The realization of electrochromic (EC) devices capable of achieving independent control over the visible and near infrared regions of the solar spectrum still remains an unmet key target in the perspective of making EC glazings really attractive for the next generation of advanced dynamic building facades.

We report on the fabrication of a set of EC devices embodying engineered nanostructured electrodes made by 1D high aspect-ratio tungsten oxide nanocrystals having a specifically controlled crystal structure, which have been prepared by a suitable non-hydrolytic route.

They allow for widely tuning of the spectroelectrochemical response, which closely matches the solar spectrum, and for selectively controlling the sunlight transmission over the near-infrared to visible range.

These systems can be finely regulated through an appropriate control of two fundamental electrochemical processes occurring at the interface between the nanostructured EC electrode and the electrolyte, namely, (i) the capacitive surface charging/discharging, which is responsible of the optical density modulation in the near-infrared range at relatively low applied potentials, and (ii) the faradic current-driven Li⁺ insertion/deinsertion, which allows for a remarkable modulation of the visible absorption at higher potentials.