A Poly(3,4‐ethylenedioxypyrrole)–Au@WO3‐Based Electrochromic Pseudocapacitor

AbstractA poly(3,4‐ethylenedioxypyrrole)–gold nanoparticle (Au)–tungsten oxide (PEDOP–Au@WO3) electrochromic supercapacitor electrode capable of optically modulating solar energy while simultaneously storing/releasing energy (in the form of charge) was fabricated for the first time. WO3 fibers, 50 to 200 nm long and 20 to 60 nm wide, were synthesized by a hydrothermal route and were electrophoretically deposited on a conducting substrate. Au nanoparticles and PEDOP were coated over WO3 to yield the PEDOP–Au@WO3 hybrid electrode. The inclusion of Au in the hybrid was confirmed by X‐ray diffraction, Raman spectroscopy, and energy‐dispersive X‐ray analyses. The nanoscale electronic conductivity, coloration efficiency, and transmission contrast of the hybrid were found to be significantly greater than those of pristine WO3 and PEDOP. The hybrid showed a high specific discharge capacitance of 130 F g−1 during coloration, which was four and ten times greater than the capacitance achieved in WO3 or PEDOP, respectively. We also demonstrate the ability of the PEDOP–Au@WO3 hybrid, relative to pristine PEDOP, to perform as a superior counter electrode in a solar cell, which is attributed to a higher work function. The capacitance and redox switching capability of the hybrid decreases insignificantly with cycling, thus establishing the viability of this multifunction hybrid for next‐generation sustainable devices such as electrochromic psuedocapacitors because it can concurrently conserve and store energy.