Thermally enhanced luminescence of down-conversion NaScMo2O8:Eu3+ phosphor for white LEDs

Abstract

The thermal quenching effect of phosphors imposed significant limitations on the applications of luminescent materials in high-temperature environments, which can lead to device performance degradation or even system failure. Currently, there was a lack of red phosphors that demonstrate high luminous efficiency, excellent stability, and high color purity, making them suitable for white light-emitting diodes (LEDs). Herein, a strategy to enhance luminescence at elevated temperatures was achieved by synthesizing Eu³⁺-doped monoclinic NaScMo₂O₈ phosphors, whose structural, morphological, thermal, and optical properties were characterized by XRD, SEM, TG, and PL spectroscopy. A comprehensive investigation of the optical properties revealed a significant increase in luminescence intensity with high Eu³⁺ concentrations. At a doping concentration of 3 mol%, the phosphor exhibited the strongest electric dipole transition (⁵D₀-⁷F₂) with a maximum emission peak at 614 nm. Between 30 °C and 270 °C, the red characteristic emissions of Eu³⁺ gradually intensified with rising temperature, reaching up to 8 times the intensity at room temperature, while maintaining consistent fluorescence characteristics. These findings highlighted its potential application in white LEDs.