Fast synthesis of sub-10 nm β-NaYF4:Yb3+, Er3+@NaYF4 core-shell upconversion nanocrystals mediated by oleate ligands
- School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China)
Highlights: • Fast synthesize ultra-small β-NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} UCNCs with 0 min reaction or down to 5.3 nm. • Highly bright sub-10 nm β-NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} core-shell NCs were obtained. • OA{sup −} ligands cannot only promote the α-to-β phase transition, but also inhibit the crystal growth. • OA{sup −} ligands manipulated phase transition and size evaluation is also applicable to other UCNCs. - Abstract: We developed a facile approach for the fast synthesis of ultrasmall and monodisperse β-NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanocrystals down to 5.3 nm with the assistant of oleate ligands, based on which the highly bright sub-10 nm β-NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+}@NaYF{sub 4} core-shell nanocrystals with three order of magnitude increased upconversion emission were successfully obtained by a seed-mediated growth method. The reaction time and temperature dependent experimental results implied that the introduciton of extra oleate ligands can both promote the α-to-β phase transition and impeded the crystal growth of NaYF{sub 4}, which is due to the oleate ligand induced orderly arrangement of Y{sup 3+} and capping effect, respectively. It is expected that the oleate ligands mediated phase transition and size evaluation, demonstrated here in NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} NCs, is also applicable to other lanthanide-doped upconversion nanocrystals.
- OSTI ID:
- 22805138
- Journal Information:
- Materials Research Bulletin, Vol. 103; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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