Gas identification with graphene plasmons

Hai Hu,Qing Dai,Xiangdong Guo,Kaveh Khaliji,F Javier García De Abajo,Sudipta Romen Biswas,Tony Low,Zhipei Sun,Xiaoxia Yang

doi:10.1038/s41467-019-09008-0

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 SO2, NO2, N2O, 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 μm2, 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.

Highlights

Identification of gas molecules plays a key role a wide range of applications extending from healthcare to security
Our theoretical analysis reveals that the adsorbed gas-molecule layer on the graphene structure, in conjunction with the strong field confinement associated with the plasmons, is critical for effectively detecting and identifying gas molecules
We successfully demonstrated label-free identification of the gases NO2, N2O, NO, and SO2 using graphene plasmons

Summary

Introduction

Identification of gas molecules plays a key role a wide range of applications extending from healthcare to security. The rotational-vibrational modes of the gas molecules NO2, N2O, NO, and SO2, which are generally important in environmental and military monitoring applications, as well as in medical diagnostics, are unambiguously detected and identified using the designed graphene nanostructures. This result relies on the adsorptive redistribution of the gas molecules on the graphene surface (equivalent to amplifying the gas concentration), facilitating the interaction between ultra-confined graphene plasmons and gas molecules. Our graphene plasmonic sensors successfully perform real-time monitoring of gas molecules during chemical reactions with a fast response time (

Methods

Results

Conclusion