Design and development of new organic molecules as alternative fluorophores for LSC application

Presently, Luminescent Solar Concentrators (LSCs) are considered promising alternative optical devices for the sunlight harvest and production of energy. A LSC is composed by a thin transparent polymer slab, doped with a fluorophore able to absorb solar radiation and concentrate it, at a specific wavelength, at the edges of the slab, where a thin PV cell can capture and use to produce electricity. Due to the low-priced materials and their innovative aesthetic properties, LSCs find an easy integration in architectural systems, such as roofs, windows, canopies and greenhouse. The heart of LSC device remains fluorophore, which needs to follow several optoelectronic properties: broad absorption range, long-wavelength emission maximum, large Stokes shift, high fluorescence quantum yield, low-priced materials and production, good optical efficiency and good dispersion in the host materials. The organic molecules are more versatile class of luminophores, which can largely satisfy LSC requirements, due to their close relationship between molecular design and optoelectronic tunability. During this Ph.D., keeping in mind all these targets, a careful and specific molecular design supported by computational analysis have been accomplished. Three classes of new organic fluorophores characterized by D-A-D structure have been planned and executed. The synthetic optimization and the employment of sustainable procedures have been carried out when possible, favoring cross-coupling reactions and more eco-friendly approaches. All organic chromophores have spectroscopically characterized in solution and polymer dispersion, designing a common prototype of LSC device for all chromophores. Alternative matrices have been tested to evaluate their impact on optoelectronic properties of the various fluorophores. LSC performances of each chromophore have been assessed and compared with those of literature reference Lumogen F Red 305 (LR305).