Preparation And Characterization Of OFET Based On Solution Method

With the gradual discovery of new organic-materials and the gradual improvement of manufacturing processes,organic field-effect transistors(OFETs)have begun their rapid development.OFET has been widely used in flexible displays,organic sensors,distributed portable devices and other fields because of its advantages of flexibility,low cost and large area production.As a method for preparing an OFET,the solution method has the advantages of simple operation convenient manufacture,and low requirement for preparation equipment.Optimization of this method will effectively promote the development of OFET.First of all,this article explores the relationship between various solutions and device performance.The P3HT-OFET device was fabricated and studied by pulling,smearing,spin coating and dripping methods.P3HT was used as the active layer material.The correspondence between device performance and film morphology was analyzed.By comparison^the device obtained by spin coating has better performance and its mobility(3.2124×10-3cm2/Vs)is twice that of other methods.Second,the basic processes such as spin coating speed,annealing method,and electrodes were explored.When the P3HT solution was spin-coated at 1400 rpm,annealed in a vacuum oven,and Au was used as a source and drain electrode,the resulting device exhibited better performance and its mobility(7.532×10-3cm/Vs)was improved by 1.3 times compared with that before optomization.Use the optimized parameters to provide reference for subsequent experiments.Then,using PVP-PMP-PGMEA as the dielectric layer solution,based on the optimal parameters of P3HT-OFET,the PVP layer was made by spin coating.By analyzing the electrical characteristics of the device and the morphology of the film,the average grain size increases from 276 nm to 1.154 ?m using PVP as the dielectric layer,which increases the average grain size of semiconductor materials and promotes carrier transport.The mobility of the resulting device(9.318×10-3cm2/Vs)was improved by 24%compared to the device without PVP,indicating that the addition of a PVP layer to the basic device improves the performance of the device.Finally,HMDS was used to modify the surface of SiO2,and the relationship between dielectric layer-semiconductor interface characteristics and device performance was discussed.Based on the optimal parameters of the P3HT-OFET,the HMDS solution was spin-coated at 3500 rpm.By analyzing the electrical characteristics of the device and the film morphology,the average grain size of the obtained film is increased from 276 nm to 408 nm,and the device performance is better.After surface modification,the mobility of the device is 8.866×10-3cm/Vs,an increase of 18%,shows that using HMDS to modify the surface of the dielectric layer can improve device performance.