PEDOT:PSS-V2O5 hybrid for color adjustement in electrochromic systems

Electrochromism is known as a modulation of the optical properties under an applied voltage. Used in various applications, aside to the commercialized smart windows based on transmissive electrochromic devices (ECDs), the opaque systems have received significant interest for displays purposes. Herein, in a novel approach to adjust color, electrochromic oxides with high EC performance were chosen as additives to commercialized conductive and electrochromic polymer ink. More precisely opaque films were deposited (using Bar Coater) from mixtures of V2O5, synthesized by polyol process, with poly(3,4-ethylenedioxythiophene, polystyrene sulfonate) PEDOT:PSS commercial ink in different weight percentages (wt%) ranging from 0 to 100 (V2O5 wt%). Films thicknesses varied from hundred of nms to few μms. As-deposited films colors range from blue for PEDOT:PSS to orange for V2O5. PEDOT:PSS-V2O5 films exhibit significant electrochromic properties associated with a good electrochemical stability. In the series, the hybrid film with 90 wt%–10 wt% PEDOT:PSS-V2O5 shows a reversible behavior with significant reflectance modulation (ΔR≈20.5% at 550 nm) in lithium based electrolyte and a good contrast (ΔE∗ > 30). The maximum contrast was reached for 3.7 μm thick layer. Our results indicate that the hybrid film, combining the benefit of mixing inorganic and organic materials, are promising materials for enhancing electrochromic devices color and hybrid electrochromic materials processability on large scale