Dr. Gang Chen
Dr. Gang Chen, Associate Professor of Physics & Astronomy, co-authored an article on “Transparent oxyfluoride glass-ceramics with NaGdF4 nanocrystals doped with Pr3+ and Pr3+-Yb3+.”
Chen is also a member of the Nanoscale & Quantum Phenomena Institute at Ohio University.
Authors: Velazquez, JJ; Balda, R; Fernandez, J; Gorni, G; Pascual, L; Chen, G; Sundararajan, M; Duran, A; Pascual, MJ
Source: JOURNAL OF LUMINESCENCE, Volume 193, p. 61-69; DOI: 10.1016/j.jlumin.2017.07.034
Published: January 2018
Abstract: Transparent oxyfluoride nano-glass-ceramics (GCs) containing NaGdF4 nanocrystals doped with 0.1Pr3+and 0.5Pr3+, and co-doped with 0.5Pr3+-2Yb3+ ions (mol%) were obtained by melting-quenching followed by heat treatments at temperatures near Tg. The addition of rare-earths (RE) ions affects the crystallization kinetics due to the progressive increase of Tg as RE concentration increases. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) show the precipitation of NaGdF4 nanocrystals with sizes between 9 and 30 nm. The crystal size increases with the increasing amount of dopant. Energy dispersive X-ray (EDX) analysis confirms the incorporation of the RE ions in the fluoride nanocrystals in the glass-ceramics. This incorporation is also supported by optical characterization. Photoluminescence measurements shows a better resolved structure together with a narrowing of the Pr3+ emission and excitation spectra in the glass–ceramics compared to the precursor glass. The emission spectra and fluorescence decay curves from the 3P0 level of Pr3+ in the codoped samples support the existence of a Pr3+ → Yb3+ energy transfer with slight enhancement of the energy transfer efficiency in the GC sample.
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