Construction Of Organic Field Effect Transistors And Applications In Gas Sensing

As an important branch of organic electronics,OFET(Organic field effect transistor)has attracted a large number of researchers.After decades of development,their electrical properties are getting higher and higher,and are widely used in various fields.OFET gas sensors is a prominent field in the application of OFET.Researchers are committed to developing OFET gas sensors with high sensitivity,excellent selectivity,good repeatability and high temperature resistance.This thesis provides a new idea for the construction of OFET gas sensor from the perspective of device structure and semiconductor material design.There are two main works in this thesis:1.In order to prepare OFET-based sensors by low-cost solution method and improve the sensing ability of polymer OFETs to hydrogen sulfide(H2S),a n-type small molecule dicyanomethylene-terminated quinoid compound(TFT-CN)was blended with P3HT and used as the semiconductor active layer.The introducing of TFT-CN into two-component OFET based sensors greatly improves the sensitivity and selectivity for H2S gas and reduces the limit of detection to 10 ppb level due to the strong binding energy between TFT-CN and H2S.The blending ratio has a great influence on the sensing performance and the sensors show the highest sensitivity for various concentrations of H2S when the ratio of TFT-CN:P3HT is 1:6 in weight,and the sensitivity can be increased five times than that of the pure P3HT-based sensors.This work proves that it is a simple,effective and low-cost solution method to improve the sensing performance of OFET-based sensors by introducing a functional molecule into conventional polymers which will inspire the performance improvement and application expansion of many traditional materials.2.Organic semiconductor materials(ICZ-BF and ICZ-BT)based on indocarbazole(ICZ)derivatives were designed,and their performance of field-effect transistors and their application in gas sensors were explored.According to simulation calculations,compared with ICZ-BT,ICZ-BF has a smaller dihedral angle and a more orderly molecular arrangement,which is attributed to the hydrogen bonding in ICZ-BF,which brings the distortion degree between molecules closer.OFET based on ICZ derivatives was prepared and its performance was tested,and the performance of ICZ-BF was 0.0243 cm2 V-1 s-1,while ICZ-BT had no performance.Then,the sensing performance of the OFET gas sensor based on ICZ-BF material on H2S was tested,and the results showed that the OFET gas sensor had obvious response to H2S and excellent selectivity.