Harnessing the spectrum: High-performance infrared electrochromic device with multicolor visibility based on PEDOT:PSS/SWCNT films

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a highly promising electrochromic material for intelligent thermal management due to its intrinsic high conductivity, which enables electro-emissive modulation without additional conductive electrodes. However, practical applications are hindered by incomplete reduction of PEDOT during electrochemical cycling, leading to suboptimal emissivity modulation. Moreover, its monotonic color change in the visible spectrum constrains its functional versatility. To overcome these constraints, we introduce an innovative doping strategy utilizing single-walled carbon nanotubes (SWCNTs), which form a percolating conductive network and enhance charge transfer via π-π interaction-enabled electron delocalization. This synergistic effect promotes more complete reduction of PEDOT, leading to significantly enhanced modulation of thermal emissivity. Furthermore, through the incorporation of functional dyes, we expand the visible color adaptability of the films, achieving reversible transitions between yellow-green and green states. The resulting PEDOT:PSS/SWCNT-based electrochromic devices demonstrate remarkable performance: an emissivity modulation (∆ε) of 0.27 in the 3–5 μm band and 0.35 in the 8–14 μm atmospheric window, rapid switching (2.7 s for both bleaching and coloring), and excellent mechanical and cycling stability. Notably, by implementing an auxiliary silver grid electrode, we successfully scaled the device to 15 × 15 cm 2 , demonstrating a viable route toward large-area applications. This work provides a scalable pathway to high-performance PEDOT-based electrochromic materials and devices, highlighting their potential in advanced thermal management applications.