Smart Photovoltaic-Integrated Electrochromic Window for Solar Energy Harvesting and Light Pollution Mitigation

This research presents the development and characterization of a novel photovoltaic-integrated electrochromic window (PIEW) to serve the dual purpose of addressing urban light pollution and renewable energy generation. The system comprises of semi-transparent glass photovoltaic cells using graphene-based photoactive layers, a graphene-based supercapacitor for efficient energy storage and delivery, and an electrochromic layer for adaptive opacity control, to allow solar energy harvesting in daylight and provide automated light emission control at night. The photovoltaic element has an efficiency of 7.1%, with 69.8% visible light transmission. During nighttime hours, the electrochromic layer utilizes the stored energy to switch to a state in which 89.0% of light is prevented from escaping, thereby substantially reducing the light pollution from building interiors to the outdoors. An integrated microcontroller-based management system enables self-sustaining operation both during the day and at night, while the supercapacitor efficiently delivers the power needed for the electrochromic transitions. This work therefore establishes a viable approach for the tackling of two urban sustainability challenges – renewable energy generation and light pollution mitigation – in a single solution, while highlighting key areas for future optimization in charge transport dynamics and interface engineering.