A deep-red-emitting Bi3+/Mn4+-doped CaLi6La2Nb2O12 phosphor: Luminescence and energy transfer properties

Recently, much attention has been attracted on the optical properties based on the phosphors for LED light. A near Ultraviolet (n-UV) and blue chip activated phosphor of CaLi 6 La 2 Nb 2 O 12 :Bi 3+ , Mn 4+ is synthesized by a traditional SSR method. Phase purity and lattice structure of the crystal have been confirmed and investigated by XRD, Rietveld refinement, FE-SEM and TEM. The luminescence performances of the series phosphors are investigated by diffuse reflection spectra (DR), Raman scattering spectra, steady-state PL spectra and the measurement of lifetime., the CaLi 6 La 2 Nb 2 O 12 :Bi 3+ , Mn 4+ exhibits emission peaked at ∼466 and ∼711 nm Under excited at 312 nm. The Dq, B and C are calculated to estimate the nephelauxetic effect of Mn 4+ in [NbO 6 ] octahedral lattice. The coordinate shifting could be controllable through the energy transfer Bi 3+ →Mn 4+ , which can be verified by PL spectra and decay lifetimes. Finally, by coating the blend of red CaLi 6 La 2 Nb 2 O 12 :0.03Bi 3+ ,0.015 Mn 4+ and Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) phosphors onto the blue LED chip, a LED device with good performances ( x  = 0.36, y  = 0.36, CRI = 86.6, CCT =4220 K) can be achieved. Hence, CaLi 6 La 2 Nb 2 O 12 :Bi 3+ , Mn 4+ is a good material of red emission.