Fabrication of Hierarchically Structured Porous Films of Metal Oxides and Carbonates Through Coffee Ring Effect

We report a versatile method for the fabrication of hierarchically structured porous ceramic films through a non-vacuum, aerosol-based deposition technique. Our method consists of evaporation of CO2-enriched water microdroplets containing dissolved organic salts and yields a variety of porous scaffolds with micron-sized pores. In addition, the films are characterized by a hierarchy of structural features, such as nanowires, nanorods, 2-dimensional crystals, or nanopores. This scalable, environment-friendly method is applicable to a wide variety of ceramic materials and can lead to materials with an improved performance in catalysis, sensors, solar cells, fuel cells, and tissue engineering.