Scalable hybrid solar window with high transparency, high efficiency, and superior color rendering

Abstract

Urbanization and the climate crisis have driven the need for sustainable energy solutions, emphasizing the importance of building-integrated photovoltaic systems and transparent photovoltaic (TPV) modules. However, conventional TPVs face limitations in efficiency, scalability, and color rendering. This study introduces a hybrid solar window combining bifacial silicon solar cells with an optimized distributed Bragg reflector structure to address these challenges. The solar window selectively captures near-infrared light for power generation while transmitting visible light, achieving high transparency (average visible transmittance [AVT]: 75.6%) and superior color rendering (color rendering index [CRI]: 93.8). The experimental results demonstrate a power conversion efficiency of 8.29% and a light-utilization efficiency of 6.27%, exceeding the theoretical limits of non-selective TPVs. Furthermore, the solar window operates effectively under both sunlight and indoor lighting, showcasing its versatility. Its scalable, cost-effective design is compatible with existing building materials and represents a significant advancement toward sustainable urban infrastructure by merging energy generation with architectural functionality.