Investigation of the electrochromic properties of tri-block polyaniline-polythiophene-polyaniline under visible light

•Novel tri-block copolymers of polyaniline-polythiophene-polyaniline.•Film of tri-block copolymer has good electrochromic switching stability with an application of voltage at +1.4/−1.4 Vdc under light irradiation at ambient conditions.•Polyaniline blocks increased polymer films stability.

This paper describes the synthesis and electrochromic properties of a novel soluble polyaniline-polythiophene-polyaniline tri-block copolymer. The measurements of optical absorbance as a function of voltage and time on tri-block copolymer thin films demonstrated an improvement in stability at ambient conditions and visible light irradiation during the application of voltages. Switching experiments showed an improvement of stability of tri-block copolymer up to 3 times in comparison to the polythiophene block only. A comparison of optical absorbance characteristics for the tri-block copolymer relative to the polyhiophene block indicated that the polyaniline blocks substantially increased film stability and therefore has influence on the optical and electrochemical properties of tri-block polyaniline-polythiophene-polyaniline.

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