Abstract
KGaA, Weinheim One major challenge in upconversion research is to develop new materials and structures to expand the emission spectrum. Herein, a heterogeneous core−shell−shell nanostructure of NaYbF4:Gd/Tm@NaGdF4@CaF2:Ce is developed to realize efficient photon upconversion in Ce3+ ions through a Gd-mediated energy migration process. The design takes advantage of CaF2 host that reduces the 4f–5d excitation frequency of Ce3+ to match the emission line of Gd3+. Meanwhile, CaF2 is isostructural with NaGdF4 and can form a continuous crystalline lattice with the core layer. As a result, effective Yb3+ → Tm3+ → Gd3+ → Ce3+ energy transfer can be established in a single nanoparticle. This effect enables efficient ultraviolet emission of Ce3+ following near infrared excitation into the core layer. The Ce3+ upconversion emission achieved in the core−shell−shell nanoparticles features broad bandwidth and long lifetime, which offers exciting opportunities of realizing tunable lasing emissions in the ultraviolet spectral region.
Original language | English |
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Article number | 1701479 |
Journal | Small |
Volume | 13 |
Issue number | 43 |
DOIs | |
Publication status | Published - 20 Nov 2017 |
Keywords
- cerium upconversion
- core−shell nanoparticles
- energy migration
- tunable ultraviolet lasing
ASJC Scopus subject areas
- Biotechnology
- Biomaterials
- Engineering (miscellaneous)