Perovskite La2LiRO6:Mn4+ (R = Nb, Ta, Sb) phosphors: Synthesis and luminescence properties

LiLa2RO6:Mn4+ (R = Nb, Ta, and Sb) phosphors are successfully synthesized via high-temperature solid-state reaction method in air, which are confirmed by their X-ray diffraction patterns and luminescence properties. Excitation spectra of LiLa2RO6:Mn4+ (R = Nb, Ta, and Sb) phosphors cover the region from 220 nm to 560 nm. LiLa2RO6:Mn4+ (R = Nb, Ta, and Sb) phosphors emit deep red light and their emission spectra exhibit a broadband ranging from 650 to 780 nm with maximum emission peak at ∼714, 712, 710 nm, respectively. Their emission and excitation spectral peaks have a blue shift in order of Nb, Ta, and Sb because of the influence of host crystal field. The optimal Mn4+ concentration in LiLa2RO6:Mn4+ (R = Nb, Ta, and Sb) phosphors is ∼0.4 mol%. The flurescence lifetimes of LiLa2RO6:0.4%Mn4+ (R = Nb, Ta, and Sb) phosphors are ∼1.90, 1.67, and 2.03 ms, respectively. The luminous mechanism is explained by the Tanabe-Sugano energy level diagram of Mn4+ ion. The paper content is helpful for the basic research on luminescence properties of Mn4+ ion.