Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment

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• 作者：Omar Khatib ; Joshua D. Wood ; Alexander S. McLeod ; Michael D. Goldflam ; Martin Wagner ; Gregory L. Damhorst ; Justin C. Koepke ; Gregory P. Doidge ; Aniruddh Rangarajan ; Rashid Bashir ; Eric Pop ; Joseph W. Lyding ; Mark H. Thiemens ; Fritz Keilmann ; D. N. Basov
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：August 25, 2015
• 年：2015
• 卷：9
• 期：8
• 页码：7968-7975
• 全文大小：593K
• ISSN：1936-086X

文摘

Scattering scanning near-field optical microscopy (s-SNOM) has emerged as a powerful nanoscale spectroscopic tool capable of characterizing individual biomacromolecules and molecular materials. However, applications of scattering-based near-field techniques in the infrared (IR) to native biosystems still await a solution of how to implement the required aqueous environment. In this work, we demonstrate an IR-compatible liquid cell architecture that enables near-field imaging and nanospectroscopy by taking advantage of the unique properties of graphene. Large-area graphene acts as an impermeable monolayer barrier that allows for nano-IR inspection of underlying molecular materials in liquid. Here, we use s-SNOM to investigate the tobacco mosaic virus (TMV) in water underneath graphene. We resolve individual virus particles and register the amide I and II bands of TMV at ca. 1520 and 1660 cm<sup>鈥?sup>, respectively, using nanoscale Fourier transform infrared spectroscopy (nano-FTIR). We verify the presence of water in the graphene liquid cell by identifying a spectral feature associated with water absorption at 1610 cm<sup>鈥?sup>.