Abstract Application of highly absorptive construction materials is proved to be one of leading causes of urban overheating in big cities. To avoid the excessive heat by the conventional construction materials, several advanced heat-rejecting coating technologies were developed during the last decades. The main idea behind heat-rejecting coatings is to have colder coatings with the same appearance and colour of conventional coatings. One of the existing technologies for heat-rejecting coatings are advanced coatings with high solar reflection in the infrared range or so-called cool coatings. Recently, re-emission of the visible-range light by nano-scale semiconductors, known as Quantum Dots (QDs), were introduced as another effective heat-rejecting technology. In this paper, we showed that QDs also demonstrate a very high solar transmission in the near-infrared range, and therefore, a highly near-infrared reflective base layer can significantly improve their cooling potential. The high transmission value in the near-infrared range is due to the low absorption coefficient in the wavelengths longer than absorption edge wavelength (i.e. the wavelength corresponding to the bandgap energy) in semiconductors. We show that surface temperature reduction potential of CdSe/ZnS QDs film through fluorescent cooling is about 2.5 °C, which could be increased by another 8.1 °C with a highly near-infrared reflective base layer in a typical sunny day.

中文翻译：

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关于量子点与近红外反射底涂层的结合，以最大限度地发挥其缓解城市过热的潜力

摘要 高吸水性建筑材料的应用已被证明是大城市城市过热的主要原因之一。为了避免传统建筑材料的过热，在过去的几十年中开发了几种先进的排热涂层技术。隔热涂层背后的主要思想是具有与传统涂层相同的外观和颜色的较冷涂层。现有的散热涂层技术之一是在红外范围内具有高太阳反射率的先进涂层或所谓的冷涂层。最近，被称为量子点 (QD) 的纳米级半导体重新发射可见光范围的光被引入作为另一种有效的散热技术。在本文中，我们发现 QD 在近红外范围内也表现出非常高的太阳能透射率，因此，高度近红外反射基层可以显着提高其冷却潜力。在近红外范围内的高透射值是由于在半导体中长于吸收边缘波长（即对应于带隙能量的波长）的波长中的低吸收系数。我们表明，通过荧光冷却 CdSe/ZnS QDs 薄膜的表面温度降低电位约为 2.5°C，在典型的晴天，如果具有高度近红外反射基层，则可以再增加 8.1°C。在近红外范围内的高透射值是由于在半导体中长于吸收边缘波长（即对应于带隙能量的波长）的波长中的低吸收系数。我们表明，通过荧光冷却 CdSe/ZnS QDs 薄膜的表面温度降低电位约为 2.5°C，在典型的晴天，如果具有高度近红外反射基层，则可以再增加 8.1°C。在近红外范围内的高透射值是由于在半导体中长于吸收边缘波长（即对应于带隙能量的波长）的波长中的低吸收系数。我们表明，通过荧光冷却 CdSe/ZnS QDs 薄膜的表面温度降低电位约为 2.5°C，在典型的晴天，如果具有高度近红外反射基层，则可以再增加 8.1°C。