石墨烯
紫外线
发射率
波长
材料科学
红外线的
光电子学
纳米技术
光学
物理
作者
Anirudh Krishna,Jin Myung Kim,Juyoung Leem,Michael Cai Wang,SungWoo Nam,Jae-Ho Lee
出处
期刊:Nano Letters
[American Chemical Society]
日期:2019-06-28
卷期号:19 (8): 5086-5092
被引量:48
标识
DOI:10.1021/acs.nanolett.9b01358
摘要
Spectral emissivity control is critical for optical and thermal management in the ambient environment because solar irradiance and atmospheric transmissions occur at distinct wavelength regions. For instance, selective emitters with low emissivity in the solar spectrum but high emissivity in the mid-infrared can lead to significant radiative cooling. Ambient variations require not only spectral control but also a mechanism to adjust the emissivity. However, most selective emitters are fixed to specific wavelength ranges and lack dynamic control mechanisms. Here we show ultraviolet to mid-infrared emissivity control by mechanically reconfiguring graphene, in which stretching and releasing induce dynamic topographic changes. We fabricate crumpled graphene with pitches ranging from 40 nm to 10 μm using deformable substrates. Our measurements and computations show that 140 nm-pitch crumpled graphene offers ultraviolet emissivity control in 200–300 nm wavelengths whereas 10 μm-pitch crumpled graphene offers mid-infrared emissivity control in 7–19 μm wavelengths. Significant emissivity changes arise from interference induced by the periodic topography and selective transmissivity reductions. Dynamic stretching and releasing of 140 nm and 10 μm pitch crumpled graphene show reversible emissivity peak changes at 250 nm and at 9.9 μm wavelengths, respectively. This work demonstrates the unique potential of crumpled graphene as a reconfigurable optical and thermal management platform.
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