Luminescence properties of single-phase SrMg2La2W2O12:Tb3+, Sm3+, Tm3+ phosphor for multicolor- and white light-emitting LEDs

In the present work, multicolor-emitting phosphors SrMg2La2W2O12:RE3+ (RE = Tb, Sm, Tm) prepared by the solid-state reaction method were reported as interesting down-conversion luminescent materials for white light-emitting diodes and displays. The structural and bonding information understood by XRD and FTIR revealed their corresponding orthorhombic structure and vibrational energies, respectively. The excitation and emission spectra of singly Tb3+, Sm3+, and Tm3+ doped SrMg2La2W2O12 phosphors indicate that these phosphors can be effectively excited by UV light and emit green, orange-red, and blue light respectively. The photoluminescence, decay times, Commission Internationale de L'Eclairage (CIE) chromaticity coordinates, and correlated color temperatures (T-cct) are determined for various concentrations of the activators Tb3+, Sm3+, and Tm3+ in a SrMg2La2W2O12 host. The results indicate that when tri-doped SrMg2La2W2O12 phosphor is excited with a ligand-to-metal charge transfer (LMCT), it emits green, orange-red, and blue colors simultaneously and can be tunable to white light. An efficient energy transfer was observed among the rare earth ions and was examined through decay curve analysis. The investigation suggests that SrMg2La2W2O12:RE3+ (RE = Tb, Sm, Tm) were potential candidates for application in the development of LEDs and displays.