Combustion synthesis and photoluminescence study of novel Sm3+ activated K3La(PO4)2 phosphor for n-UV solid state lighting

In the present study, a novel K3La(PO4)2:Sm3+ phosphor was prepared by the combustion method. The synthesized K3La(PO4)2:Sm3+ phosphor was characterized by XRD, SEM, PL (emission and excitation) and color chromaticity. The recorded X-ray diffraction pattern for the phosphor matches JCPDS no. 00–047–0468. From the SEM analysis, the phosphor had an average particle size of 2–25 micrometers and had a solid microcrystalline structure with specific uneven shapes and aggregation between the crystalline grains. The maximum excitation peak occurs at 403 nm, which corresponds to the 6H5/2→4F7/2 transition of the Sm3+ ions. From all the observed transitions, the emission band at 598 nm (6G5/2→6H7/2) shows an orange-red emission with prominent intensity. The emission intensity of the K3La(PO4)2:Sm3+ phosphor could reach a maximum of 1 mol % and then concentration quenching occurs. Further, concentration quenching is explained using Blasse’s equation and Dexter’s theory. The chromaticity findings of the synthesized phosphor had a CIE coordinate of (0.617, 0.381) and hence might be used for an orange-red emission in solid state lighting.