Synthesis and properties of carbon-coated metal nanomaterials modified Li2SrSiO4:Eu3+ phosphors

Li2SrSiO4:Eu3+ (LSSOE) phosphor is a new light-emitting material with outstanding optical properties. However, it exhibits poor thermal stability, which makes it susceptible to heat-induced degradation or color alteration, thus reducing Light-emitting diodes (LEDs) efficiency. To address this issue, we propose a novel phosphor modification method that involves synthesizing carbon-coated metal nanomaterials (Ag@C) and combining them with phosphor precursors to obtain Ag@C/LSSOE composites. The results demonstrated that with an Ag@C addition of 0.2%, the luminous intensity of the LSSOE phosphor increases considerably by 4 times compared to that of the original phosphor. The optical bandgap (Eg), quantum yield (QY), and fluorescence lifetime (τ) are 4.28 eV, 46.07%, and 2.01 ms, respectively. When the temperature was increased to 423 K, the luminous intensity of the modified phosphor reached 86% and 87% of its initial temperature (298 K) at emission wavelengths of 703 and 613 nm, respectively. The luminescence thermal quenching behavior of the phosphor samples was analyzed, and an activation energy (ΔE) of 0.398 eV was calculated. The addition of Ag@C considerably increases the luminous intensity of LSSOE phosphors and improves their thermal stability, rendering them ideal for high-power LED lamps emitting red light.