Synthesis and luminescence properties of La7Ta3W4O30:Dy3+ yellow-emitting phosphor for solid-state lighting applications

Abstract

This work was the first to synthesize the yellow-emitting phosphor La7Ta3W4O30:Dy3+ via a high-temperature solid reaction. The structure of La7Ta3W4O30:Dy3+ is trigonal crystalline pertaining to the R-3 (No.148) space group. Under 388-nm excitation, the photoluminescence spectrum of the La7Ta3W4O30:0.10Dy3+ sample exhibited four sharp peaks, which were attributed to 4F9/2–6H15/2 (480 nm), 4F9/2–6H13/2 (573 nm), 4F9/2–6H11/2 (658 nm), and 4F9/2–6H9/2 (753 nm) transitions. The optimal doping content of Dy3+ was 10 mol%, and the critical transfer distance (Rc) of the energy transfer between Dy3+ reached 22 A. The concentration quenching mechanism involved the dipole–dipole interaction. The quenching temperature was higher than 450 K. The fabricated white light-emitting diode (W-LED) possesses a high color rendering index (Ra = 88), good correlated color temperature (5710 K), and chromaticity coordinates (0.328, 0.335) that are close to those of standard white light (0.333, 0.333). Therefore, this prepared phosphor is a potential candidate for W-LED applications.