Development of flexible gas sensors based on rGO and rGO/ZnO conductive inks for detection of NO2 and NH3

• Grant number: 23/00913-8
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): July 20, 2023
• Effective date (End): July 19, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Valmor Roberto Mastelaro
• Grantee: Amanda Akemy Komorizono
• Supervisor: Eduard Llobet
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Research place: Universitat Rovira i Virgili (URV), Spain
• Associated to the scholarship: 22/03325-7 - Development of flexible gas sensors based on rGO and rGO/ZnO conductive inks for detection of NO2 and NH3, BP.DR

Abstract

The advances of industrialization and urbanization have brought an increase in environmental pollution and with it, an increase in the demand for sensors capable of detecting and monitoring the toxic gases present in the environment in real time. In addition, development of a new generation of electronics that are ultra-light, low-cost, flexible, bendable, and adaptable to the shape of objects, human or robotic bodies, makes it possible to manufacture flexible gas sensors. These flexible sensors can be wearable and allow real-time detection and monitoring of toxic gases. Thus, the objective of this work is the development of flexible gas sensors based on reduced graphene oxide (rGO) and rGO/ZnO for the detection and monitoring of NO2 and NH3 toxic gases. Graphene oxide (GO) will be synthesized by the modified Hummers method and chemically reduced with sodium borohydride. The ZnO nanoparticles will be synthesized by the method of polymeric precursors - Pechini. The inks will be formulated based on conductive materials, rGO and ZnO, distilled water as a solvent and sodium carboxymethyl cellulose (CMC) as a binder. Conductive inks will be printed on paper, PI and PET substrates by screen printing and inkjet printing techniques. The GO, rGO, ZnO and the conductive inks will be characterized by X-ray diffraction, Raman spectroscopy, X-ray excited photoelectron spectroscopy (XPS) and electron microscopy. The viscosity of conductive inks will also be analyzed to formulate inks within the viscosity range suitable for the screen-printing technique. The electrical resistance of the conductive tracks before and after several bending cycles will be analyzed by the four-prong method. Detection measurements of NO2 and NH3 gases will be performed with the sensors before and after bending to evaluate the application os these materials as flexible gas sensors. In addition to the detection of NO2 and NH3 gases, a study of the selectivity of the sensors will be carried out (ethanol, hydrogen, carbon monoxide, VOCs and ambient humidity). (AU)