Spectroscopic properties of K4SrSi3O9 doped with Sm3+

Sm3+ doped K4SrSi3O9 red phosphor, was synthesized for the first time by the conventional solid state method. The X-ray powder diffraction confirmed that obtained phosphor was single phase. Excitation and emission spectra and decay curves were measured to characterize the luminescent properties of the obtained material. K4SrSi3O9:Sm3+ exhibits red-orange luminescence originating mainly from equally intense 4G5/2→6H7/2 (with its maximum at 598.5 nm) and 4G5/2→6H9/2 (at 651 nm) transitions. The luminescence is quenched in the samples doped above 2% of Sm3+ due to non-radiative energy transfer between Sm ions at different sites. The interaction between Sm3+ ions is dipole-quadrupole type and the critical radius for energy transfer was calculated from Inokuti-Hirayama model to be 15.0 Å and 14.2 Å for 300 K and 77 K respectively.