Growth of conductive indium tin oxide (ITO) nanoparticles by mineralization in ring-shaped biomimetic templates

Indium tin oxide (ITO) nanoparticles were synthesized by mineralization in the cavity of ring-shaped templates that were generated by the self-assembly of peptide-based biomimetic molecules. The ITO nanoparticles grew to an average diameter of 150 nm. This exclusive ITO nanoparticle growth was driven by the catalytic property of the biomimetic template, and growth was only observed when the biomimetic template was present in the reaction mixture. Due to the interaction of the biomimetic template with the indium ion, the crystalline structure of the ITO nanoparticles was transformed to a fluorite (CaF ₂) structure, in contrast to the hexagonal structure of those prepared by coprecipitation. In addition, the synthesized ITO nanoparticles showed a lowered bias voltage compared to those prepared without the peptide-derivative assembly. These findings indicate that mineralization using a biomimetic template is a promising method to produce functional nanomaterials at room temperature, allowing for control of the shape, crystalline structure, and physical properties of the nanoparticles.