Covalently linked thieno[2,3-]thiophene-fullerene dimers: synthesis and physical characterization.

Thienothiophene (TT) has received great attention in the fields of electronics and optoelectronics. Here we report a synthesis and characterization of fullerene-donor-fullerene triads linked to thieno[2,3-]thiophene as a donor. The photophysical and electrochemical properties of the new dumbbells were investigated using UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and square wave voltammetry. The results showed that both compounds have higher LUMO energy levels than PCBM, indicating that they can be used in photovoltaic applications. Furthermore, the powder was structurally and morphologically characterized X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SEM revealed the morphological characterization of the two derivatives as globular and urchin-like supramolecular assemblies.