Effects of different dopants and synthesizing temperatures on the microstructures and photoluminescence properties of Sr_1.4Ba_0.6SiO₄-based phosphors

Rare-earth ions can be used to design a virtually unlimited number of new luminescent materials because of their special energy level transitions in different energy bands. In this study, Nd₂O₃, Eu₂O₃ and Sm₂O₃ were used as dopants to produce commercial Sr_1.4Ba_0.6SiO₄:Nd, Sr_1.4Ba_0.6SiO₄:Eu, and Sr_1.4Ba_0.6SiO₄:Sm phosphors by a solid-state reaction method. All the Sr_1.4Ba_0.6SiO₄-based phosphors were synthesized in the temperature range of 1000–1300 °C for 2 h. XRD patterns revealed that when different dopants and synthesizing temperatures were used, the Sr_1.4Ba_0.6SiO₄-based phosphors had different physical and luminescent properties. The SiO₂ phase in Sr_1.4Ba_0.6SiO₄:Nd powder was observed when the synthesizing temperature was 1000 °C but was absent if the synthesizing temperature was higher. There were no raw material or secondary phase residuals in the Sr_1.4Ba_0.6SiO₄:Eu powder, even when the synthesizing temperature was 1000 °C. In the case of Sr_1.4Ba_0.6SiO₄:Sm powder, secondary or unknown phases were still observed if the synthesizing temperature was lower than 1300 °C. When the temperature was increased from 1000 to 1300 °C, the 2θ value and the full width at half maximum value of the (103) plane underwent no apparent change in the Sr_1.4Ba_0.6SiO₄:Nd and Sr_1.4Ba_0.6SiO₄:Eu powders. This study also thoroughly investigated the effects of different dopants and synthesizing temperatures on the luminescent properties of Sr_1.4Ba_0.6SiO₄-based phosphors.