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 Al2O3 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.
Bibliographical noteFunding Information:
This research was supported by the Global Research Laboratory (GRL) Program, the Pioneer Research Center Program, a grant from the National Research Foundation (NRF) of Korea funded by the Ministry of Science, ICT & Future Planning (NRF-2016K1A1A2912758, NRF-2013M3C1A3065045), the Center for Advanced Meta-Materials (CAMM-2014M3A6B3063712) funded by the Ministry of Science, ICT and Future Planning as a Global Frontier Project, the Asian Office of Aerospace R&D grant, FA2386-15-1-4024 (15IOA024), and the MRSEC: Soft Materials Research Center funded by the National Science Foundation (DMR-1420736).
All Science Journal Classification (ASJC) codes
- Materials Science(all)