Sustainable by design, large Stokes shift benzothiadiazole derivatives for efficient luminescent solar concentrators

Luminescent solar concentrators (LSCs) are becoming an increasingly relevant topic for buildingintegrated photovoltaics. Even if such devices are relatively simple planar waveguides doped with aluminescent material, the achievement of relevant efficiencies requires a careful optimisation of both thematrix and the luminophore. Most of the recent literature focuses on the performance, yet the overallsustainability of the strategy is a topic at least as important. In this respect the luminophore plays acrucial role. Suitable materials must feature a near unit emission quantum yield, efficient light harvestingand a large separation between absorption and emission to reduce reabsorption losses. Due to thetarget application, such materials must also be readily available in large quantities through sustainableprocesses. Instead of going for performance first and then scaling up/optimising the synthesis, in thispaper we offer a reversed perspective. We have first designed and computationally characterisedmaterials having structural features compatible with a green chemistry synthetic approach, namely,micellar catalysis. Later, we have characterised the most promising materials in LSC devices, and wehave compared their performance with commercially available, non-green chemistry compliantalternatives having similar spectral features. In the overall, we demonstrate comparable performance,but greatly improved sustainability and scalability.