Chemical unit cosubstitution and tuning of photoluminescence in Eu2+ doped Ca1.65-xScxSr0.35Si1-xGaxO4 phosphors

The design scheme of chemical cosubstitution of [Sc3+- Ga3+] for [Ca2+-Si4+] pairs in the Eu2+ doped Ca1.65Sr0.35SiO4(CSSO) phosphors has been put into practice to investigate their structure and optical properties systematically. X-ray diffraction patterns and Rietveld refinements were used to demonstrate the successful incorporation of Sc3+/Ga3+ into CSSO: Eu2+. All phosphors exhibit the general orthorhombic structure with space group of P21CN. Eu2+ activated CSSO phosphors exhibit strong absorption in the range of 260-450 nm and a green emission peak centered at about 506 nm. Under the excitation of 365 nm, the peak position for the Sc-Ga substitutions can be shifted from 506 to 524 nm, which is expected to obtain single-phased phosphors excited by UV-LEDs. The cosubstitution of [Sc3+- Ga3+] for [Ca2+-Si4+] can improve the thermal stability of the materials. This research is in favor of enriching colors of Eu2+ doped CSSO phosphors.