New thiophene-based conjugated macrocycles for optoelectronic applications

GC acknowledges the EPSRC for funding (EP/E036244/1). JMS acknowledges the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 for PhD funding. JMS also acknowledges Dr Nor Basid Adiwibawa Prasetya for helpful advice. Dr L. K. Jagadamma acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776).Thiophene-based semiconductors are amongst the most successful materials in organic electronics. In this contribution, we present the synthesis and characterisation of two thiophene-based macrocycles as well as their evaluation in organic-electronic devices. McT-1 is composed of ten thiophene moieties, whereas in McT-2, four additional electron-deficient benzothiadiazole moieties are incorporated to form a donor–acceptor (D–A) π-system. Red-shifted and broadened absorption spectra as well as more positive redox potentials are observed in McT-2, whereas McT-1 displays a sharper absorption band with a higher extinction coefficient. Macrocycle McT-1 shows emission in the yellow region whereas McT-2 displays emission in the red wavelength region. DFT calculations predict the macrocycles to comprise of mainly the E,E isomers with a near-planar structure, which is further supported by the single crystal X-ray structure for McT-1. Their charge transporting properties are determined by fabricating thin-film OFETs. The photovoltaic properties of McT-1 and McT-2 are also investigated by fabricating bulk heterojunction (BHJ) devices and their potential as photodetectors has been evaluated.Publisher PDFPeer reviewe