The Application Of Interface Modification In Flexible Devices

With their unique characteristic of flexibility,ductility and low-cost manufacturing process,flexible electronics have broad applications in information technology,medical treatment,energy and defense sectors.After decades of development,flexible electronics have emerged with a large number of commercial products under the joint efforts of academia and industry,such as organic light-emitting diodes(OLED),flexible electronic displays,radio frequency identification devices(RFID),thin-film solar cells,etc.With the rapid development,the application field of flexible electronics has been expanded,and more practical products will be fabricated,which will bring huge convenience to our life.Flexible electronics are becoming one of the researches focuses.The preparation of flexible electronics usually requires the preparation of functional materials on the surface of flexible substrates,so a large number of strategies about interface engineering is involved in the preparation process.Interface is the boundary between different materials and phases.The defects,stress and stability of interface would determine the electrical performance and durability of flexible devices.Therefore,exploring the mechanism of the interface influencing the performance of flexible electronics and thus,developing a reasonable interface engineering is of great significance to the construction and application of flexible electronics.Based on the above,this manuscript focuses on the interface of flexible electronics.First,we construct a reasonable interface structure and adjust the physical and chemical properties of the interface through effective and simple processes.Then,we have explored and optimized the interface modification process,and develop effective strategies to control the physical and chemical properties of the interface.Finally,the mechanism of the physical and chemical properties of the interface on the performance of flexible devices will be revealed to construct flexible electronics with high performance.Focusing on the key points mentioned above,this dissertation is mainly based on plasma or chemical modification to modify the interface with different physical and chemical properties of the,adjust the adhesion,morphology and surface energy of the material interface,and then construct flexible wearable devices and organic field-effect transistors(OFET),which mainly includes the following contents:(1)Inspired by the alternate arrangement structure of banded scales and elastic skin on the back of the armadillo,we combined characteristics of the plasma process with the physical and chemical properties of polydimethylsiloxane(PDMS)film.A PDMS substrate with a micro-folded crack structure constructed by an alternating hard silicon oxide layer(SiOx)and the elastic layer was prepared,and a high-performance stretchable electrode was fabricated with this substrate.The stretchable electrode has been successfully applied to the detection of muscle electrical signals and strain sensors.(2)With the strong permeability of the PDMS membrane,gaseous(3-mercaptopropyl)trimethoxysilane(MPTMS)can quickly permeate to the interface between PDMS and PEDOT:PSS membrane under vacuum,and covalently bond happens.Large-area PEDOT:PSS membrane is successfuly and efficiently transferred and patterned to the surface of PDMS membrane to form a composite bilayer membrane.Based on the bilayer membrane with different surface structures.A flexible pressure sensor and a heat-sensitive flexible actuator with high sensitivity and good stability are constructed respectively by adjusting the thickness of the bilayer membrane.(3)By changing the plasma process,the surface energy,surface groups,and charge distribution of the organic field-effect transistor dielectric layer are adjusted,and then the morphology of organic semiconductor deposition is changed.The influence of the physical and chemical properties of the interface on the device performance is revealed in detail,and the threshold voltage,stability and hysteresis of the device are effectively modulated.