title: Site Occupancies, Luminescence, and Thermometric Properties of LiY9(SiO4)6O2:Ce3+Phosphors.
abstract: In this work, we report the tunable emission properties of Ce3+in an apatite-type LiY9(SiO4)6O2compound via adjusting the doping concentration or temperature. The occupancies of Ce3+ions at two different sites (Wyckoff 6h and 4f sites) in LiY9(SiO4)6O2have been determined by Rietveld refinements. Two kinds of Ce3+f-d transitions have been studied in detail and then assigned to certain sites. The effects of temperature and doping concentration on Ce3+luminescence properties have been systematically investigated. It is found that the Ce3+ions prefer occupying Wyckoff 6h sites and the energy transfer between Ce3+at two sites becomes more efficient with an increase in doping concentration. In addition, the charge-transfer vibronic exciton (CTVE) induced by the existence of free oxygen ion plays an important role in the thermal quenching of Ce3+at 6h sites. Because of the tunable emissions from cyan to blue with increasing temperature, the phosphors LiY9(SiO4)6O2:Ce3+are endowed with possible thermometric applications.
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Weijie
authors.initials: W
authors.lastname: Zhou
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Pan
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Dejian
authors.initials: D
authors.lastname: Hou
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100039, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100039, People's Republic of China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tao
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Liang