Preparation and photoluminescence properties of high thermal stability Sr3Ga2Sn1.5Si2.5O14:Eu3+ red phosphors for high-power light-emitting diodes application

Abstract

A series of Sr₃Ga₂Sn_1·5Si_2·5O₁₄:xEu³⁺ (SGSSO:xEu³⁺) phosphors with excellent thermal stability were prepared by the solid-state reaction method. The phase and luminescence properties of the sample were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy, and photoluminescence (PL) spectra. Under the excitation of 395 nm, the SGSSO:Eu³⁺ phosphor exhibits strong red emission at 618 nm, which is attributed to the ⁵D₀ → ⁷F₂ transition of the Eu³⁺ ions. When monitoring the 618 nm emission peak, the excitation spectrum contains several excitation peaks with a maximum value of 395 nm, which is well matched with the commercial violet LED chips. In addition, the emission spectra of SGSSO:Eu³⁺ at different temperatures have also been studied. Pleasantly, the luminous intensity of the SGSSO:Eu³⁺ sample at 150 °C still maintains 80.2% of that at room temperature, demonstrating its good thermal stability and application potential in high-power LEDs. The mechanism for the high thermal stability of the as-prepared phosphor was also discussed. Moreover, the photoluminescence quantum yield of the optimized SGSSO:0.06Eu³⁺ phosphor can reach 62.7%. Finally, a warm white LED device with high color rendering index and low color temperature was prepared using the prepared SGSSO:Eu³⁺ phosphor as a red component, verifying the application potential of SGSSO:0.06Eu³⁺ in LEDs.