Implementation of high-performance flexible electrochromic device based on polyaniline/ carbon quantum dots

The electrochromic (EC) process is essentially an electrochemical reaction associated with the intercalation (de-intercalation) of ions to (from) the EC film. To improve the infrared emissivity modulation performances of the infrared electrochromic devices (IR-ECDs), polyaniline/carbon quantum dots (PANI/CDs) flexible films were fabricated by the electropolymerized approach in this paper. The prepared PANI/CDs porous films were exhibited and verified excellent electrochromic properties through micromorphology analysis and electrochemical tests. The measured emittance variation (Δ ε ) of the prepared PANI/CDs samples are 0.41, 0.46, and 0.42 in ranges of wavelength 3–5 μm, 8–14 μm, and 2.5–25 μm, respectively. In addition, for the infrared range of 2.5–25 μm, the radiation energy can be continuously modulated from 80.77 to 241.98 W/m 2 (ΔP = 161.21 W/m 2 ). The assembled IR-ECD based on PANI/CDs films obtains excellent IR modulation ability, that the emittance variations are 0.39, 0.41, and 0.37 in the wavelength ranges of 3–5 μm, 8–14 μm, and 2.5–25 μm, respectively. The switching times of the device for the coloration and bleaching are 3.1 s and 3.7 s respectively, much shorter than that of previously reported ECDs based on PANI. Meanwhile, the developed ECD presents decent durability, as the Δε values of IR-ECD in wavelength ranges of 3–5 μm, 8–14 μm, and 2.5–25 μm maintaining radio of 75%, 76%, and 68%, and current maintaining ratio of the device is above 90% after aging measurements of consecutive 100 cycles. Furthermore, the integrated IR-ECD was proposed to achieve dynamic conversion from golden yellow to dark green in the visible light regime through precise tuning of external biasing voltage. The proposed ECD based on PANI/CDs technology is promising for the future of adaptive IR sensors and thermoregulation-related applications.