Doping-induced modulation of electronic, optical and wetting properties of CeO₂

Recently, CeO₂ as well as other Rare-Earth Oxides (REOs) have become known as water repelling materials which enables their usage in glass industry. In this study, we investigate electronic, optical and wetting properties of pure and doped CeO₂ by first-principles calculations. It is established that introduction of tetravalent doping atoms (Zr, Ti, Sn and Si) significantly modifies the optical response of CeO₂ in the visible range by shifting the absorption edge which also effects on the refractive index of the material. For these systems, the water contact angle has been computed through adsorption energy of water layers. We report the intrinsic hydrophilicity of the low-index surfaces of CeO₂, which is enhanced by introduction of the impurity atom. Influence of the dopants on the oxygen vacancy formation energy E_f(V_O) is considered and discussed with respect to its possible effect on the hydrophobic behavior of CeO₂. It is found out that all the considered doping atoms reduce E_f(V_O), resulting in enhanced adsorption of the air hydrocarbons at the surface, which leads to an increased water contact angle. Based on the obtained results, an assessment on the applicability of doped CeO₂ in glass industry is made. It is concluded that Zr-doped CeO₂ possesses the most prominent properties among considered systems for the application as transparent layer.