Preparation and properties of Tm3+/Eu3+/Tb3+ co-doped La2(PO4)1.5(BO3)0.5 phosphors

The synthesis of Tm3+ mono-doped, Tm3+-Eu3+ double-doped, and Tm3+-Eu3+-Tb3+ triple-doped La-2(PO4)(1.5)(BO3)(0.5) phosphors was achieved using the hydrothermal process. Subsequently, their crystal phase, photoluminescent properties, quantum yield, and thermal stability were analyzed. XRD analysis confirmed that all the synthesized phosphors belong to the hexagonal crystal system. FT-IR analysis confirmed the coexistence of both PO43- and BO33- ions in the phosphor. The chemical elemental composition of the phosphor was determined by XPS. The fluorescence lifetime test revealed the Tm3+ -> Eu3+ energy transfer process in the Tm3+-Eu3+ double-doped phosphor. It also indicated the presence of both Tm3+ -> Eu3+ and Tm3+ -> Tb3+ energy transfer processes in the Tm3+-Eu3+-Tb3+ triple-doped phosphor. The La-1.93(PO4)(1.5)(BO3)(0.5): 0.03 Tm3+, 0.03Eu(3+), 0.01 Tb3+ phosphor achieves white light emission with a Correlated Color Temperature of 5165 K, CIE of (0.3395, 0.3295), and a color purity of 1.91 %. It has a quantum yield of 36.16 % and a Delta E value of up to 0.20 eV, indicating high quantum yield and thermal stability.