Structure and site selective luminescence of sol–gel derived Eu:Sr2SiO4

• Published in: Journal of luminescence Vol. 132; no. 6; pp. 1329 - 1338
• Main Authors: Gupta, S.K., Mohapatra, M., Kaity, S., Natarajan, V., Godbole, S.V.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2012; Elsevier
• Subjects: Annealing; Atomic force microscopy; CIE index; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diffraction; Eu3; Exact sciences and technology; Judd–Ofelt intensity parameters; Light scattering; Luminescence; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Phosphors; Photoluminescence; Physics; Scanning electron microscopy; Small particles; Sol gel process; Sr2SiO4; Eu3; CIE index; Sr2SiO4; Judd–Ofelt intensity parameters; Photoluminescence; Particle size; Powders; Annealing; Impurity density; Light scattering; Doping; Judd Ofelt effect; Time resolved spectra; Eu; Europium additions; Strontium silicate; Judd-Ofelt intensity parameters; Phosphors; SiO; Chromaticity; Microstructure; Energy transfer; Sr
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2012.01.011

Strontium silicate (Sr2SiO4) samples doped with varying Eu3+content were prepared via sol–gel route and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic light scattering (DLS) and photoluminescence (PL) techniques. The synthesis temperature could be brought down to 600°C for formation of a singe phase sample. The concentration of the dopant ion and the temperature of annealing were optimized for maximum PL intensity. The critical energy-transfer distance for the Eu3+ ions was evaluated based on which the quenching mechanism was verified to be a multipole–multipole interaction. Based on the time-resolved emission data (TRES), it was inferred that, two different types of Eu3+ ions were present in the matrix. The first type was a long lived species (τ=4.7ms) present at 10-coordinated ‘Sr’sites and the other was a short lived species (τ=1.2ms) present at the 9-coordinated ‘Sr’sites which gets selectively excited at 296nm. Judd–Ofelt (J–O) intensity parameters for both the species were evaluated. The trend observed for the two species in the J–O parameters, Ω2 and Ω4 were different confirming their existence in two different environments. The color coordinates of the system were evaluated and plotted on a CIE index diagram. Commercial utility of the phosphor was investigated by comparing it with commercial red phosphor. ► Characterization of Eu3+:Sr2SiO4 samples by XRD, SEM, AFM and PL techniques. ► Optimization of various parameters for maximum luminescence intensity. ► Evidence for the presence of two rare-earth ion sites in the matrix. ► Evaluation of Judd–Ofelt intensity parameters for the two species. ► Evaluation of CIE indices and comparison with commercial phosphor.