Super broadband mid-infrared absorbers with ultrathin folded highly-lossy films.
Super broadband mid-infrared absorbers with ultrathin folded highly-lossy films.
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DOI：
10.1016/j.jcis.2022.09.046
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发表时间：
2022-09
影响因子：
9.9
通讯作者：
Heng Zhang;Hao Wu;Xiaowen Li;J. Hao;Qunqing Li;Zhiqiang Guan;Hongxing Xu;Chang Liu
中科院分区：
文献类型：
--
作者：
Heng Zhang;Hao Wu;Xiaowen Li;J. Hao;Qunqing Li;Zhiqiang Guan;Hongxing Xu;Chang Liu
Super broadband optical absorbers with ultrathin films have been keenly pursued for a long time. Although highly lossy materials with sharp light attenuation have the potential to become super absorbers, a large percent of light from free space is inevitably reflected back for the distinct impedance mismatch. Here, a simple strategy, of which reducing the thickness of highly-lossy thin films to minish reflectance and simultaneously folding the ultrathin films to make light multiple pass through, is proposed to obtain super broadband mid-infrared absorbers with ultrathin films. Along this line, the absorbers were prepared by depositing Al-doped ZnO film on scaffolds consisted of alumina spherical shells, whose substrates were opaque. When the thickness of Al-doped ZnO is 43 nm and the layer number of scaffolds is three, a maximum average absorptance was achieved as 97.6% over the wavelength range from 3 to 15 μm. Applying this strategy on polished Al foil, excellent infrared camouflage performance on human-body background was demonstrated. Featured by the strong broadband optical absorption with ultrathin films, flexible access to multiple substrates and low-cost procedures, this approach has the potential in widespread applications of infrared thermal emitters and optoelectronic devices.
