Fluorescent organic materials for applications in energy and communication

Luminescent solar concentrators (LSCs) are large-area optical devices, capable of harvesting, downshifting and concentrating solar light, thanks to the presence of emitting materials embedded in a polymer matrix. These materials can be used together with silicon-based photovoltaic (PV), to obtain photovoltaic devices able to capture diffuse light. These features with the aesthetic characteristics (colour and shape tunability), allow their use in building-integrated photovoltaics (BIPVs). The same materials could be used as an antenna in Visible light communication (VLC), one of the most promising candidates for implementing the future 6G communication paradigm. VLC exploits ordinary LED sources to cast data over the air besides providing for illumination. In this scenario, exploiting the full spectrum of white LED sources is essential to achieve reliable and efficient VLC links, in the so-called Li-Fi approach. In order to obtain high-performance LSC devices for both photovoltaic and VLC, a careful study of the materials used for their assembly must be performed, both concerning the selection of the fluorophore and the plastic material in which it is dispersed. We recently synthetized and investigated the properties of a series of organic fluorophores with donor-acceptor-donor (D-A-D) structure, characterized by quinoxaline and benzodithiophene tetraoxide as acceptor cores. The optical properties of the molecules were investigated in solution as well as after dispersion in the polymer matrix. The best LSC built with these compounds presented photonic and PV performances close to the state-of-the-art. Moreover, we demonstrated efficient VLC communication using one of these fluorophores. We compared the performances with the state-of-the-art demonstrating the possibility to employ our fluorophore in white-light VLC applications.