Study On The Effect Of Polymer Blend Active Layer On The Performance And Gas Sensitivity Of OFET

OFET has various advantages such as high integration,flexibility,large area production,and low preparation cost,and is currently being applied more and more widely in the field of gas sensing technology.In the research work of OFET,a single organic material is often used as the gas sensing layer,which will limit its gas sensing response.In this work,polymer blending was used as the active layer and further modification of the dielectric layer was carried out.The effects of polymer blending as the active layer and modification of the dielectric layer on the electrical performance and gas sensitivity of the device were studied.The research content is mainly divided into the following three parts:1.The effect of polymer blending as an active layer on the performance of OFET devices was studied.The active layer of OFET devices was prepared by blending P3HT with poly-TPD in different mass ratios.As the blending ratio of poly-TPD increases,the gas responsiveness of the blending device to NO₂ at 30ppm gradually increases.When the blending ratio of poly-TPD is 80wt.%,The gas responsiveness increased by 5.7 times compared to the unblended device（VG=80V）,and further increased to 6.7 times at a gate voltage of 0V.After the active layer is blended,the electrical performance of the device is adversely affected.2.The effect of adding MoS₂ in the preparation of active layers on the performance of OFET devices was studied.After pure P3HT is added to MoS₂,organic films are induced to form ordered nanofibers,which is conducive to carrier transport,and compared with pure P3HT devices,the mobility reaches 0.0516cm²/Vs,which is 8.4 times higher.The threshold voltage decreased from 16.5V to 6.5 V.The addition of MoS₂ is conducive to the improvement of electrical characteristics,but its responsiveness is comparable to that of MoS₂ without the addition,and it is not helpful in terms of gas sensitization.3.On the basis of active layer blending,different polymer materials（PS,PVA,PMMA）were selected to modify the dielectric layer and study the electrical characteristics and gas sensitivity changes of the device.In terms of electrical characteristics,the devices modified with PS performed the best,with an increase in mobility from 0.0058cm²/Vs unmodified to 0.0357cm²/Vs,and a significant decrease in threshold voltage.PS modification improved the crystallinity of P3HT molecules and facilitated carrier transport.In terms of gas sensitivity,PVA modification has the best effect.Compared to pure P3HT devices,the responsiveness of the blend device is increased by 2.9 times,further achieving a 2.1 times increase.The blend membrane exhibits phase separation,and the PVA hydroxyl group effectively absorbs NO₂ molecules,induces hole generation and providing a large number of hole carriers,thereby improving gas sensing response.