LE3 .A278 2012

2012

van der Ende, Bryan

Acadia University

Bachelors of Science

Honours

Physics

Physics

This thesis examines the down conversion potential of phosphors YVO4 and GdVO4. The dopant used in this investigation of down conversion was ytterbium. The experiments described involve the emission of the phosphors at several excitation wavelengths, the excitation spectra of the said phosphors and their synchronized spectral emission. Specifically, emission, excitation and synchronized spectra were recorded for Yb:YVO4 samples and emission and excitation spectra were recorded for Yb:GdVO4 samples. The excitation spectra of the Yb3+ doped samples where Yb3+ emission intensity was monitored at 986 nm showed host lattice absorption peaks. This directly confirmed the energy transfer from the host lattice to the Yb3+. Emission spectra corrected for instrument response were used to estimate down-conversion quantum efficiency. For Yb:YVO4, down-conversion efficiency estimates ranged from 110% (0.5% Yb3+) to 269% (8% Yb3+). For Yb:GdVO4, down-conversion efficiency estimates ranged from 131% (0.5% Yb3+) to 256% (4% Yb3+). The implications and reliability of these estimates are discussed. Synchronized spectra measured Yb3+ absorption in the near-infrared, ! 6! confirming that with increasing dopant concentration comes increasing absorption strength.

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https://scholar.acadiau.ca/islandora/object/theses:919