High-Brightness LaPO4:Ce3+, Tb3+ Nanophosphors: Reductive Hydrothermal Synthesis and Photoluminescent Properties

This paper definitely reveals that LaPO4:Ce3+, Tb3+ (LAP) nanophosphors prepared by normal hydrothermal method suffer significant loss of luminescence due to the oxidation of Ce3+–Ce4+ at hydrothermal stage. To effectively protect Ce3+ from oxidation, a reductive hydrothermal process using hydrazine hydrate as a protecting agent is proposed to synthesize LAP nanophosphors with different Ce3+ and Tb3+ concentrations, which exhibited much stronger green photoluminescence (PL) and longer lifetime than the products prepared by normal hydrothermal method. Furthermore, the high‐brightness LAP nanophosphors exhibited high‐quenching concentration of Tb3+; the La0.4Ce0.4Tb0.2PO4 nanophosphor showed almost the same PL intensity as that of the commercially used La0.7Ce0.2Tb0.1PO4 bulk powder.