Chemically Sustainable Large Stokes Shift Derivatives for High-Performance Large-Area Transparent Luminescent Solar Concentrators

Luminescent solar concentrators (LSCs) have recently emerged as valuable candidates for the realization of aesthetically pleasing solar windows for near-zero-energy consumption buildings. The growing demand by the building-integrated photovoltaic sector is urging the development of sustainable production methods that minimize the use of polluting organic solvents and hazardous materials, while still enabling industrial-grade LSCs. Here, we introduce a new class of benzothieno-benzothiophene (BTBT) derivatives as highly efficient reabsorption-free emitters for transparent LSCs featuring high stability and a solvent-free chemical access with sustainability factor as low as 21, 10 to 50 times lower than conventional LSC emitters. By embedding our BTBT emitters in optical-grade polymeric waveguides, we produced large-area (40 cm(3) 40 cm) LSCs with optical power efficiency as high as 3%(corresponding to an optical quantumefficiency of 54%). These results represent an important advancement toward sustainable solar glazing systems for green architecture.