Study Of The Interfacial Characteristic And Reliability Of Flexible Organic Thin-film Transistor

With the development of flexible electronic technology,flexible organic thin-film transistor as a basic electronic components has attracted extensive attention,but the mechanical stability and electrical performance of flexible organic thin-film transistor is still need to be improved for high-performance flexible organic thin-film transistor.To improve the mechanical stability and electrical performance of flexible organic thin-film transistor,in this work,the interface between gate insulator and semiconductor layer was investigated to explore the influence of interface adhesion energy on the flexible devices.Moreover,a novel method of the gate insulator modified with liquid small monomers to form double-network structure to obtain high performance flexible organic thin-film transistor was introduced.This work mainly includes several aspects as follows:1.To explore the effect of adhesion energy on the performance of flexible organic thin-film transistor,different gate insulators and surface modification methods were used to obtain different interface adhesion state.In this work,poly(perfluoroalkenyl vinyl ether)(CYTOP),polyvinyl alcohol(PVA),and poly(4-vinylphenol)was chose as gate insulator,and the gate insulator of cross-linked PVP film modified with UV-ozone and OTS to obtain different interface adhesion energy.As a decrease of interface adhesion energy,the interface trap density of the device was reduced,and the mobility of the device was increased.2.The effect of interface energy on the mechanical stability of the flexible organic thin-film transistor was investigated.The electrical performance of the device under different bending radius and bending cycles was measured.With an increase of bending deformation,the performance of flexible devices reduced,but performance of the device with lower adhesion energy was relatively litter influenced.The mobility of the device with highest adhesion energy reduced by79%after 300 bending cycles at a bending radius of 10mm,and the interface trap density increased from 1.38×1012cm-2eV-1 to 4.84×1012cm-2eV-1.However,the mobility of the device with lowest interface adhesion energy only reduced by 56%,and the interface trap density increased from 6.13×1011 cm-2eV-1 to 1.52×10-2cm-2eV-1?3.The gate insulator modified with monomer to form double-network structure could reduce the interface adhesion energy and tune the mechanical compatibility of the gate insulator and semiconductor layer,and prompt the formation of high performance flexible organic thin-film transistor.With an increase of bending cycles,the strain between gate insulator and semiconductor layer is unmatched,resulting in the accumulation of residual stress,which would directly affect the performance of the device.And the gate insulator with double-network increased the Young's modulus of the membrane,resulting in more matched with semiconductor layer to reduce the residual stress.Meanwhile,lower adhesion energy disturbed the formation of small islands on the interface,reduced the stress points on the interface,and decreased the inner stress during bending deformation.The device without modified with double-network structure did not exhibit transistor behavior after500 bending cycles,while the device modified with double-network retained the performance of transistor even after 500 bending cycles.