Structural, optical and photoluminescence characteristics of apatite type lanthanide silicates

Abstract

This article reports the solid state synthesis of apatite type rare earth-transition metal silicates Nd4MnSi3O13 and Sm4MnSi3O13. These oxyapatite type lanthanide silicates were characterized through structural, micro structural, optical and photoluminescence properties. The indexed X-ray diffraction patterns and Raman analysis confirm that both the samples crystallize in single phase hexagonal symmetry with space group P63/m. Transmission electron microscopy images along with electron diffraction pattern indicate the good crystalline nature of both the samples which further support the results obtained from X-ray diffraction study. The optical band gap energies are found to be 4.1 eV and 3.9 eV for Nd4MnSi3O13 and Sm4MnSi3O13 respectively. The wide optical band gap values of these semiconductor silicates make enable them for fundamental and technological applications. The luminescent properties and CIE coordinates showed the green-yellow emission of these synthesized silicates which further indicate that these compounds may have uses in solid state lighting because of the tunable luminescence.