Flexible Metal Mesh Electrode for Infrared Variable Electrochromic Device

Electrochromic devices (ECDs) have garnered significant attention for their ability to control both infrared (IR) and visible light transmission. This feature makes them particularly suitable for applications such as reflective displays and camouflage technology. In camouflage, ECDs are useful for evading thermal infrared sensors and disrupting enemy awareness. A typical ECD consists of two transparent electrodes with a thin film containing two electrochromic materials, such as tungsten trioxide (WO₃), sandwiched between them. However, the widely used transparent electrode, Indium Tin Oxide (ITO), has poor infrared light transmission. Therefore, there is a need for an alternative electrode with better IR transparency.
Among flexible transparent electrodes, mesh-type transparent electrodes have gained special interest due to their excellent combination of high conductivity and transparency, made possible by their mesh structure. The thin and sparse mesh structure allows for high visible light transmission while also enabling middle-wavelength infrared (MWIR) light to pass through. However, mesh-type electrodes typically exhibit slow and non-uniform electrochromic switching (blooming effect) due to inconsistencies in sheet resistance. This study outlines the fabrication process of metal mesh-type electrodes on flexible substrates, proposes a method to address the blooming effect, and presents ECDs tunable from visible light to MWIR as a solution.