Vertically aligned nanocomposite films by self‐assembled epitaxial nucleation for super‐broadband transparent conductors

Abstract Designing super‐broadband transparent conductors is challenging because of the exclusive nature of conductivity and infrared transmittance. Here, using a one‐step process, we created vertically aligned nanocomposite conducting films with high transparency across a super‐broad wavelength range. Vertically aligned transparent Ba₃V₂O₈ nanocolumns with lateral ~100‐nm widths enable high transmittance (>50%, even at a 4‐μm wavelength) for all incident light and outperform that of Sn‐doped In₂O₃, while the conducting SrVO₃ matrix retains low resistivity (<0.56 mΩ cm at room temperature). A combined study of scanning transmission electron microscopy, scattering scanning near‐field infrared microscopy, and X‐ray diffraction revealed that spontaneous phase separation of Ba₃V₂O₈ nanocolumns in a SrVO₃ matrix film occurs via self‐assembled epitaxial nucleation. Our vertically aligned nanocomposite films provide a fertile platform for next‐generation optoelectronics.