Ph5T2 Flexible Organic Micro/Nanometer-sized Single-Crystal Field-Effect Transistor Gas Sensor

Traditional gas sensors are based on hard substrates,with the development of society and technology,more and more researchers have focused on flexible,portable and wearable electronic devices.Flexible organic field-effect transistor gas sensor has attracted lots of attention due to the advantages of flexibility,high sensitivity,high stability,light mass,low operating temperature,signal amplification,multi-parameter,etc.However,all reported studies of flexible OFET gas sensors only show the flexibility of the device,and response measurements are performed on a flat supporting layer.In contrast,it is essential to detect the responses of the device in a bent state,as flexible organic device have primary application potential in portable and wearable electronics.Ph5T2 single crystal has attracted much attention in OFET gas sensor research,not only because of its flexibility,ultra-thin and light weight,but also its good chemical and excellent gas sensing properties.The preparation of gas sensor and the gas sensing response test using micro nano single crystal semiconductor material will help to study the response mechanism and provide theoretical guidance for further development and application of flexible gas sensor.We fabricated flexible OFET gas sensors based on configuration of organic field-effect transistor with ultrathin Ph5T2 single-crystal microplate and flexible PET as substrate.The effects of the three different deformations on the gas sensing properties of the gas are studied under the flat,tensile and compressive conditions.The main contents are as follows:1.In this work,we fabricated flexible OFET gas sensors based on ultrathin Ph5T2single-crystal microplates on the flexible PET substrate by the method of mechanical probe transfer.In the air and nitrogen environment,the device transfer curves were tested many times.It is found that can be well coupled,indicating that the device has excellent repeatability and stability,which ensures the reliability of subsequent gas sensing test results.2.Ph5T2 micro/nano single crystal flexible OFET gas sensors were tested under flat,tensile and compressive three different states.The flexible devices exhibited strikingly different sensing behaviors under different deformation states toward H₂S at room temperature.In a tensile state with r=7 mm,the flexible sensor presented an unprecedented response as high as 400%at 1 ppm H₂S,which is almost one order of magnitude higher than the response in a flat state and surpasses all reported flexible H₂S sensors.3.Explore the mechanism of the above results.The tension in the device increases the intermolecular separation between Ph5T2 molecules,during the same time,more gas molecules adsorbed on the conductive channel,which increased the response of the gas.The situation in the compressive state is the opposite.Then the response performances of H₂S,NO₂ and NO gas for single concentration under flat,tensile and compressive three different deformation states were investigated based on Ph5T2 micro/nano single crystal flexible OFET gas sensors to verify the reliability of the experimental results and the correctness of mechanism exploration.