Multi-color poly(3-methylthiophene) films prepared by a novel pre-nucleation electrodeposition grown method for enhancing electrochromic stability

Poly(3-methylthiophene) (PMeT) is considered a promising conductive polymer for applications in electrochromic displays due to its red to blue multi-color switch as well as low cost. However, the non-uniformity of the films caused by high electrochemical polymerization potentials during electrodeposition and the rapid electrochemical stability decay caused by weak adhesion limits its practical application. In this study, a new pre-nucleation electrodeposition method is developed to synthesize PMeT film. The nucleation grown progress is investigated by electrochemical fitting tests and scanning electron microscopy. Compared with a directly grown film, the pre-nucleation PMeT film presents excellent electrochromic EC transmittance modulation of 75% at wavelength of 1050nm, and sustains a transmittance modulation of about 91 % after 400 cycles. This was the result of enhanced uniformity and adhesion from the pre-nucleation method. The surface uniformity and roughness of PMeT films were analyzed by optical microscopy and atomic force microscopy measurements. After controlling thickness using this method, the PMeT films exhibited multiple transmittance change and red-green-blue color change. (C) 2020 Elsevier Ltd. All rights reserved.