La6Ba4Si6O24F2:Sm3+ novel red-emitting phosphors: Synthesis, photoluminescence and theoretical calculations

A series of novel red-emitting La6Ba4Si6O24F2:Sm3+ (LBSOF:Sm3+) phosphors was synthesized by a conventional solid state reaction. The crystal structure and atomic coordinates of La6Ba4Si6O24F2:Sm3+ were characterized by Rietveld refinement. Luminescent properties of as-synthesized La6Ba4Si6O24F2:Sm3+ phosphors are studied by measuring the photoluminescence/photoluminescence excitation (PL/PLE) spectra, decay life time, and thermal quenching. The results indicate that composition-optimized LBSO:1%Sm exhibits orange-red emission peaks located at 564, 601, 608 and 648 nm attributed to the (4)G(5/2)-> H-6(5/2),(4)G(5/2)-> (6) H-7/2,(4)G(5/2) -> H-6(7/2) and (4)G(5/2)-> H-6(9/2) transitions of the Sm3+ ions correspondingly. In addition, the electronic band structure and density of states for LBSOF and La6Ba4Si6O24F2:Sm3+ are studied by the first principles calculations. The white LED was fabricated by combining a 405 nm chip and blue/green emitting phosphors; the potential of such LED for further applications was demonstrated.