Large-area luminescent solar concentrators with high optical clarity towards integration with smart windows

Luminescent solar concentrators (LSCs), or “solar windows,” are emerging as viable solutions for building-integrated photovoltaics (BIPVs). As they serve as both power generators and glazing units, maintaining high optical clarity is key. In this work, we present a large-area (>800 cm²) silicon quantum dot (Si QD)-based LSC, combining high aesthetics, durability, and photovoltaic performance. It has an average visible transmittance (AVT) of 83% and negligible haze, enabled by a customized UV-curing system and optimized QD loading in polymer. This prototype exhibits the lowest attenuation coefficient for waveguided luminescence, to the best of our knowledge, among reported values for all LSC systems. It can deliver a power conversion efficiency (PCE) of up to 1.24% with back reflection. Remarkedly, long-term durability is demonstrated through 3000 h of accelerated UV aging (UV-340 nm, 40 °C), equivalent to ∼3 years of sunlight exposure. Photon and power budget measurements reveal that this device can fully power electrochromic (EC) or polymer-dispersed liquid crystal (PDLC) smart windows of equal size, without compromising transparency and functionality. These results underscore the potential of Si QD-LSCs as benign scalable photovoltaic glazing for future buildings.