Experimental and first-principles study on the effect of oxygen vacancy on infrared emissivity of CeO₂

Ceria is considered a potential candidate for high-temperature infrared stealth materials due to its high melting point, oxidation resistance and low infrared emissivity. As reported, the infrared emissivity of ceria can be reduced after high temperature treatment. However, the available researchers have only analyzed the reasons for this change from the aspect of microstructure morphology. In this study, ceria with different oxygen vacancy concentrations were obtained by heat treatment of ceria powder at different temperatures and their infrared emissivities in 2.5–14 μm were characterized. The experimental results show that with the increase of heat treatment temperature, the oxygen concentration increases and the emissivity decreases. The electronic structure and reflectivity of ceria at different oxygen vacancy concentrations were obtained by first-principles calculations. The calculated results show that the reflectivity of ceria and the DOS peak area near the Fermi level increase with increasing oxygen vacancy concentration. Through this study, we demonstrate that the emissivity of ceria decreases with increasing oxygen vacancy concentrations, which is due to the increase in free carrier concentration.