Ce³⁺-doped silicate-based down-conversion phosphors: investigation on synthesis, structure and photoluminescence properties

Two types of Ce³⁺-doped silicate-based phosphors with different silicon-to-oxygen (Si-to-O) ratio have been synthesized by high-temperature solid state reaction and investigated systematically the influence of Si-to-O ratio on host structures and photoluminescence properties of Ce³⁺-doped phosphors. Due to diverse Si-to-O ratio in two silicate-based hosts, Ce³⁺ shows different site occupancies and luminescence behaviors, since the host structure has been changed by introducing O atom. In the Sr_2+x−yMgSi₂O_7+x:yCe³⁺ (x = 0 or 1, y = 0.005–0.09) phosphors system, the excitation wavelength both showed at UV region, the emission wavelength changed from violet to blue light region with increasing the value of x (x = 0 or 1), which have been analyzed by the crystal-field effect of Ce³⁺. The PL results indicate that Sr_2−0.01MgSi₂O₇:0.01Ce³⁺ phosphors (x = 0) exhibits a deep-blue emission with peak at 405 nm, while the peak of Sr_3−0.01MgSi₂O₈:0.01Ce³⁺ phosphors (x = 1) moves to 395 nm from the increased ratio of Si-to-O. Besides, the optimal concentration of doping Ce³⁺ are both at 0.01 in two kinds of silicate-based phosphors which display stable and good luminescent performance. Our work provides a novel thinking of regulating photoluminescence properties by manipulating Si-to-O ratio in silicates and a valuable example for the emission characteristics of Ce³⁺ activators in silicate-based phosphor hosts.