Structural,morphological and photoluminescence characteristics of sol-gel derived nano phase CeO2 films deposited using citric acid

Homogenous nano structured CeO₂ films have been prepared by a sol-gel process using different mole ratios of citric acid as additive. XPS studies clearly illustrate an increase in Ce³⁺ proportion upon the use of higher citric acid content for the deposition of films. The crystallite sizes in the films lie in the nanorange. Photoluminescence emission in the films is attributed to various defects resulting from crystallization. Lowest transparency, high Ce³⁺ content and optimum sized crystallites in CeO₂ (1:1.5) films have led to its highest PL characteristics. Ce³⁺ chemical state is the major contributor to the PL activity of these films. The SEM micrographs show a reduced level of CeO₂ agglomeration in the films deposited using higher citric acid contents. A comparison of different properties of CeO₂ films deposited using citric acid and CeO₂–TiO₂ films has also been made.