Wyss Roman M, Parzefall Markus, Schlichting Karl-Philipp, Gruber Cynthia M, Busschaert Sebastian, Lightner Carin Rae, Lörtscher Emanuel, Novotny Lukas, Heeg Sebastian
Soft Materials Department of Materials, ETH Zürich, Zürich CH-8093, Switzerland.
Photonics Laboratory, ETH Zürich, Zürich CH-8093, Switzerland.
ACS Appl Mater Interfaces. 2022 Apr 13;14(14):16558-16567. doi: 10.1021/acsami.2c02608. Epub 2022 Mar 30.
Surface-enhanced Raman spectroscopy (SERS) demands reliable, high-enhancement substrates in order to be used in different fields of application. Here we introduce freestanding porous gold membranes (PAuM) as easy-to-produce, scalable, mechanically stable, and effective SERS substrates. We fabricate large-scale sub-30 nm thick PAuM that form freestanding membranes with varying morphologies depending on the nominal gold thickness. These PAuM are mechanically stable for pressures up to more than 3 bar and exhibit surface-enhanced Raman scattering with local enhancement factors from 10 to 10, which we demonstrate by wavelength-dependent and spatially resolved Raman measurements using graphene as a local Raman probe. Numerical simulations reveal that the enhancement arises from individual, nanoscale pores in the membrane acting as optical slot antennas. Our PAuM are mechanically stable, provide robust SERS enhancement for excitation power densities up to 10 W cm, and may find use as a building block in SERS-based sensing applications.
表面增强拉曼光谱（SERS）需要可靠的、高增强的基底才能应用于不同领域。在此，我们介绍了独立式多孔金膜（PAuM），它是易于制备、可扩展、机械稳定且有效的SERS基底。我们制备了大规模的厚度小于30nm的PAuM，其形成的独立式膜具有取决于标称金厚度的不同形态。这些PAuM在压力高达3巴以上时仍保持机械稳定，并表现出表面增强拉曼散射，局部增强因子为10至10，我们通过使用石墨烯作为局部拉曼探针的波长相关和空间分辨拉曼测量来证明这一点。数值模拟表明，增强源于膜中充当光学狭缝天线的单个纳米级孔隙。我们的PAuM机械稳定，在高达10W/cm的激发功率密度下提供强大的SERS增强，并且可能在基于SERS的传感应用中用作构建模块。
