Gas identification with graphene plasmons.

Hu, Hai; Yang, Xiaoxia; Guo, Xiangdong; Khaliji, Kaveh; Biswas, Sudipta Romen; García de Abajo, F Javier; Low, Tony; Sun, Zhipei et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

Identification of gas molecules plays a key role a wide range of applications extending from healthcare to security. However, the most widely used gas nano-sensors are based on electrical approaches or refractive index sensing, which typically are unable to identify molecular species. Here, we report label-free identification of gas molecules SO<sub>2</sub>, NO<sub>2</sub>, N<sub>2</sub>O, and NO by detecting their rotational-vibrational modes using graphene plasmon. The detected signal corresponds to a gas molecule layer adsorbed on the graphene surface with a concentration of 800 zeptomole per μm<sup>2</sup>, which is made possible by the strong field confinement of graphene plasmons and high physisorption of gas molecules on the graphene nanoribbons. We further demonstrate a fast response time (<1 min) of our devices, which enables real-time monitoring of gaseous chemical reactions. The demonstration and understanding of gas molecule identification using graphene plasmonic nanostructures open the door to various emerging applications, including in-breath diagnostics and monitoring of volatile organic compounds.