Er3+ and Li+ codoped Y3Al5O12(YAG) powders were prepared for a systematic investigation of their upconversion emissions.X-ray diffraction(XRD),upconversion emission spectra,pump power dependence,FT-IR spectra and decay time were studied to characterize the samples.With Li+ doping,the upconversion emission intensity of Er3+ doped YAG powders was obviously enhanced,accompanied with an increase in the ratio of green to red intensity.The enhancement of emission intensity could be attributed to two mechanisms:one was the distortion of local crystal field around Er3+,and the other was the decrease in the amount of CO32-and OH-groups.Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er3+/Li+ powders.
