Synthesis and luminescent properties of rare earth (Sm3+ and Eu3+) Doped Gd2Ti2O7 pyrochlore nanopowders

• Published in: Optical materials 2014-11, Vol.37, p.598-606
• Main Authors: Ćulubrk, Sanja, Antić, Željka, Marinović-Cincović, Milena, Ahrenkiel, Phillip S., Dramićanin, Miroslav D.
• Format: Article
• Language: English
• Subjects: A. Nanostructures; A. Optical materials; C. Photoluminescence spectroscopy; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; D. Luminescence; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Materials science; Nanocrystalline materials; Nanocrystals and nanoparticles; Nanoscale materials and structures: fabrication and characterization; Optical materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Optics; Physics
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2014.08.001

•Pechini-type synthesis provide rare earth-doped Gd2Ti2O7 nanoparticles of about 20 to 50nm.•The energy levels of the Sm3+ and Eu3+ ions in Gd2Ti2O7 are evaluated.•The strongest emissions are found for Gd2Ti2O7 containing 2.5at.% of Sm3+ and 15at.% Eu3+.•Long emission decays of 5.9ms for Eu3+ and 5ms for Sm3+ in Gd2Ti2O7 are recorded. This work describes the synthesis and photoluminescent properties of rare earth (Sm3+ and Eu3+) doped Gd2Ti2O7 pyrochlore nanopowders. Pure-phase rare earth-doped Gd2Ti2O7 nanoparticles of approximately 20–50nm in diameter, as evidenced from X-ray diffraction and electron microscopy analysis, are produced via the mixed metal–citric acid complex method. A temperature of 880°C is identified for the formation of the crystalline pyrochlore phase, based on a differential thermal analysis of Gd2Ti2O7 precursor gels. From photoluminescence excitation and emission spectra, measured at 10K and room temperature, the energy levels of Sm3+ and Eu3+ ions in Gd2Ti2O7 nanoparticles are obtained. The dependence of luminescence emission intensity and emission decays on rare earth concentration are measured and discussed. The strongest Sm3+ orange–reddish emission is observed for samples containing 2.5at.% of Sm3+ ions, while in the case of Eu3+, the most intense emission is found for 15at.% Eu3+ doping. The 4G5/2 level lifetime decreases with an increase in Sm3+ concentration, from about 5ms (for 0.1–0.2at.% of Sm3+) to 2.4ms (for 2.5at.% of Sm3+). With an increase in Eu3+ concentration in the Gd2Ti2O7 nanoparticles, the Eu3+5D0 level lifetime decreases from ∼5.9ms (for 0.5at.% of Sm3+) to 3.1ms (for 15at.% of Sm3+).