Research On Flexible Hydrogen Sensor Based On PDMS Film

With the progress of society and the development of the times,clean and renewable energy,which can effectively solve many energy and environmental problems,plays a vital role in the future.Faced with the increasing importance of hydrogen energy,hydrogen sensors that can effectively solves the safety problems in the production,transportation and use of hydrogen energy are very important.Graphene is a twodimensional material with great potential in the field of gas sensor research because of its material specificity,and its excellent performance in improving the performance of gas sensors.At the same time,palladium(Pd)is widely used in the research of hydrogen sensors because of its strong hydrogen absorption capacity.Coupled with the increasing urgent demand for flexible devices,the research of flexible hydrogen sensor has a great significance.This thesis focuses on the research of the preparation and testing of flexible hydrogen sensors.The specific content is as follows:First,we studied the best process for preparing graphene film by spraying method and anodized aluminum oxide(AAO)by secondary oxidation.Then,a uniform graphene film was prepared on the flat glass,and the effect of the graphene film thickness on its hydrogen-sensitive characteristics was studied.Then we replaced the flat glass with the AAO substrate and completed the preparation of the hydrogen sensor in the same process.The results prove that the AAO improves the contact area of the device and increase the passage of hydrogen escape,thereby improving the hydrogen sensitivity of the graphene film.At a hydrogen concentration of 1.5%: sensitivity is 1.52%,response time is 37 s,recovery time is 72 s.Subsequently,we combined graphene with palladium to continue the research of hydrogen sensors.In the preparation process of the metal film,we chose two methods : DC magnetron sputtering and liquid phase chemical reduction method to prepare palladium metal film on the graphene film.Compared with the liquid-phase chemical reduction method,the palladium film prepared by the DC magnetron sputtering method is more uniform and can be better used in the preparation of devices.After completing the preparation and testing of the graphene-palladium hydrogen sensor on the hard substrate,we took advantage of the excellent replication function of flexible polydimethylsiloxane(PDMS)materials to prepare hydrogen sensors.We have used flat glass,AAO,and frosted glass as templates to prepare PDMS flexible substrates with different micro-surface deconstructions.Then we completed the preparation of PDMSbased flexible hydrogen sensors and analysis the device performance.Finally,the flexible hydrogen sensor prepared with AAO as a template has better hydrogen sensitivity.When the hydrogen concentration is 2%,the sensitivity reaches is 12.5%,the response time is 20 s,and the recovery time is 60 s.At the same time,the device has a good repeatability.