Berquist Zachary J, Turaczy Kevin K, Lenert Andrej
Department of Chemical Engineering, University of Michigan, 2800 Plymouth Road, NCRC B28, Ann Arbor, Michigan 48109, United States.
ACS Nano. 2020 Oct 27;14(10):12605-12613. doi: 10.1021/acsnano.0c04982. Epub 2020 Sep 15.
The greenhouse effect arises when thermal radiation is forced to undergo absorption and re-emission many times before escaping, while sunlight transmits largely unimpeded. Although this effect is responsible for global warming, it is generally weak in solid-state materials because radiation can be easily overpowered by other modes of heat transfer. Here, we report on the use of infrared plasmonic nanoparticles to enhance the greenhouse effect in transparent mesoporous materials. Local surface plasmon resonances in transparent conducting oxide nanoparticles (TCO NPs) selectively shorten the mean free path of thermal photons while maintaining high solar transmittance. The addition of a small amount of TCO NPs (<0.1% by volume) nearly halves the heat losses at 700 °C. This leads to an experimentally demonstrated effective thermal emittance of ∼0.17 at 700 °C, which is the lowest reported value to date, among all selective surfaces and transparent insulating materials measured at 650 °C or above. Our results show that plasmon-enhanced greenhouse selectivity (PEGS) is a promising mechanism for spectral control of radiative heat transfer, and more specifically, for conversion of minimally concentrated sunlight into high-temperature heat.
当热辐射在逃逸前被迫多次经历吸收和重新发射，而阳光在很大程度上不受阻碍地透射时，就会产生温室效应。尽管这种效应导致了全球变暖，但在固态材料中它通常较弱，因为辐射很容易被其他传热方式所压制。在此，我们报告了利用红外等离子体纳米颗粒来增强透明介孔材料中的温室效应。透明导电氧化物纳米颗粒（TCO NPs）中的局域表面等离子体共振选择性地缩短了热光子的平均自由程，同时保持了高太阳透射率。添加少量的TCO NPs（体积分数<0.1%）可使700℃时的热损失几乎减半。这导致在700℃时实验证明的有效热发射率约为0.17，这是在650℃或以上测量的所有选择性表面和透明绝缘材料中迄今为止报道的最低值。我们的结果表明，等离子体增强温室选择性（PEGS）是一种用于辐射传热光谱控制的有前景的机制，更具体地说，是用于将最低浓度的太阳光转化为高温热的机制。
