Photo-optical modulation of energy-saving electrochromic windows for high light transmission control

In the quest to reduce energy consumption, smart windows present a core solution to reduce the massive energy loss through windows. Smart windows can be designed on the basis of electrochromic (EC) principles, which offer simple integration mechanisms for color switching, optical sensing, energy harvesting, and energy storage. Photo-optical modulation of the EC window was explored using a thin film of polymer and a redox active electrolyte layer along with a dye-doped photoanode. The integrated photo-electrochromic window (PECW) showed high transparency over 78 % at bleached state but blocked 97 % of light at colored state. Furthermore, the PECW was capable of solar energy harvesting, allowing self-coloration under sunlight. The photo-optical modulation mechanism, material combination, and optimization of an autonomous PECW will be discussed.