Performance analysis of thermal cloak with porous silicon structure

Porous materials with micro/nanoscale pore size are widely used in various emerging fields such as thermal insulation outer layer of buildings and personal thermal management devices for their low density, high surface area, and perfect thermal properties. In our previous study, a nanoscale thermal cloak was constructed by a porous silicon structure and its cloaking performance was explored by the ratio of thermal cloaking. However, the effects of factors such as void ratio and dynamic temperature on the cloaking efficiency have not been explored. Therefore, in this work, by fixing the void ratio of the functional region and changing the void ratio of the minimum cell, three nanoscale thermal cloaks are constructed. Their cloaking effects at constant and dy-namic temperatures are explored using perfect silicon thin films as a comparison. Cloaking can be produced at both temperature boundaries, and the smaller the minimum cell void ratio, the better the cloaking effect. Finally, the mechanism of the effect of the void ratio on the cloaking effect is explained by the phonon localization theory, and the smaller the minimum cell void ratio, the stronger the phonon localization. Our research can promote the development of nanoscale thermal cloaks and the engineering application of porous materials.