摘要
The visible upconversion and near-infrared luminescence of Er3＋ ions in germanate glass ceramics containing GaF2 nanocrystals are investigated. The nanocrystals are characterized by x-ray diffraction （XRD） and transmission electron microscopy, showing their mean sizes less than 20hm. High transmittance of the glass ceramics is displayed by absorption spectra. The upconversion luminescence intensity in the glass ceramics increases significantly with increasing temperature. Both the shifts of the XRD peaks and the Stark-split shown in the luminescence spectra indicate the entrance of the Er3＋ ions into the CaF2 nanocrystals, which is confirmed by a Judd-Ofelt analysis. Possible mechanisms of the upconversion luminescence are analyzed.
The visible upconversion and near-infrared luminescence of Er3＋ ions in germanate glass ceramics containing GaF2 nanocrystals are investigated. The nanocrystals are characterized by x-ray diffraction （XRD） and transmission electron microscopy, showing their mean sizes less than 20hm. High transmittance of the glass ceramics is displayed by absorption spectra. The upconversion luminescence intensity in the glass ceramics increases significantly with increasing temperature. Both the shifts of the XRD peaks and the Stark-split shown in the luminescence spectra indicate the entrance of the Er3＋ ions into the CaF2 nanocrystals, which is confirmed by a Judd-Ofelt analysis. Possible mechanisms of the upconversion luminescence are analyzed.
基金
Supported by the National Natural Science Foundation of China under Grant No 50802103.
