Enhanced electrochromic performance of ordered porous monolayer PBTB film using amine-modified polystyrene spheres as a template

Abstract

Poly(1,4-bis(2- thienyl)-benzene) (PBTB) with a highly ordered porous nanostructure was successfully made using monolayer amine-modified polystyrene (PAS) as template in an electropolymerization method. The ordered porous polymer (OP-PBTB) film obtained can exhibit reversible color changes (yellow and purple) between the doping/dedoping states. Compared with the switching time of pure PBTB (colored time (tc) and bleached time (tb): 1.0 and 3.6 s at 1100 nm; 1.6 and 4.5 s at 620 nm), the switching time of OP-PBTB film is significantly shortened to 0.5 s (tc) and 3.1 s (tb) at 1100 nm, and 0.7 s (tc) and 3.8 s (tb) at 620 nm with the introduction of the porous nanostructure. In addition, the electrochemical impedance spectra (EIS) show that the ordered porous nanostructure offers OP-PBTB film a relatively low charge transfer resistance due to the larger surface area and shorter ion diffusion distance. This leads to higher intercalation/extraction capacities and faster ion diffusion speed, thus further shortening the switching time. Therefore, an effective way to improve the electrochromic performance of conducting polymers may be to construct ordered nanostructures using PAS as a template.