One-step decomposition pathway for solution-derived metal oxide layers driven by hydroxyl radical atmospheres

Abstract

Solution deposition of high-performance oxide films has attracted intense research interest driven by the need for sustainable synthesis strategies that simplify key processes such as ligand removal, oxidation of organic residues, and the formation of amorphous and crystalline oxide phases. These approaches aim not only to reduce the carbon footprint but also to lower the thermal budget required for oxide film formation, thereby enabling direct, large-area deposition on low-cost, temperature-sensitive substrates required for emerging applications in thin-film electronics. In this work, we elucidate the chemical mechanism underlying the crystallization of solution-processed metal oxide films under highly reactive hydroxyl (˙OH) radical atmospheres. These radicals promote a simple, rapid, one-step decomposition of solution-derived films, directly yielding crystalline oxide films with substantially reduced energy input compared with conventional solution-deposition processes. Because this mechanism is independent of solution chemistry and oxide formulation, the platform is broadly applicable to diverse solution chemistries, crystalline oxides, and substrates. As a representative demonstration, BiFeO₃ perovskite films are fabricated on flexible polyimide substrates, producing biocompatible, multifunctional flexible films.