Tuning upconversion through energy migration in core-shell nanoparticles
KAUST DepartmentImaging and Characterization Core Lab
Biological and Environmental Sciences and Engineering (BESE) Division
Chemical Science Program
Advanced Membranes and Porous Materials Research Center
Physical Sciences and Engineering (PSE) Division
Advanced Nanofabrication, Imaging and Characterization Core Lab
Nanostructured Functional Materials (NFM) laboratory
Permanent link to this recordhttp://hdl.handle.net/10754/561902
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AbstractPhoton upconversion is promising for applications such as biological imaging, data storage or solar cells. Here, we have investigated upconversion processes in a broad range of gadolinium-based nanoparticles of varying composition. We show that by rational design of a core-shell structure with a set of lanthanide ions incorporated into separated layers at precisely defined concentrations, efficient upconversion emission can be realized through gadolinium sublattice-mediated energy migration for a wide range of lanthanide activators without long-lived intermediary energy states. Furthermore, the use of the core-shell structure allows the elimination of deleterious cross-relaxation. This effect enables fine-tuning of upconversion emission through trapping of the migrating energy by the activators. Indeed, the findings described here suggest a general approach to constructing a new class of luminescent materials with tunable upconversion emissions by controlled manipulation of energy transfer within a nanoscopic region. © 2011 Macmillan Publishers Limited. All rights reserved.
SponsorsThe bulk of the work was supported by the Singapore Ministry of Education (No. MOE2010T2-1-083), the Singapore-MIT Alliance, and the Agency for Science, Technology and Research (No. IMRE/11-1C0110). Y.H. is grateful to KAUST Global Collaborative Research for the Academic Excellence Alliance (AEA) fund. H.Z. and X. C. acknowledge the financial support from the NSFC (Nos. 10974200 and 51002151) and the 863 programs of MOST (Nos. 2009AA03Z430 and 2011AA03A407). We thank T. Nguyen, Y. Liu and L. Tan for their help in sample characterization.