Study Of The Interfacial Optimization Of Organic Thin-film Transistor Based On The Modification Of PVP Film

Thin film transistor(TFT)is a kind of sensitive electronic components,which has been widely used in flat-panel display,smart card,sensor and other fields.Organic thin film transistors(OTFT)have attracted extensive attention due to their advantages of simple solution-based fabrication,light-weight,and flexibility,which are being developed as next generation of flexible electronic.At the present,although the study of OTFT has made,great progress,the electrical performance and stability of the devices are still needed to be further improved to meet the industrial demand.Therefore,this thesis focused on the improvement of electrical performance and stability of the organic thin film transistor,via modifying surface of dielectric layer with interpenetrating polymer network(IPN)method.This work mainly includes three aspects as follows:1.Spin-coating process was employed to fabricated both Poly(4-vinylphenol)(PVP)dielectric layer and PDVT-8 organic semiconductor layer of OTFT.The surface morphology and surface energy of PVP films were analyzed by atomic force microscopy(AFM)and contact angle measurements.Moreover,a large number of experiments were performed to explore a series of appropriate experimental parameters to obtain stable performance of OTFT devices,such as saturation mobility(>0.1 cm2V-1s-1)and On/Off ratio(>103).2.As the cross-linking process between PVP and the crosslinker could cause pinhole films and nondense net structure of dielectric,IPN method was employed to modify the surface of PVP films.Four kinds of organic liquid monomers were infused into network of PVP films to create an interpenetrating polymer network after photopolymerizatoin,which eliminated pinholes and enhanced densification of PVP based films.Furthermore,we had further investigated the impact of interpenetrating polymer network PVP films on the surface morphology and surface energy of the dielectric layer,crystal size of PDVT-8 organic semiconductor,and electrical properties of OTFT devices.3.As IPN method has successfully improved the performance of organic thin film transistors,interpenetrating polymer network PVP films were applied to the flexible organic thin-film transistors,aiming to improve its stability of the electrical performance under mechanical strain.This work mainly involved two aspects:1.the devices were tested under different bending radius to study the impact of tensile stress on the electrical performance;2.the devices were tested after different times of bending to study the impact of cyclic bending fatigue on the electrical performance.