School of Mechanical Engineering , Yonsei University , 50 Yonsei-ro , Seodaemun-gu, Seoul 03722 , Republic of Korea.
The 4th (Energetics and Defense Materials) R&D Institute-3 , Agency for Defense Development , Yuseong P.O. Box 35, Daejeon 305-600 , Republic of Korea.
ACS Appl Mater Interfaces. 2018 Sep 5;10(35):29884-29892. doi: 10.1021/acsami.8b09116. Epub 2018 Aug 27.
Broadband light absorbers are essential components for a variety of applications, including energy harvesting and optoelectronic devices. Thus, the development of a versatile absorbing structure that is applicable in various operating environments is required. In this study, a material-versatile ultrabroadband absorber consisting of metal-coated self-aggregated AlO nanowire bundles with multiscale funnel structures is fabricated. A high absorptance of ∼0.9 over the AM 1.5G spectrum (300-2500 nm) is realized for absorbers with a range of metal coatings, including Al, W, and titanium nitride (TiN). We demonstrate that the plasmonic nanofocusing and index-matching effects of the funnel structure result in strong ultrabroadband absorption for the various metal coatings, even though the coating materials have different optical properties. As an example of applicability in an operating environment, in the evaluation of the thermal-oxidation resistance, the Al-coated solar absorber exhibits superior performance to those coated with refractory materials such as W and TiN because of the protective alumina layer formed on the Al surface.
宽带光吸收体是各种应用的重要组成部分，包括能量收集和光电设备。因此，需要开发一种适用于各种工作环境的多功能吸收结构。在这项研究中，制备了一种由金属包覆的自聚集 AlO 纳米线束和多尺度漏斗结构组成的多功能超宽带吸收体。对于具有各种金属涂层的吸收体，包括 Al、W 和氮化钛 (TiN)，实现了在 AM 1.5G 光谱（300-2500nm）范围内吸收率约为 0.9 的高吸收率。我们证明了漏斗结构的等离子体纳米聚焦和折射率匹配效应导致各种金属涂层产生强烈的超宽带吸收，尽管涂层材料具有不同的光学特性。作为在工作环境中适用性的一个例子，在评估抗热氧化性能时，由于 Al 表面形成的保护性氧化铝层，Al 涂层的太阳能吸收器表现出优于 W 和 TiN 等难熔材料涂层的性能。
