Experimental demonstration of the relationship between the OH− content and photoluminescence in Tb-doped YPO4∙2H2O

Tb-doped YPO4∙2H2O was synthesized via a simple wet-chemical route. Both the crystallinity of samples and the concentration of OH− adsorbed at the surface were experimentally controlled by adjusting the reaction time. An abnormal phenomenon that photoluminescence efficiency decreases with the increase of crystallinity demonstrates enormously adverse effect of OH− on photoluminescence, especially, as the OH− content reaches a critical value, the luminescent efficiency decreases more drastically. This strong dependence of photoluminescence on the OH− content indicates that to control the OH− content in a limited range or to reduce the OH− effect as much as possible is an efficient way to improve photoluminescence efficiency.