Experimental demonstration of the relationship between the OH^- content and photoluminescence in Tb-doped YPO₄ṡ2H₂O

Tb-doped YPO₄ṡ2H₂O 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.