Realization of efficient visual display and radiative cooling thermal emitter with cross-shaped metamaterials

Radiative cooling involves radiating heat into outer space through the atmospheric transparency window without energy consumption. However, the maximum cooling power will inevitably lead to the white color, which does not comply with the visual requirements and greatly hinders its application in color display. In this work, we have designed a novel colored radiative cooling emitter by depositing cross-shaped metamaterials on metal-insulator-metal (MIM). The top structure achieves an average emissivity of 95.6% in the atmospheric window and the bottom layer emits visible light to display a specific color. The adjustable visual display can be obtained with different thickness of the insulator layer. Controllable high emissivity can further be achieved with different incident angle in both TE and TM mode. Based on its unique cooling capacity and color display behavior, the logo of Zhengzhou University is well displayed with our colored radiative cooler. Compared with the traditional radiative cooler, this design has both esthetic and cooling advantages, and it has a broad prospect in various fields such as energy saving, cooling and color display.