Synthesis and photoluminescence properties of Sr3(PO4)2:Re3+, Li+ (Re = Eu, Sm) red phosphors for white light-emitting diodes

Sr-3(PO4)(2):Re3+, Li+ (Re = Eu, Sm) red phosphors were prepared via a high temperature solid state reaction, and their structure and luminescence properties were investigated. X-ray diffraction patterns indicate that the phase of as-prepared samples is in good agreement with standard Sr-3(PO4)(2) structure. Under 395 nm excitation, the emission of Sr-3(PO4)(2):Eu3+ consists of a strong peak centered at 622 nm and two weak peaks centered at 598 nm and 660 nm, which correspond to D-5(0)-> F-7(2), D-5(0)-> F-7(1) and D-5(0)-> F-7(3) transitions, respectively. Also, the emission spectrum of Sr-3(PO4)(2):Sm3+ shows three main peaks at 568 nm, 603 nm and 651 nm, which are attributed to (4)G(5/2) -> H-6(1/2) (I = 5, 7, 9) transitions of Sm3+. Furthermore, luminescence properties of Sr-3(PO4)(2):Re3+, Li+ (Re = Eu, Sm) samples are enhanced significantly by Li+ ions doping as charge compensator. Results indicate that as-prepared Sr-3(PO4)(2):Re3+, Li+ (Re = Eu, Sm) could be the potential red phosphors used in white light-emitting diodes.