Synthesis And Applications Of Linear Oligothiophene Derivatives

As a new kind of organic functional material, oligothiophene is getting more and more attention because of its excellent optoelectronic properties, anti-surroundings. In order to enlarge the application of this kind of material, a series of oligothiophene and its derivatives: 2,6-bis(2,2′-bithiophene-5-yl)pyridine(B2TPY), 5-formyl-2,2′-bithiophene(2T-CHO), 5,5′-bi- formyl-2,2′-bithiophene(2T-2CHO), 2,2′:5′,2″:5″,2″′-quaterthiophene(4T), 5,5″′-biformyl-2,2′: 5′,2″:5″,2″′-quaterthiophene (4T-2CHO) and 5,5″′-bicyano-2,2′:5′,2″:5″,2″′-quaterthiophene (4T-2CN) were designed and synthesized. Their molecular structures were charactered by MS, NMR, IR and HPLC.The photophysical and electrochemical properties of these oligothiophene derivatives were measured by UV-vis absorption spectra, fluorescence spectra and cyclic voltammetry.Complexes of B2TPY with rare-earth Terbium(Tb) and Europium(Eu) were prepared and charactered by IR, and their fluorescence spectras indicated that the energy transferation from the triplet state to single state was completed.The photovoltaic performances of 4T, 4T-2CHO and 4T-2CN were investigated by the hard and flexible heterojunction organic photovoltaic devices. It was found that the best photoelectric conversion (PCE) efficiency of photovoltaic cells had reached 2.74% in the hard devices and 1.94% in the flexible devices.The electrochromic property of 4T-2CHO was studied. The result showed the reversible color changes of the electrochemical doped film of 4T-2CHO was from orange to reddish brown. The result also suggested it had great potential as a new type of electrochromic material.