Surface morphology-driven stability of the hydrophobic Er2O3 films
Joanna Borowiec, Claire J. Carmalt, Matthew O. Blunt, Ivan P. Parkin
Abstract
Hydrophobic coatings have emerged as an indispensable element in enhancing the efficiency and durability of photovoltaic systems, bringing a critical advancement to energy harvesting technologies. This work realizes stable hydrophobic erbium (III) oxide (Er 2 O 3 ) coatings using surface topography engineering. The controlled growth of the films was achieved using aerosol assisted chemical vapor deposition (AACVD) from air stable Er(III) β-diketonate complex. AACVD produced hydrophobic Er 2 O 3 films exhibiting water contact angles above 90°, with the highest reaching 98°. The fundamental principles underlying water repelling properties of the Er 2 O 3 films were assessed in detail via comprehensive physico-chemical characterization. The best performing films maintained WCA stability and were resistant to WCA alteration induced by surface topography which has been shown through time dependent study. This work demonstrates evidence of an intrinsic hydrophobicity of the Er 2 O 3 coating and its long-time stability. • New AACVD protocol for synthesis of hydrophobic E2O3 coating is presented. • The Er2O3 films surface morphology grown on the FTO ensured its stable hydrophobicity with WCAs of 98°. • The AACVD enables the cost-effective deposition of hydrophobic Er₂O₃ films at 450°C with tailored surface morphology, enhancing both deposition efficiency and film performance. • We have demonstrated experimentally that there is a clear relationship between the Er2O3 wettability, its surface chemical composition and material physico-chemical properties. • The high transparency of Er₂O₃ films ensures compatibility with photovoltaic modules, while their stable hydrophobicity have a potential to reduce maintenance requirements and costs.