In real-world radiative cooling applications, cooling surface temperatures may periodically fluctuate between sub- and above-ambient conditions. Traditional radiative cooling surfaces with ‘static’ spectral properties cannot realize high-efficiency cooling owing to different spectral requirements for different working scenarios. Herein, we report an infrared self-adaptive radiative cooling (ISRC) approach to selectively regulate emission spectra in the range out of the atmospheric window, resulting in a broadband emitter or an atmospheric window-selective emitter. A bilayer structure that consists of an upper microporous SiO₂ fiber layer and a bottom poly(N-isopropylacrylamide) hydrogel layer was developed. Through directional transportation of a broadband emission liquid (i.e., water) in thermo-response hydrogels, the switch of the spectra between selective infrared emissions (∼0.85) under the sub-ambient cooling condition and broadband emissions (∼0.92) under the above-ambient cooling condition was achieved. Improved temperature reductions of ∼4.1 °C (sub-ambient condition) and ∼12.4 °C (above-ambient condition) were measured compared to ‘static’ spectral radiative coolers. In addition, we implemented the simultaneous maximum improvement of daytime photovoltaic (12%) and nighttime thermoelectric (80%) power with the ISRC for round-the-clock electricity generation. The proposed ISRC approach demonstrates a comprehensive way to the efficient use of radiative cooling.

中文翻译：

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低于环境和高于环境的条件：有效利用辐射冷却的综合方法

在现实世界的辐射冷却应用中，冷却表面温度可能会在低于环境条件和高于环境条件之间周期性波动。由于不同工作场景的光谱要求不同，传统的具有“静态”光谱特性的辐射冷却表面无法实现高效冷却。在此，我们报告了一种红外自适应辐射冷却（ISRC）方法，可以选择性地调节大气窗口外范围内的发射光谱，从而产生宽带发射器或大气窗口选择性发射器。开发了由上部微孔SiO ₂纤维层和底部聚( N-异丙基丙烯酰胺)水凝胶层组成的双层结构。通过在热响应水凝胶中定向传输宽带发射液体（即水），光谱在低于环境冷却条件下的选择性红外发射（~0.85）和上述条件下的宽带发射（~0.92）之间切换。达到环境冷却条件。与“静态”光谱辐射冷却器相比，测得温度降低了约 4.1 °C（低于环境条件）和约 12.4 °C（高于环境条件）。此外，我们还与ISRC一起实现了白天光伏（12%）和夜间热电（80%）电力的同步最大提升，实现全天候发电。所提出的 ISRC 方法展示了一种有效利用辐射冷却的综合方法。