Antenna array-enhanced attenuated total reflection IR analysis in an aqueous solution. Issue 40 (9th October 2019)

• Record Type: Journal Article
• Authors: Li, Jian; Yan, Zhendong; Li, Jin; Wang, Zhenlin; Morrison, William; Xia, Xing-Hua
• Is Part Of: Nanoscale. Volume 11:Issue 40(2019)
• Page Start: 18543
• Page End: 18549
• Publication Date: 2019-10-09
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr04032c
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We presented a simple approach to the fabrication of large-scale triangle gold antenna array with tunable resonance that can be used as enhanced IR substrate for monitoring interfacial events in an aqueous solution. Abstract : Attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) is a powerful technique that provides structural and functional information during dynamic reactions in aqueous solutions. One existing limitation is the sensitivity to extract the signals of trace-level analytes from the background water in situ and in real time. Here, we proposed a novel ATR-SEIRAS platform that integrated a large-scale triangle gold antenna array onto a conventional ATR-IR platform to increase the sensitivity of this analytical technique. A square centimeter level well-ordered gold antenna array was fabricated onto an Si prism via nanosphere lithography. The size-dependent antenna array resonance had weak correlation with the incident polarization and antenna orientation, allowing antenna array-enhanced IR detection without the requirement of a microscope. In addition, the antenna resonance shift that occurred due to analyte adsorption-induced refractive index variation could be minimized benefiting from the high refractive index of Si (3.4). As a demonstration, we dynamically monitored the adsorption of the trace levels of proteins on top of the antenna array with a real signal enhancement factor larger than 300. Our platform opens an avenue to apply antenna array-enhanced IR spectroscopy in an aqueous environment measured via commercial IR instruments, which is extremely promising for the interfacial applications that require signal enhancement.