A comparative study on humidity response of graphene oxide with reduced graphene oxide and its multifunctional applications

• Published in: Materials research bulletin 2024-12, Vol.180, p.113037, Article 113037
• Main Authors: Kumari, Parvesh, Kumar, Ankit, Sabri, Ylias, Ippolito, Samuel J., Gupta, Gaurav, Shivagan, D.D., Bapna, Komal
• Format: Article
• Language: English
• Subjects: Breath monitoring; Contactless skin sensing; Humidity sensor; rGO; Speech recognition
• ISSN: 0025-5408
• DOI: 10.1016/j.materresbull.2024.113037

•Comparative study between GO and chemically reduced rGO based resistive type humidity sensors.•GO shows superior sensing properties with high sensitivity, small hysteresis, long stability, and quick response.•GO sensor demonstrated the real-time respiratory monitoring, apnea, non-contact skin moisture sensing and speech recognition capabilities.•GO represents a potential candidate for wearable, non-contact health monitoring and human-machine interactive platforms. In this paper, we present a comparative study of Graphene Oxide (GO) and chemically reduced Graphene Oxide (rGO) based resistive type humidity sensors fabricated on Ti/Au Inter-Digital Electrodes (IDEs) coated SiO2 substrates. The sensing performance, including sensitivity, response/recovery time, and hysteresis has been evaluated for both sensors. The GO film exhibited quick response (0.3 s) and high sensitivity (104.7 kΩ/%RH) with remarkable repeatability and negligible hysteresis as compared to rGO film sensor. The excellent humidity sensing properties of GO are attributed to the presence of abundant oxygen-containing polar functional groups on GO relative to rGO. To demonstrate the multifunctional applications of developed GO based sensor, we have also demonstrated its use as respiratory monitoring, non-contact proximity detector, and speech event detector through the detection of humidity perturbations. The work suggests GO sensitive material has high potential for the development of wearable and integrated health monitoring platforms and non-contact sensing devices. [Display omitted]