Conference Agenda

On the tenth anniversary of the first demonstration of daytime radiative cooling, we will both provide an introduction to, and survey, the state of the field, highlighting the role of advanced in optical and nanoscale materials in enabling recent progress. We will also look ahead to new frontiers and challenges in radiative cooling materials and technological applications enabled by radiative cooling.

Self-adaptive thermoregulation, the mechanism living organisms use to balance their temperature, holds great promise for decarbonizing cooling and heating processes. This functionality can be effectively emulated by engineering the thermal emissivity of materials to adapt to background temperature variations. Yet, solutions that marry large emissivity switching (Δϵ) with scalability, cost-effectiveness and design freedom are still lacking. Here, we fill this gap by introducing infrared dipole antennas made of tuneable thermochromic materials. We demonstrate that non-spherical antennas (e.g. nanorods) made of vanadium-dioxide can exhibit a massive (~200-fold) increase in their absorption cross-section as temperature rises. Embedding these antennas in polymer films, or simply spraying them directly, creates free-form thermoregulation composites, featuring an outstanding Δϵ~0.6 in spectral ranges that can be tuned at will. Our research paves the way for versatile self-adaptive heat management solutions (coatings, fibers, membranes, and films) that could find application in radiative-cooling, heat-sensing, thermal-camouflage, and other.

Radiative cooling involves decreasing the temperature of a body by emitting infrared radiation. When the heat loss from the emitting surface exceeds the heat gain, e.g., from the sun or the atmosphere, a passive net cooling effect occurs without the need for electricity or other power sources. Integrating radiative cooling materials with other renewable energy technologies represents a promising frontier in sustainable energy systems. In this study, we explore the strategic utilization of the net cooling effect resulting from radiative cooling materials to enhance the efficiency of photovoltaic panels, as they are susceptible to performance degradation with temperature variations. Our investigation focuses on the integration of these materials with photovoltaic cells and explores the possibility of integrating them in to other renewable energy technologies such as thermoelectric generators, addressing critical challenges, including thermal management, efficiency optimization and operational stability.

We present preliminary results on the fabrication of patterned surfaces by Direct Laser Interference Patterning and the characterization and theoretical interpretation of their infrared emissivities. The upgraded experimental method is capable of studying the full directional emission of samples under a controlled atmosphere at high temperatures. The effects of surface patterning can be quantitatively studied and modeled using a numerical method based on rigorous coupled-wave analysis (RCWA), a technique usually employed for periodic surfaces. The results show that laser interference patterning is capable of modifying the infrared emission of metallic materials, and that these changes can be accurately measured and numerically reproduced.