Graphene Coated Dielectric Hierarchical Nanostructures for Highly Sensitive Broadband Infrared Sensing

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-02, Vol.19 (8), p.e2206167-n/a
• Main Authors: Xia‐Hou, Yu‐Jiao, Yu, Yu, Zheng, Jun‐Rong, Yi, Jun, Zhou, Jing, Qin, Ting‐Xiao, You, En‐Ming, Chen, Hai‐Long, Ding, Song‐Yuan, Zhang, Li, Chang, Kai‐Li, Chen, Ke, Moskovits, Martin, Tian, Zhong‐Qun
• Format: Article
• Language: English
• Subjects: Absorption; Broadband; broadband IR absorption; Graphene; graphene‐coated; hierarchical nanostructures; Manganese oxides; Nanostructure; Nanotechnology; Optoelectronics; Organic chemistry; photoresponse; Plasmonics; Surface chemistry; surface‐enhanced IR absorption spectra (SEIRAS)
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202206167

Broadband infrared (IR) absorption is sought after for wide range of applications. Graphene can support IR plasmonic waves tightly bound to its surface, leading to an intensified near‐field. However, the excitation of graphene plasmonic waves usually relies on resonances. Thus, it is still difficult to directly obtain both high near‐field intensity and high absorption rate in ultra‐broad IR band. Herein, a novel method is proposed to directly realize high near‐field intensity in broadband IR band by graphene coated manganous oxide microwires featured hierarchical nanostructures (HNSs‐MnO@Gr MWs) both experimentally and theoretically. Both near‐field intensity and IR absorption of HNSs‐MnO@Gr MWs are enhanced by at least one order of magnitude compared to microwires with smooth surfaces. The results demonstrate that the HNSs‐MnO@Gr MWs support vibrational sensing of small organic molecules, covering the whole fingerprint region and function group region. Compared with the graphene‐flake‐based enhancers, the signal enhancement factors reach a record high of 103. Furthermore, just a single HNSs‐MnO@Gr MW can be constructed to realize sensitively photoresponse with high responsivity (over 3000 V W−1) from near‐IR to mid‐IR. The graphene coated dielectric hierarchical micro/nanoplatform with enhanced near‐field intensity is scalable and can harness for potential applications including spectroscopy, optoelectronics, and sensing. Broadband IR absorption and near‐field enhancement are sought after for wide range of applications. Herein, a novel method is proposed to directly realize high near‐field intensity in broadband IR band by graphene coated dielectric microwires featured hierarchical nanostructures both experimentally and theoretically. The structures show high efficiency broadband IR absorption and play important roles in highly sensitive SEIRAS and photoresponse.