The influence of site occupancy of Li+, including substitutional and interstitial sites, on the up-conversion emissions of Er3+ doped Y3Al5O12 powders was reported. The intensity of green emission increases slightly when the Li+ occupies substitutional site, but when the Li+ enters into interstitial site it enhances drastically accompanied with a change of emission spectra. These phenomena originate from the increase, induced by interstitial Li+, in the lifetime of 4I11/2 level, the ratio of radiation rate in green emission and the absorptivity at 980nm.

Enhancement of Up-Conversion Emission in Y3Al5O12:Er3+ Induced by Li+ Doping at Interstitial Sites. M.Yang, Y.Sui, S.Wang, X.Wang, Y.Sheng, Z.Zhang, T.Lü, W.Liu: Chemical Physics Letters, 2010, 492[1-3], 40-3