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Preparation and upconversion luminescence characterization of 12CaO·7Al 2 O 3 :Ho 3+ /Yb 3+ polycrystals
Author(s) -
Qu Yunfei,
Wang Rui,
Liu Liang,
Sun Jinchao,
Xing Lili,
Tao Ye,
Wu Xiaohong
Publication year - 2013
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201300112
Subject(s) - photon upconversion , luminescence , analytical chemistry (journal) , materials science , excited state , ion , green light , fluorescence , emission spectrum , emission intensity , raman spectroscopy , excitation , spectral line , chemistry , atomic physics , optics , optoelectronics , physics , blue light , organic chemistry , chromatography , astronomy , quantum mechanics
The effect of Yb 3+ concentration on the fluorescence of 12CaO·7 Al 2 O 3 :Ho 3+ /Yb 3+ polycrystals is investigated. The Raman spectra of pure C12A7 under 633‐nm excitation show that the highest photon energy is 787.267 cm −1 , which is not much bigger than general fluorides, so it can realize high efficiency upconversion. The upconversion emission spectra suggest that the green upconversion emission centered at 548 nm and the red upconversion emission at 662 nm correspond to the 5 F 4 / 5 S 2 → 5 I 8 and 5 F 5 → 5 I 8 transition of Ho 3+ ions, respectively. The intensity of the upconversion luminescence and the ratio of red to green are changed with Yb 3+ ion concentration. The pump dependence and luminescence decay dynamics spectra show the green and red upconversion emissions are populated by a two‐photon process, and the upconversion mechanisms are analyzed. The relative luminous efficiencies of green and red emissions are 2.035% and 0.7%, respectively. The normalized efficiency obtained for green emission of Ho 3+ at RT when the sample is excited by 980‐nm light with an absorbed intensity of 7.5 W/cm 2 is 0.27 cm 2 /W. This result is comparable to the values obtained in YF 3 for the Yb 3+ , Er 3+ green emission. The C12A7 with upconversion red and green light will be a promising luminous material.