Synthesis and spectroscopic investigations of trivalent europium-doped M2SiO5 (M = Y and Gd) nanophosphor for display applications

Abstract

Synthesis of trivalent europium ion-doped Y2SiO5 (YSO) and Gd2SiO5 (GSO) was carried out via sol–gel combustion technique using organic fuel. The optical and structural properties of these phosphors were analyzed. The structural investigations of the samples were studied using X-ray diffraction (XRD), Fourier transformation infrared (FTIR) and transmission electron microscopy (TEM). XRD patterns show monoclinic crystal lattice (space group P21/c) for M2SiO5 (M = Y and Gd) host materials, irrespective of metals (Y and Gd) and change in temperature upto 1050 °C. The increased intensity of XRD peaks with rise in temperature indicates the increase in crystalline nature of the phosphors. FTIR bands at 880–1020 cm−1 confirm the presence of SiO4 tetrahedra with layered structure and support XRD results. TEM images depict the spherical nanoparticles with filled morphology, narrow size distribution and slightly agglomerated crystallites of the samples. The crystallite sizes of phosphors from TEM analysis are promising with that calculated by Scherer’s formula using XRD data. Energy-dispersive X-ray analysis (EDAX) shows the composition of elements present in small area of sample. The spectra show a number of peaks that belongs to various elements integrated with the host framework. The photoluminescence (PL) emission spectra of Eu3+-doped samples showed 5D0 → 7Fj (j = 1, 2 and 3) transitions under 393–394 nm excitation. Strong red emission corresponding to hypersensitive 5D0 → 7F2 transition (611 nm) suggested the presence of Eu3+ ions in a site having absence of centre of symmetry. Due to advantageous properties such as intense photoluminescence and high crystallinity these nanophosphors could possess potential applications in the mercury-free lighting sources and modern display devices.