Broadband Radiative Cooling and Decoration for Passively Dissipated Portable Electronic Devices by Aperiodic Photonic Multilayers

Abstract

Broadband radiative cooling and decoration for passively dissipated portable electronic devices by an aperiodic photonic multilayer structure is proposed theoretically. The designed optical structure can strongly emit in the infrared region from 6.9 to 40 µm within the blackbody radiation spectrum of electronic devices. Its emission spectrum exhibits good uniformity across different incident angles, enhancing the cooling performance. At an ambient temperature of 20 • C, the designed broadband radiative cooler can produce a net cooling power of 46.88 W m −2 , 65.95% higher than pure silica of the same thickness. At a typical junction temperature of 90 • C allowed by the microprocessor die, the net cooling power reaches 239.55 W m −2 , still with an 18.21% improvement over pure silica glass. In the visible regime, the designed structure displays a low uniformity in the reflection spectrum, producing an elegant color shift from the translucent gray color of normal direction to the silver and highly reflective look at a grazing angle. These results can be useful in future exterior and thermal designs of portable electronic devices.

Highly efficient flexible structured metasurface by roll-to-roll printing for diurnal radiative cooling

“…Radiative cooling effects have been successfully demonstrated in three distinct types based on the used materials and structural engineering strategies: polymers [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], multilayer thin films [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], and metamaterials [40][41][42][43][44][45][46][47][48][49]. Among these designs, polymer films have shown many attractive features, such as low solar absorption, relatively high emissivity in the atmospheric transparency windows, low cost, and scalability, which make them very promising for real-life applications.…”