| Popis: |
Ce3+ ions were introduced into the Er3+/Yb3+ -codoped TeO2-WO3-ZnO glasses, and the effect of Ce3+ on the emission properties at 1.5 mu m band and the upconversion luminescence of Er3+ in the glasses was investigated. With the increasing of Ce3+ concentration, the emission intensity of Er3+ at 1.5 mu m band increases firstly, and then decreases. The optimal doping concentration of Ce3+ is about 2.07 x 10(20)/cm(3). As for the Er3+ emission at 1.5-mu m band, the fluorescence lifetime decreases a little from 3.4ms to 3.0ms, while the full width at half maximum (FWHM) hardly changes with the increase of Cc 3+ concentration. Due to the effective cross relaxation between Ce3+ and Er3+ : Er3+ (I-4(11/2)) + Ce3+ (F-2(5/2)) -> Er3+ (I-4(13/2)) + Ce3+ (F-2(7/2)), the upconversion emission intensity of Er3+ is reduced greatly. But when Ce3+ -doping concentration is too high, the other cross relaxation between Ce3+ and Er3+ : Er3+ (4I(13/2)) + Ce3+ (F-2(5/2)) -> Er3+ (I-4(15/2)) + Ce3+ (F-2(7/2)) happens, which depopulates the I-4(13/2) level of Er3+ and results in the decrease of the emission intensity and fluorescence lifetime of Er3+ at 1.5 mu m band. |
