Synthesis and Luminescence Characterization of Novel Red-Emitting Phosphors Based on Eu3+-Activated K2Sr(MoO4)2 Molybdates for w-LEDs.

Abstract

In this work, trivalent europium (Eu³⁺) ion activated K₂Sr(MoO₄)₂ red phosphors have been synthesized through high-temperature solid-state reaction method at 750 ℃. Detailed analysis was conducted on the phase purity, morphology, and luminescence properties of the synthesized phosphors. X-ray diffraction (XRD) confirmed the successful formation of K₂Sr(MoO₄)₂:Eu³⁺ phosphors with pure phase with space group С_2/c. The photoluminescence (PL) spectroscopy was used to record the excitation and emission spectrum of Eu³⁺ activated K₂Sr(MoO₄)₂ phosphor. Under the excitation of 280 nm, the resultant samples exhibited the characteristic emissions of Eu³⁺ ions corresponding to the ⁵D₀→⁷F_J transitions. The optimal doping concentration of Eu³⁺ ions was determined to be 35 mol%. Concentration quenching mechanism was identified as the interaction of near-neighbor ions. The chromaticity coordinates of K₂Sr(MoO₄)₂:35 mol%Eu³⁺ were (0.659, 0.340) with a corresponding high color purity of 99.8%. The prepared K₂Sr(MoO₄)₂:35 mol%Eu³⁺ phosphor had good thermal stability with temperature quenching temperature (T_0.5 > 420 K) and high activation energy (E_a = 0.267 eV). The exhaustive findings from this study form the basis for advocating the application of these phosphors in light-emitting devices.