Morphology and electrochromic properties of nanostructured polyterthiophene films formed by different deposition modes

Abstract Nanostructured electrochromic polymer (ECP) materials are commonly explored in electrochromic devices (ECDs) because of their fast switching speed, high coloration efficiency and long cycle life. However, the preparation of nanostructured ECP films with a single component is still a great challenge. Herein, we present a facile, efficient, low-cost strategy to construct three-dimensional reticular macroporous (3DRM) ECP films without using templates. Polyterthiophene (PTTh) is selected as the model polymer due to its good EC behaviour. The 3DRM PTTh films on indium tin oxide (ITO) glass are fabricated by potentiostatic deposition (PSD) and pulsed electrodeposition (PED) of terthiophene (TTh), and further assembled into the ECDs. We investigate the morphology, structure and electrochemical properties of PTTh films, and EC performance of corresponding ECDs. The results indicate that the PTTh film with a PED time of 240 s (PTTh-PED-240) possesses loose 3DRM morphology and large surface area. The EC properties of corresponding ECD is significantly enhanced, exhibiting a large optical contrast, high coloration efficiency, short switching time, and improved cycling. Compared with the ECD based on PTTh film with a PSD time of 120 s on ITO glass (PTTh-PSD-120/ITO), the optical contrast of ECD based on PTTh-PED-240/ITO (ECD-240) increases by 45% (31 → 45%), and its coloration efficiency increases by 107% (258 → 534 cm2/C). This study suggests that PED might be a facile strategy for fabricating high-performance nanostructured ECP films, and its preparation process is low-cost, easily conducted under ambient conditions, showing great potential applications in nanostructured polymer-based ECDs.