Tunable color display and efficient radiative cooling with metal-insulator-metal spectral modulator

Abstract We present a metal-insulator-metal spectral modulator comprising rhombic Al and diamond unit cells on a Ag layer to achieve efficient colored radiative cooling. The modulator enables tunable color display from light violet to sky blue simply by switching from TE to TM mode. Dynamic chromatic demonstration can be further achieved by varying the aspect ratio of the rhombic unit, the thickness of the diamond layer and polarization angles. With the integration of a top-emitting layer, the spectral modulator attains a net radiative cooling power of 94.33 W m−2 at 300 K. To showcase practical implementation, each letter in the word ‘Zhengzhou’ exhibits distinct color through 10° incremental polarization angle. Overall, our innovative design establishes a framework for advancing energy-efficient cooling, smart color display, and thermal management solutions.