Tunable luminescent color and anti-thermal quenching of Dy3+ or/and Eu3+ doping in Sc2(WO4)3 phosphors for white light-emitting diode applications

Abstract

To address issues such as poor thermal stability and tunable luminescent colors of conventional phosphors for solid-state lighting applications, a series of Sc₂(WO₄)₃: Ln³⁺ (Ln = Dy or/and Eu) phosphors were synthesized via a high-temperature solid-state method, and their luminescent behaviors were investigated in detail. Under 350 nm excitation, the Sc₂(WO₄)₃:xDy³⁺ phosphor exhibits blue (487 nm), yellow (576 nm) and red (666 nm) emission peaks, and the optimal doping concentration of Dy³⁺ is 4 %. In the Sc₂(WO₄)₃:4 %Dy³⁺/yEu³⁺ phosphor, energy transfer is revealed through the analysis of the spectral overlap of Dy³⁺ and Eu³⁺, thereby achieving tunable luminescence from orange to red. Combined with the results of FT-IR and TG analyses, the Sc₂(WO₄)₃:4 %Dy³⁺/2 %Eu³⁺ phosphor exhibits non-hygroscopic properties. Furthermore, the Sc₂(WO₄)₃:4 %Dy³⁺ and Sc₂(WO₄)₃:4 %Dy³⁺/2 %Eu³⁺ phosphors exhibit excellent thermal stability (At 423 K, the intensity of the orange (576 nm) and red (612 nm) light both exceed 95 % of that of room temperature). In addition, the anti-thermal quenching mechanism is systematically investigated through temperature-dependent PL dynamics. This is attributed to combined action for the stabilized energy transfer process from Dy³⁺ to Eu³⁺ and the suppression of non-radiative transitions with the increase of temperature. These findings demonstrate that Sc₂(WO₄)₃:Dy³⁺/Eu³⁺ phosphors with excellent thermal stability and tunable luminescence can be used as potential applications in WLED fields.