Device parameter optimization of all-organic electrochromic smart windows: Role of performance enhancer metal-oxides

Abstract

Electrochromic devices (ECDs) based smart windows are essential for designing energy-efficient buildings

yet, no single material displays properties that can lead to the improvement in all the device parameters. This study suggests a recipe for optimizing ECD performance through selective doping of various metal oxides. Zinc oxide (ZnO), tungsten trioxide (WO3), titanium dioxide (TiO2), and molybdenum trioxide (MoO3), have been synthesized and used as dopant to improve various aspects of ECD properties of a poly(3-hexylthiophene) (PT) and ethyl viologen (EV) based all-organic ECD. The device doped with highly porous ZnO improves the color contrast (515 nm) with high change in transmittance at NIR region, whereas device doped with WO3 offers high coloration efficiency of more than 1000 cm2/C (515 nm) and fast switching time of ∼0.5 s for both 515 and 750 nm. The all-organic PT-EV ECD doped with TiO2 gives coloration efficiency of 1000 cm2/C at 515 nm along with moderate performance in other parameters, while the doping of MoO3 also offers high change in transmittance at 750 nm for heat filtering property. All the metal oxides show high stability in the NIR region. Selecting the right metal oxide as dopant for improving a specific ECD performance would assist researchers in creating extremely effective ECD for on-field application of these smart electronic curtains. © 2025 Elsevier B.V.