Broadband and Wide-Temperature-Range Thermal Emitter with Super-Hydrophobicity Based on Oxidized High-Entropy Film

This paper demonstrates a broadband and wide-temperature-range thermal emitter with super-hydrophobicity based on an oxidized high-entropy film. The annealed (NiCuCrFeSi)O high-entropy film can serve as a mid-infrared emitter due to its three characteristics: (i) high blackbody-like emission in a broadband mid-infrared region from 2.5 to 20 μm; (ii) high emittance (more than 90%) in a wide temperature range from 300 to 1000 K; (iii) super-hydrophobicity with a high contact angle of 151° and low tilt angle of 5°. These characteristics originate from the recrystallization of the as-deposited film and formation of a cavernous structure with a plethora of nanoscale polyhedrons and holes after an annealing process, supported by the results of XRD and SEM/EDX. This work may provide new ideas for applications of thermal emitters operating at a substantially wide temperature range.