Electrochromic device with hierarchical metal mesh electrodes: Transmittance switching in the full spectral range of solar radiation

Hierarchical metal mesh structures are fabricated for use as transparent conductive electrodes in electrochromic devices with large-band transmittance switching. Electrochromic materials (WO3 and Ta:NiO) are deposited by plasma sputtering on the metal mesh and characterized in a custom-made electrochemical setup allowing in-situ photo-spectrometer measurement. Both films deposited on metal mesh exhibit high transmittance, not only in the visible but also in the NIR spectrum. Electrochromic devices based on the WO3 cathode and Ta:NiO anode combined with the hierarchical metal mesh are fabricated. The resulting device achieves remarkable optical modulation in the full spectral range of solar radiation compared to conventional ITO-based devices. This study paves the way for development of hierarchical metal mesh-based electrochromic devices which offer high potential for energy savings through wide band modulation of solar heat gain in buildings in countries with warm and cold seasons.