Angular-Shaped 4,10-Dialkylanthradiselenophene and Its Donor–Acceptor Conjugated Polymers: Synthesis, Physical, Transistor, and Photovoltaic Properties

An angular-shaped and isomerically pure 4,10-di(2-octyl)dodecylanthradiselenophene (aADS) was successfully developed. The expedient synthesis to form the framework of aADS with two lateral side chains regioselectively at its 4,10-positions is via a base-induced propargyl–allenyl isomerization/6π-electrocyclization/aromatization protocol. This pentacyclic distannylated aADS unit was then copolymerized with dithienyldiketopyrrolopyrrole (DPP) and dithienyl-5,6-difluoro-2,1,3-benzothiadiazole (DTFBT) acceptors with different alkyl side chains to afford four donor–acceptor copolymers: PaADSDPP, PaADSDTFBT-C4, PaADSDTFBT-C8, and PaADSDTFBT-C8C12. UV–vis spectroscopy and cyclic voltammetry revealed that PaADSDPP has the narrowest energy band gap, and PaADSDTFBT-C8C12 has larger band gap than PaADSDTFBT-C4 and PaADSDTFBT-C8. Two layer ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) calculations were implemented to investigate the disparity in optical, electrochemical, and device pr...