Daytime radiative cooling is an eco-friendly, temperature-cooling mechanism that uses the inherent properties of a material without energy consumption. To realize a high daytime radiative cooling ability, it is necessary to minimize light absorption in the solar spectrum (0.3–2.5 μm) and maximize the emissivity in the atmospheric transmittance window (8–13 μm). Currently, the solar reflective layer of a radiative cooling material has the limitation of absorbing UV light, which can reduce the cooling performance. We attempted to solve this problem via UV-to-visible wavelength conversion using CdSe/ZnS giant core-shell structures. By applying this strategy, a wavelength conversion-type radiative cooling emitter (WC-RCE) was fabricated using “giant” CdSe/ZnS core-shell nanocrystals embedded into a polymeric membrane to establish minimized absorption within the UV and short-visible regions, which constitute up to 17.28% of the total solar spectrum. The applied g-NCs have a high photoluminescence quantum yield and a large Stokes shift, and can resolve the absorption in reflective layers, such as silver, by re-emitting the wavelength of the absorbed UV rays into the visible region. Compared with a conventional RCE, the WC-RCE achieves further cooling by 0.38 °C on average from outdoor measurements. Thus, a wavelength conversion strategy was confirmed for efficient daytime radiative cooling.

日间辐射冷却是一种环保的温度冷却机制，它利用材料的固有特性而无需能耗。为了实现高白天辐射冷却能力，有必要最大限度地减少太阳光谱（0.3-2.5 μm）中的光吸收，并最大限度地提高大气透射窗口（8-13 μm）中的发射率。目前，辐射散热材料的太阳反射层具有吸收紫外线的局限性，这会降低散热性能。我们试图通过使用 CdSe/ZnS 巨型核壳结构的紫外到可见光波长转换来解决这个问题。通过应用这个策略，波长转换型辐射冷却发射器 (WC-RCE) 使用嵌入聚合物膜中的“巨型”CdSe/ZnS 核壳纳米晶体制造，以最大限度地减少紫外线和短可见光区域内的吸收，吸收率高达 17.28%的总太阳光谱。应用的 g-NCs 具有高光致发光量子产率和大斯托克斯位移，并且可以通过将吸收的紫外线的波长重新发射到可见光区来解决反射层（如银）中的吸收。与传统的 RCE 相比，WC-RCE 的室外测量结果平均可进一步冷却 0.38 °C。因此，波长转换策略被确认为有效的白天辐射冷却。应用的 g-NCs 具有高光致发光量子产率和大斯托克斯位移，并且可以通过将吸收的紫外线的波长重新发射到可见光区来解决反射层（如银）中的吸收。与传统的 RCE 相比，WC-RCE 的室外测量结果平均可进一步冷却 0.38 °C。因此，波长转换策略被确认为有效的白天辐射冷却。应用的 g-NCs 具有高光致发光量子产率和大斯托克斯位移，并且可以通过将吸收的紫外线的波长重新发射到可见光区来解决反射层（如银）中的吸收。与传统的 RCE 相比，WC-RCE 的室外测量结果平均可进一步冷却 0.38 °C。因此，波长转换策略被确认为有效的白天辐射冷却。