Electrofluorochromism in π-conjugated ionic liquid crystals

Amerigo Beneduci, Sante Cospito, Massimo La Deda, Lucia Veltri, Giuseppe Chidichimo
2014 Nature Communications  
Materials in which photoluminescence is modulated by redox processes are known as electrofluorochromic. Intrinsically switchable fluorophores, incorporating both redox and fluorescent moieties, could be ideal electrofluorochromic materials if they possess high fluorescence quantum yields in at least one of their redox states. Fluorescent liquid crystals with redox active centres could combine the above requirements with the advantage to work in bulk anisotropic phases. However,
more » ... mic liquid crystals have not been reported yet because their synthesis is challenging due to aggregation-caused fluorescent quenching. Here we show the first examples of electrofluorochromic p-conjugated ionic liquid crystals based on thienoviologens. These ordered materials, combining ionic and electronic functions, are highly fluorescence in the bulk state (quantum yield460%). Their direct electrochemical reduction leads to fast and reversible bulk electrofluorochromic response in both columnar and smectic phases allowing for fluorescence intensity modulation and colour tuning.
doi:10.1038/ncomms4105 pmid:24445388 fatcat:gjcndm55t5hj3o5qetzkvfvxpy