Synthesis and Optical Properties of KYF4/Yb, Er Nanocrystals, and their Surface Modification with Undoped KYF4
Autor(en): | Schaefer, Helmut Ptacek, Pavel Zerzouf, Otmane Haase, Markus |
Stichwörter: | Chemistry; Chemistry, Multidisciplinary; Chemistry, Physical; DEPENDENCE; EMISSION; FLUORESCENCE; FLUORITE STRUCTURE; HEXAGONAL-PHASE; LANTHANIDE; LASER; Materials Science; Materials Science, Multidisciplinary; Nanoscience & Nanotechnology; Physics; Physics, Applied; Physics, Condensed Matter; Science & Technology - Other Topics; SPECTROSCOPY; UP-CONVERSION LUMINESCENCE; YB-KYF4 | Erscheinungsdatum: | 2008 | Herausgeber: | WILEY-V C H VERLAG GMBH | Journal: | ADVANCED FUNCTIONAL MATERIALS | Volumen: | 18 | Ausgabe: | 19 | Startseite: | 2913 | Seitenende: | 2918 | Zusammenfassung: | KYF4/Yb3+, Er3+ nanocrystals with a mean diameter of approximately 13 nm were synthesized at 200 degrees C in the high boiling organic solvent N-(2-hydroxyethyl)ethylenediamine (HEEDA). The particles crystallize in the cubic phase known from alpha-NaYF4 and form transparent colloidal solutions in tetraethylene glycol (TEG) or propanol. Solutions containing I wt % of the nanocrystals in TEG display visible upconversion emission upon continuous wave (CW) excitation at 978 nm. Growing undoped KYF4 on the surface of the KYF4/Yb3+, Er3+ nanocrystals increases the upconversion efficiency by more than a factor of 20. The XRD data of these particles, display a slight increase in the mean particle size from 13 to 15.5 nm, indicating that only a part of the subsequently added KYF4 shell material is deposited onto the particle surface. Nevertheless the performed surface modification obviously leads to core/shell structured particles. |
ISSN: | 1616301X | DOI: | 10.1002/adfm.200800368 |
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geprüft am 12.05.2024