Luminescence enhancement of Cd2V2O7:Re3+ (Re = Pr, Sm) red phosphors through Li+ ions charge compensation

Novel Cd2V2O7:Re3+, Li+ (Re = Pr, Sm) red phosphors were synthesized using a high-temperature solid state reaction, where Li+ was utilized as a charge compensator for luminescence enhancement. X-ray diffraction indicated that all the as-prepared samples had Cd2V2O7 pure phase and their structures remained unchanged with Re3+ and Li+ doping. Emission spectra of Cd2V2O7:Pr3+ phosphors excited at 380 nm revealed an orange red emission with two apparent peaks at 580 nm and 620 nm, corresponding to the D-1(2)-> H-3(4) and P-3(0)-> H-3(6) electronic transitions of Pr3+. The emission spectra of Sm3+ doped Cd2V2O7 phosphors showed one strong peak at 607 nm and two weak peaks at 572 nm and 654 nm, attributed to (4)G(5/2)-> H-6(7/2), (4)G(5/2)-> H-6(5/2) and (4)G(5/2)-> H-6(9/2) transitions, respectively. Moreover, the luminescence intensities of Cd2V2O7:Re3+ (Re = Pr, Sm) samples were enhanced observably by Li+ ions doping with charge compensation effect. Overall, these findings suggested that Cd2V2O7:Re3+, Li (Re = Pr, Sm) red phosphors can be used as a promising red component in near ultraviolet excited white light-emitting diodes with improved performances.