LumiShield

Princia

LumiShield

Transforming windows into smart solar energy-harvesting, light-pollution-blocking systems for sustainable buildings and cities

Falls Church, VA, USA

USA

Nonprofit

Light pollution and fossil fuel dependence are two urgent environmental challenges, each with devastating consequences for public health, biodiversity, and climate stability. Light pollution is a silent killer, affecting over 80% of the global population, with 99% of people in the U.S. living under light-polluted skies. This constant exposure disrupts circadian rhythms and has been linked to severe diseases and disorders, including a 30–50% increase in the risk of breast cancer. Light pollution also contributes to over 600 million bird deaths each year from building collisions and disrupts entire ecosystems. At the same time, buildings account for nearly 40% of global energy use – most of it still powered by fossil fuels. Fossil fuels are responsible for 93% of greenhouse gas emissions and contribute to an estimated 8.7 million premature deaths globally each year. As cities expand and infrastructure lags behind, this dependence on dirty energy disproportionately burdens under-resourced communities. Despite the severity of these challenges, there is still no widely adopted or economically practical solution to address them. Solving them in tandem will require creative technologies that can address sustainability and environmental health together.

LumiShield is a smart window system that helps buildings fight climate change during the day and reduce light pollution at night. It develops and integrates several advanced technologies into one seamless solution: transparent photovoltaic glass, electrochromic film, and a graphene-based supercapacitor. During the day, LumiShield’s photovoltaic layer generates clean electricity from sunlight while remaining see-through. It uses graphene-based electrodes and a perovskite semiconductor to balance transparency with high solar efficiency. That energy is stored in an integrated graphene-based supercapacitor, enabling long-term retention. At night, the electrochromic layer activates, shifting from clear to opaque to prevent artificial light from leaking into the environment. This layer is made of a liquid crystal-embedded polymer matrix that dynamically adjusts visible light transmission in response to low-voltage charges powered by the stored solar energy. The system is fully self-sustaining, requiring no external wiring or grid electricity. In fact, the solar energy it generates not only powers its own light-blocking functionality but can also support building-level electrical needs. All components are integrated within a multilayer glass panel that can be retrofitted into existing buildings. LumiShield offers a dual-impact solution: reducing fossil fuel use by generating renewable energy (providing long-term economic savings) and mitigating light pollution.

LumiShield is designed for building occupants, owners, and communities – particularly in urban areas disproportionately affected by high energy costs, poor air quality, and excessive nighttime light. While these challenges are widespread, their impacts are most deeply felt in under-resourced neighborhoods with aging infrastructure and limited access to sustainable upgrades. Residents in these areas often face higher utility burdens and greater exposure to environmental stressors. Nighttime workers, such as nurses, transit operators, and factory employees, are especially vulnerable to the health impacts of artificial light. Studies have linked chronic light at night to disrupted sleep cycles and a 30-50% increased risk in cancers, such as breast cancer, making light pollution not just an environmental issue, but a serious public health concern. LumiShield offers a scalable, low-maintenance solution tailored to these realities. By harvesting solar energy during the day and preventing artificial light from escaping at night, it lowers reliance on fossil fuels, reduces utility costs, and protects both people and ecosystems. Its retrofit-friendly design ensures it can be installed in existing homes, offices, and hospitals – bringing the benefits of clean technology to communities often left out of the energy transition. Thus, LumiShield supports healthier, more equitable, and more sustainable urban living.