Synthesis And Characterization Of Several Polythiophenes

Polythiophene derivatives have good electrochemical properties, environmental stabilityand processability, they have an extremely wide application prospect in biomedicine field,polymer photovoltaic materials.However, polythiophene derivatives for polymer photovoltaicmaterials still exist the problem of low photoelectric conversion efficiency which is inrelevance with the band gap and LUMO orbital energy of the donor material.It is significantto design and synthesis polythiophene derivatives with novel structure,and to measure theiroptical and electrical properties for selecting excellent photovoltaic materials.In the paper several novel polythiophene derivatives with biphenyl and azophenyl in theconjugated chain of polythiophene derivatives were synthesized and cross-linkedpolythiophenes were synthesized too. The optical-electrical properties of all the abovecompounds were measured.The specific research is as follows:With4,4′-dibromobiphenyl as basic materials,4,4′-di(2-thieyl)biphenyl was synthesizedvia Suzuki coupling reaction,and4,4′-di(2-thienyl)-2-nitrobiphenyl was synthesized vianitration and Suzuki coupling reaction. the two biphenylyl-thiophene derivatives werepolymerized by chemical oxidative polymerization with ferric chloride as oxidizing reagent tosynthesize polythiophenes containing biphenyl in the conjugated chain.With p-aminoacetanillide as raw material,4,4′-di (2-thienyl) azobenzene was synthesizedvia oxidation, acid hydrolysis, Sandmeyer, and Suzuki coupling reaction. Poly[4,4′-di(2-thienyl)azobenzene] was synthesized by chemical oxidative polymerization with ferricchloride as oxidizing reagent.With thiophene and2-thiophenecarboxaldehyde as basic materials, tri(2-thienyl)methanewhich is used as crosslinker was synthesized by phosphorus pentoxide as dehydrator.Thecrosslinker was crosslinked with3-hexylthiophene, then conjugated cross-linkedpoly(3-hexylthiophene) was prepared with DDQ as oxidant.All the thiophene derivatives and the cross-linker were characterization by IR and1H-NMR.The morphology of the polymers were characterized by SEM;the optical propertieswere characterized by UV-vis and fluorescence spectroscopy;the electrochemical propertieswere recorded by Cyclic voltammetry, and the band gap and orbital energy were calculated.