The photoluminescence properties and reversible photoinduced spectral change of CeO_2bulk, film and nanocrystals

摘要

The photoluminescence properties of different pristine C_eO_2specimens (bulk crystal, film, and nanocrystals) have beenstudied at different temperatures between 7 K and roomtemperature. The photoinduced luminescence spectral changehas been observed at room temperature for the first time.The phenomenon observed in a vacuum is explained as aphotoinduced associative detachment of O_2on the specimensurface, while that observed in O_2gas is explained as a photoinduced dissociative adsorption of O_2on the specimensurface. The photoreduction is accompanied both by a valencenumber change of cerium ions (Ce~(4+)→Ce~(3+)) and by oxygen-defect formation. Such reversible photoinduced phenomena ofCeO_2can be applied to light control of the oxygen-storage andoxygen-release processes at metal-oxide surfaces. A tentativeresult obtained at room temperature for an oxygen-storagematerial (0.3)C_eO_2-(0.7)ZrO_2solid solution is also described.