Synthesis and characterization of new D–π-A and A–π-D–π-A type oligothiophene derivatives

In this work, we present a series of newly synthesized conjugated oligothiophene derivatives, with different numbers of central thiophene units, and different donor/ acceptor architectures. Electrochemical and spectroscopic data have also been reported. We used thiophene or bithiophene as central donor core units, 3-octylthiophenes as pi-bridge and solubilizing sub-units, and ethyl cyanoacetate or rhodanine moieties as acceptor end groups, in order to get D-pi-A and A-pi-D-pi-A molecular architectures. The length of the synthesized oligothiophenes ranges from three to eight thiophene units, a variety that is sufficient to put in evidence different optical and electrochemical characteristics as well as semiconducting characteristics. Oligothiophene compounds can be regarded not only as models for the study of structure-property relationships relative to polythiophenes, but also they present a large number of applications in the field of organic electronics (i. e.: as donors in bulk-heterojunction solar cells and hole-transporting layer materials in perovskite solar cells, among others).