Scalable and Tunable PEDOT:PSS Emitter for Thermal Camouflage

Abstract Materials with tunable infrared emissivity are scarce but significant for thermal camouflage. In this study, the optical properties of the conjugated polymer PEDOT:PSS are investigated, and it is found that its infrared emissivity can be facilely modulated by regulating the PSS doping level in PEDOT:PSS, which enables superior thermal camouflage across broad application scenarios with different objects and background temperatures. An effective model with PEDOT particles embedded in the PSS matrix is proposed to elucidate the infrared optical response of PEDOT:PSS thick films. The PEDOT molecules possess strong electromagnetic shielding in the middle‐infrared wavelength range, contributing largely to the metallic infrared optical performance. Moreover, the metallic infrared optical properties of PEDOT:PSS become weaker through increasing the PSS doping level in PEDOT:PSS, resulting in an incredibly large infrared radiation modulation from IR “white” (high reflectivity) to IR “black” (large emissivity ε). Furthermore, the perfect thermal camouflage matched with the environment (εBG ≈75%) can be achieved for the PEDOT:PSS with a large PSS doping level across a wide temperature ranges from 35 to 60 °C. This work not only reveals the IR optical characteristics of PEDOT:PSS via the effective model but also paves the way for scalable thermal camouflage compatible with various application environments.