Open AccessIntense ultraviolet upconversion luminescence from hexagonal NaYF_4:Yb^3+/Tm^3+ microcrystals
Author(s) -
Guofeng Wang,
Weiping Qin,
Lili Wang,
Guodong Wei,
Peifen Zhu,
Ryongjin Kim
Publication year - 2008
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.011907
Subject(s) - photon upconversion , excitation , materials science , ion , luminescence , emission intensity , ultraviolet , optics , analytical chemistry (journal) , molecular physics , atomic physics , optoelectronics , chemistry , physics , organic chemistry , chromatography , quantum mechanics
Under 980 nm excitation, unusual 3P2-->3H6 (approximately 264 nm) and 3P2-->3F4 (approximately 309 nm) emissions from Tm3+ ions were observed in hexagonal NaYF4:Yb3+ (20%)/Tm3+ (1.5%) microcrystals. In comparison with the strong emissions from 1D2 and 1I6, the emissions from 1G4 and 3H4 almost vanished due to the efficient cross-relaxation of 1G4 + 3H4-->3F4 + 1D2(Tm3+). Double logarithmic plots of the upconversion emission intensity versus the excitation power are neither straight lines nor typical saturation curves. Theoretical analysis indicated that the complicated dependent relationships were mainly caused by phonon-assisted energy transfers and nonradiative relaxation.