ -doped Sr 2 YF 7 as a well-suited model system, underscores the (not unexpected) significance of surface site occupation of Ln 3+ 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 3+ 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 3+ , in contrast to the popular belief that luminescence from surface Ln 3+ 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. |
