Three new 2, 5-di(2-thienyl)-1H-pyrrole(DTP) derivatives, 10-[4-(2,5-Di- thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-pheno-thiazine (TPPT), 10-[4-(2,5-Di- thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-phenox azine (TPPO) and 10- [4-(2,5 -Di-thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-acridin-9-one (TPAO), were synthesized and characterized. TPPT and TPPO showed similar absorption and emission feature owing to similar chemical structure, TPAO displayed bathochromic-shift for both absorption and emission feature due to the existence of ketone group. All the monomers could be electropolymerized to form their polymer film on the electrode surface via oxidative coupling reactions of DTP units. PTPPT film showed yellow-green, green and purple red color upon different applied potentials. PTPPO and PTPAO films exhibited green and yellow at the neutral state, respectively, and turned into the similar violet color for the oxidized state. Moreover, the copolymer P(TPPT/EDOT) and P(TPAO/EDOT) not only showed obvious color change(red, yellow, green and blue), but also possessed better electrochemical stability.

Phenoxazine, as an organic-small-molecule chromophore, has attracted much attention for its potential electrochromic applications recently. To develop appealing materials, phenoxazine chromophores were introduced at the N-position of carbazole–thiophene pigment, yielding two novel monomers (DTCP and DDCP), whose chemical structures were characterized by NMR, HRMS and FTIR. The results of the optical property study indicate that little influence could be observed in the presence of the phenoxazine chromophore. Corresponding polymer films on the surface of an ITO/glass electrode were obtained through electropolymerization. The electrochemical features displayed were various due to the introduction of the phenoxazine group. The spectroelectrochemical results demonstrate that the color of the polymer films could be changed. Compared with the PDDC films, the PDDCP films exhibited three different colors (tangerine, green and purple colors) in different redox states, which could be attributed to the synergistic effect between the carbazole–thiophene conjugate chain and the phenoxazine group. Moreover, fast switching time could be seen due to the presence of the phenoxazine chromophore. This study could provide a reference for obtaining high-performance electrochromic materials.

Carbazole, triphenylamine and thiophene derivatives have received great interest due to their outstanding electrochemical and electrochromic performance. In this study, four novel monomers based on carbazole-thiophene and triphenylamine derivatives (BTC-TPA, BTC-DMTPA, DTC-TPA and DTC-DMTPA) were synthesized and characterized. The obtained monomers could form corresponding polymer films on the surface of ITO/glass electrode by electropolymerization. Electrochemical properties and morphology of the polymer films were investigated. Spectroelectrochemical measurements demonstrated that the polymer films could exhibit multi-color electrochromism, especially for P(DTC-TPA) film, which could show four different colors(brown-green, blue gray, blue and purple black) at different redox states. Moreover, all the polymer films also possessed good optical contrast, reasonable switching time and coloration efficiency. These finding implied that the obtained polymer films could be considered as good candidates for the opto-electronic applications.