Abstract
Powdered zirconia and colloidal zirconia aqueous sols have been examined by diffuse reflectance and absorption spectroscopies and by photoluminescence methods in solid/gas and solid/liquid systems. The former system was examined following high-temperature treatment in vacuo and under reducing and oxidizing atmospheres. Studies of the influence of H2 and O2 on the photophysics of microparticles (powder) and nanoparticles (colloidal sols) of zirconia at solid/gas interfaces and the effects of free carrier scavengers (CH3OH and O2) on the photophysics at solid/liquid interfaces were undertaken to explore the correlation between surface chemistry and the nature of preexisting or photogenerated defect centers (e.g., F-type and V-type color centers). ZrO2 is an insulating, direct wide-gap metal oxide with an optical band gap of ∼5.0 eV; another optical transition occurs at 5.85 eV. The optical behavior depends on whether zirconia is preirradiated in the intrinsic (hν > 5.0 eV) or extrinsic (hν < 5.0 eV) absorpt...
Published Version
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