Long-Range Supramolecular Assembly of a Pyrene-Derivatized Polythiophene/MWCNT Hybrid for Resilient Flexible...

Organic electrochromic polymers hold great potential for integration into low-power flexible electrochromic displays (F-ECDs) due to their wide range of colors and simple processing. However, challenges such as inefficient charge transfer and degradation upon device integration hinder their practical applications. Herein, we report an innovative, general approach that utilizes template-induced supramolecular nanostructuring to engineer established electrochromic polymers, enhancing their performance and durability. We modified a well-known, albeit underperforming in F-ECDs, poly-thiophene polymer (ECP Orange; PT) by incorporating a pyrene appendage, resulting in a copolymer (PTPy) capable of undergoing large-scale assembly in the presence of multi-walled carbon nanotubes (MWCNTs), driven by the establishment of π-π interactions between the pyrene and the MWCNTs (PTPy/MWCNTs). F-ECDs based on these hybrids, produced by spray coating, exhibit improved color switching speeds (t ₉₀ ^OX = 3.6 s, t ₉₀ ^RED = 0.3 s) compared to those of the PT polymer (t ₉₀ ^OX = 53.2 s, t ₉₀ ^RED = 2.5 s). Additionally, PTPy/MWCNTs F-ECDs demonstrate longer cyclability (half-life based on ΔE, ΔE _50% = 17.6k cycles) compared to PT (ΔE _50% = 278 cycles), also when blended with MWCNTs (ΔE _50% = 282 cycles). This work highlights the pivotal role of engineered supramolecular nanostructuring in boosting the performance of organic electrochromic materials, making them suitable for F-ECD scalable commercial applications.