Graphene Nanocomposite Based Flexible Film Sensors

Along with the rapid development of the social economy,people's living standards have been greatly improved.However,the living environment and working environment of people have been seriously damaged,and people's daily life and industrial production of a variety of toxic and harmful gases on human health hazards are increasingly serious.At present,there are some deficiencies such as inferior response,poor selectivity,instability,relatively high operating temperature and inconvenient handing.Graphene is a novel two-dimensional nanomaterial with a single atomic layer,which has a large specific surface area and fast velocity carrier transport performance,and is an ideal and potential new-style sensing material.The sensor based on graphene and its composites improves the response performance,enhances the selectivity,reduces the operating temperature,improves the cycle stability,and has strong machinability.The device volume is greatly reduced,and is suitable for preparing the portable gas sensor.Therefore,the graphene composites have great potential in the preparation of gas sensors,which has become a research hotspot both at home and abroad.In this thesis,because of the gas sensing mechanism of graphene as p-type semiconductors and the research hotspots of flexible sensors at home and abroad,the gas sensing performance of the graphene was improved by combining with other polymer materials or functionalization,and the research on the preparation of flexible and portable gas sensor devices was also carried out.The main contents and results of this paper are listed below:First,in this paper,we developed a flexible,transparent sensing film of rGO/PANI nanocomposite to NH3 gas,which can be integrated into flexible electronic equipments.The conductive polymer PANI was prepared in the reduced graphene oxide acidic solution by in situ polymerization of aniline monomer,meanwhile rGO/PANI nanocomposites concurrently deposition on transparent PET substrate during the polymerized process to form a multilayer nanocomposite sensing film.The flexible sensing film shows outstanding gas sensing performance to ammonia,which the concentrations in the range from 0.1 ppm to 100 ppm,80%or more transparency in the visible region,the response time(36 s)and recovery time(18 s)is short,sensing performance is reliable,in 1000 times the bending and extending cycles test,the gas sensor performance did not decline.This work in the preparation of flexible,transparent gas sensing films and their integration into wearable,flexible electronic equipment has some guiding significance.Second,electrospinning of polyacrylonitrile and loading functionalized graphene detect low concentration of nitrogen dioxide.In this paper a network-like polyacrylonitrile was prepared by electrospinning on the window screen,and a sulfonic group functionalized reduced graphene oxide,sulfonated reduced graphene oxide(SRGO)was fabricated to provide a 3D skeleton structure to form a three-dimensional network-like composite.Greatly improving the gas-sensing properties of NO2,and studied the effect of electrospinning polyacrylonitrile on the sensitivities at different time.