Effect of do** Sr²⁺ on luminescence and abnormal thermal quenching behavior of silicate solid-solution green phosphor Ba₉Lu₂Si₆O₂₄:Eu²⁺

Abstract

A novel Eu²⁺ ions doped silicate solid-solution green phosphors, (Ba_1−ySr_y)₉Lu₂Si₆O₂₄:0.14Eu²⁺ (0 ≤ y ≤ 0.25), have been successfully prepared by conventional sintering method. The Rietveld refinement result was taken to determine the pure phase of (Ba_1−ySr_y)₉Lu₂Si₆O₂₄:0.14Eu²⁺ (0 ≤ y ≤ 0.25). The characteristic optical properties, especially the thermal quenching properties were studied. The excitation spectra of (Ba_1−ySr_y)₉Lu₂Si₆O₂₄:0.14Eu²⁺ span from 350 to 460 nm. When the Sr²⁺ contents increased, the dominate emission peak was found to red shift from 503 to 525 nm under n-UV excitation. The emission intensity of (Ba_0.75Sr_0.25)₉Lu₂Si₆O₂₄:0.14Eu²⁺ can reach 90% compared with the emission intensity of commercial phosphor LMS520B. Moreover, when the do** concentration of Sr²⁺ reaches 25%, the phosphor can obtain a smaller thermal quenching (TQ), which still kept 85% of the initial emission intensity when the temperature increased to 150 °C. The reason why the temperature stability increased along with the increasing Sr²⁺ ions was illustrated expressly through the schematic diagram and the activation energy calculated by Arrhenius equation. Moreover, the chromaticity index shifted from (0.2157, 0.4165) to (0.2812, 0.5744), and the color purity of (Ba_1−ySr_y)₉Lu₂Si₆O₂₄:0.14Eu²⁺ increased from 32.36% to 56.82% with the concentration of Sr²⁺ changing from y = 0 to y = 0.25.