Smart radiative cooling devices based on thermochromic materials such as vanadium dioxide (VO2) are of practical interest for temperature regulation and artificial homeostasis, i.e., maintaining stable equilibrium conditions for survival, both in terrestrial and space applications. In traditional solar reflector configurations, solar absorption in the VO2 layer is a performance limiting factor due to the multiple reflections of sunlight in the stack. Here, we demonstrate a visually transparent, smart radiator panel with reduced solar absorption. An Al-doped ZnO transparent conducting oxide layer acts as a frequency selective infrared back-reflector with high transmission of solar radiation. In this study we make use of high-quality VO2 thin films deposited using atomic layer deposition and optimized annealing process. Patterning of the VO2 layer into a metasurface results in a further reduction of the solar absorption parameter α to around 0.3, while exhibiting a thermal emissivity contrast Δε of 0.26 by exploiting plasmonic enhancement effects. The VO2 metasurface provides a visual spectrum transmission of up to 62%, which is of interest for a range of applications requiring visual transparency. The transparent smart metasurface thermal emitter offers a new approach for thermal management in both space and terrestrial radiative cooling scenarios.

中文翻译：

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具有高视觉透明度的 VO2 超表面智能热发射器，用于空间和地面应用中的被动辐射冷却调节

基于二氧化钒（VO2）等热致变色材料的智能辐射冷却装置2) 对温度调节和人工稳态具有实际意义，即在陆地和太空应用中保持稳定的生存平衡条件。在传统的太阳能反射器配置中，VO 中的太阳能吸收2由于堆栈中阳光的多次反射，层是性能限制因素。在这里，我们展示了一种具有减少太阳能吸收的视觉透明智能散热器面板。Al掺杂的ZnO透明导电氧化物层用作具有高太阳辐射透射率的频率选择性红外背反射器。在这项研究中，我们利用高质量的 VO2使用原子层沉积和优化的退火工艺沉积的薄膜。VO的图案化2层进入超表面导致太阳能吸收参数的进一步降低α到 0.3 左右，同时表现出热发射率对比度 Δε通过利用等离子体增强效应，为 0.26。VO2超表面提供高达 62% 的视觉光谱透射率，这对于需要视觉透明度的一系列应用很有意义。透明的智能超表面热发射器为空间和地面辐射冷却场景中的热管理提供了一种新方法。