Fast synthesis of red Li₃BaSrLn₃(WO₄)₈:Eu³⁺ phosphors for white LEDs under near-UV excitation by a microwave-assisted solid state reaction method and photoluminescence studies

Red Li₃BaSrLa₃(WO₄)₈:Eu³⁺ phosphors have been successfully synthesized by a rapid microwave-assisted solid state method. The sintering time for the optimal phosphor can be limited to only 10 minutes at 900 °C. Upon near-ultra-violet (NUV) excitation, strong red emission can be found in 90% Eu³⁺ doped tungstate compounds. This phosphor exhibits impressive thermal stability, and the purity of red emission Li₃BaSrLa₃(WO₄)₈:Eu³⁺ in high Eu³⁺ doping concentrations can achieve the coordinate values (x = 0.670, y = 0.330), indicating high red color purity. The corresponding quantum yield (QY) is measured (28.36 ± 0.09%). Photoluminescence and kinetic studies showed no obvious effects due to the concentration quenching effect, cross relaxation and non-radiative energy transfer. Li₃BaSrLa₃(WO₄)₈:Eu³⁺ can be synthesized using a simple and quick method and the comprehensive photophysical studies of the novel phosphor (Li₃BaSrLa₃(WO₄)₈:Eu³⁺) have been done and the potential as a practical phosphor for NUV-excited white LEDs (WLEDs) has been shown.