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, optimized QD loading in polymer, and ultralow-iron glass as waveguides. This prototype exhibits a record-low attenuation coefficient for waveguided luminescence among all LSC systems. It can deliver a power conversion efficiency (PCE) of up to 1.24% under white back reflection. Remarkedly, long-term durability is demonstrated through 3000 hours 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.