Self-Switching Dynamic Infrared Radiative Cooler Enabling Triple-Mode Temperature Regulation.

Abstract

Passive radiative cooling offers zero-energy heat dissipation, yet static photonic structures fail in multi-scenario applications due to distinct or even incompatible requirements of infrared emission spectra across different thermal environments. Herein, a self-switching dynamic infrared radiative cooler (DIRC) is proposed that achieves triple-mode temperature regulation, including sub-ambient, near-ambient, and above-ambient cooling application. By leveraging temperature-triggered directional migration of broadband emission water molecules within thermoresponsive hydrogel, the spectral conversion between infrared selective emission for sub-ambient cooling and broadband emission for above-ambient cooling is realized. The resulting DIRC exhibits an average broadband emissivity of 94.1% across 2.5-25 µm and adaptively switches to a selective emissivity of 81.6% within the 8-13 µm, solar reflectivity maintains ≈90% during spectral conversion. The spectral transition is rapid and autonomous, with response times between 85.6 and 37.3 s across 35-45 °C temperature range. Notably, triple-mode thermal-regulated DIRC achieves a sub-ambient cooling of 9.5 °C for building thermal management, near-ambient cooling of 7.0 °C for enhanced personal comfort, and above-ambient cooling of 6.9 °C for photovoltaic panels. By overcoming the single-scenario and weather conditions limitations of static designs, the proposed DIRC represents a versatile strategy for triple-mode thermal regulation across a wide applications.