Reliable fabrication of vanadium-based films and their visible-infrared spectral compatibility modulation

Vanadium pentoxide (V₂O₅) films exhibit rich electrochemical activity and color variation when combined with Li⁺ intercalation. Efficient fabrication of these films is essential for the development of smart optoelectronic displays. This study employs an electrochemical deposition method to achieve low-cost, large-area growth of V₂O₅ films on multiple substrates at room temperature. By depositing V₂O₅ films on ITO substrates and using external field-driven electron-proton synergistic operation, six different color states were achieved. The elemental composition and valence states of the films after Li⁺ intercalation were analyzed by transmittance spectral analysis and X-ray photoelectron spectroscopy (XPS). It was quantitatively confirmed that not only V⁴⁺ but also a considerable proportion of V³⁺ was generated in the films under the negative-voltage coloring state, this finding breaks with the conventional knowledge of the coloring end state of V₂O₅ films. Meanwhile, electrochemical Li ⁺ intercalation enables tunable infrared emissivity of the V₂O₅ films, resulting in a temperature difference of ∼7 °C between the positive and negative voltage intercalation states and highlighting their potential application in dynamic visible-infrared camouflage. This visible-to-infrared dual-mode modulation operates independently of ambient temperature and does not rely on VO₂ phase transitions. Combined with photolithographic masks to form optically patterned displays, it provides theoretical and technical support for novel vanadium-based optoelectronic displays.