Colorization strategy for carbon-based electrochromic devices: Achieving visible and mid-infrared regions modulation

Carbon-based materials exhibit unrivaled ability to modulate electromagnetic waves in the infrared band. However, the black appearance restricts the application in the visible light camouflage. This work combines color coatings (consisting mainly of pigments and thermochromic microcapsules) with carbon-based devices and overcomes the high absorption of the color coatings in the mid-infrared band. Ultimately, the obtained white carbon film (W-CNT) device exhibits tunable thermal emissivity from 0.453 to 0.833, maintains a residual modulation range up to 71.7%. In addition, the expansion of the coloration layer to thermochromic microcapsules enables the devices to independently modulate the visible and mid-infrared spectra, further expanding the applicability. We believe that the carbon-based device is valuable for a wide range of applications in camouflage and personal thermal management, which may provide some ideas for designing multispectral independent modulation devices.