Tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionate) Cerium for the Deposition of Hydrophobic Coatings

Cerium oxide thin films represent an important approach to hydrophobic, self-cleaning solar modules, offering significant potential for photovoltaic applications. These coatings provide a durable, long-lasting alternative to conventional self-cleaning surface technologies, which often rely on polymer-based films prone to degradation over time. Here, we present the synthesis of tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionate) cerium ([Ce(thd)₄]) for the deposition of hydrophobic cerium oxide thin films by aerosol-assisted chemical vapor deposition (AACVD). The use of [Ce(thd)₄] as a precursor led to the deposition of cerium oxide coatings onto fluorine-doped tin oxide (FTO)-coated glass substrates. Water contact angles (WCA's) of 91-101.1° were observed for films deposited at temperatures of 400-500 °C. Investigation into the influence of the substrate on the hydrophobicity of cerium oxide films demonstrated that FTO-coated glass offers a more favorable surface morphology compared to that of barrier glass. The deposited cerium oxide thin films were characterized by surface analysis techniques for the different deposition temperatures. X-ray photoelectron spectroscopy (XPS) analysis of the adhered thin films revealed a transition from a mixed-phase system of Ce³⁺ and Ce⁴⁺ to a composition dominated exclusively by Ce⁴⁺.