Dual-strategy of Eu2+ sensitization and Ca2+ substitution improves the luminescence properties of phosphor Sr2La8(SiO4)6O2:Eu

A series of novel orange-red phosphors Sr1.9-xCaxLa8(SiO4)6O2:0.1Eu(2+,3+) (0≤ x ≤ 1.9, Δx=0.3) were successfully prepared via high-temperature solid-state reaction. The crystal structure, fluorescence spectral characteristics, thermal stability, fluorescence lifetime, morphological characteristics and Eu valence state of the phosphor were systematically studied. The successful introduction of Eu2+ broadened the excitation spectrum of Sr1.9-xCaxLa8(SiO4)6O2:0.1Eu(2+,3+) by more than 100 nm and increased the fluorescence intensity by 200%, realizing the energy transfer between Eu2+ and Eu3+. The fluorescence intensity of Sr0.4Ca1.5La8(SiO4)6O2:0.1Eu(2+,3+) is increased by 551% through the Ca2+ substitution strategy, and the Ca2+ enters the matrix lattice, which promotes the reduction of Eu3+ to Eu2+ and improves the energy transfer efficiency. The emission intensity of Sr0.4Ca1.5La8(SiO4)6O2:0.1Eu(2+,3+) remained at 70.29% at 418 K. The color coordinates of Sr1.9-xCaxLa8(SO4)6O2:0.1Eu(2+,3+) are all located in the orange-red region, the color coordinates are about (0.59, 0.40), and the color temperature are about 2100 K. Therefore, the excellent optical properties of this series of phosphors make them have potential practical value in the LED field.