LUMINESCENCE ENHANCEMENT OF SKY-BLUE ZnS:Tm PHOSPHOR BY PROMOTER DOPING

摘要

Luminescence of ZnS:Tm phosphor was enhanced by the addition of KC1 promoter. High synthesis temperature and TmF_3 concentration promoted the substitution of Tm~3+ ions for Zn~2+ ions, leading to the growth of Tm_2S_3 phase. The ionic defects were increased with the increase of Tm~3+ concentration, which influenced the luminescence characteristics of phosphor when the energy transferred to the defects was not effectively cascaded to the luminescence center. KCl promoter doping facilitated the growth of hexagonal phase and decreased the phase transformation temperature of ZnS. The emission pattern and peaks of the ZnS:Tm,KCl phosphor were similar to those of ZnS:Tm phosphor. This shows that the variation in the ligand field of Tm~3+ because of KC1 doping was insignificant. The luminescence center concentration, the excitation energy absorption, the effective energy transfer, and the charge balance were improved by the addition of KC1 promoter. Consequently, the luminescence of phosphor was effectively enhanced.