Effect of different temperatures to remove reduction gas on the photoluminescence properties of Eu‐doped Li₂(Ba_1‐xSr_x)SiO₄ phosphors

Abstract

In this study, Eu‐doped Li2(Ba1‐xSrx)SiO4 powders (x = 0, 0.2, 0.4, and 0.6) were synthesized at 850°C in a reduction atmosphere (5% H2 + 95% N2) for a duration of 1 h using a solid‐state reaction method. The reduction atmosphere was infused as the synthesis temperature reached 850°C, and was removed as the temperature dropped to 800–500°C. Li2(Ba1‐xSrx)SiO4 (or Li2BaSiO4), (Ba,Sr)2SiO4 (or BaSiO4), and Li4SiO4 phases co‐existed in the synthesized Eu‐doped Li2(Ba1‐xSrx)SiO4 powders. A new finding was that the reduction atmosphere removing (RAR) temperature of the Li2(Ba1‐xSrx)SiO4 phosphors had a large effect on their photoluminescence excitation (PLE) and PL properties. Except for the 800°C‐RAR‐treated Li2BaSiO4 phosphor, PLE spectra of all other Li2(Ba1‐xSrx)SiO4 phosphors had one broad emission band with two emission peaks centred at ~242 and ~283 nm; these PL spectra had one broad emission band with one emission peak centred at 502–514 nm. We showed that the 800°C‐RAR‐treated Li2BaSiO4 phosphor emitted a red light and all other Li2(Ba1‐xSrx)SiO4 phosphors emitted a green light. Reasons for these results are discussed thoroughly.