Research On Preparation And Performance Of Memristor Based On Organic Polymer

With the development of digital economy,5G,Internet of Things,cloud computing,and artificial intelligence,human society has entered the era of big data,which puts forward higher requirements for data storage.Many new memory devices also quickly attracted the attention of many researchers,including ferroelectric random access memory,magnetic random access memory,phase change random access memory,and memristor.Among them,memristors have great potential in realizing high storage capacity,fast data transmission,short access time,low power consumption and synaptic bionics due to their considerable miniaturization prospects,which can meet the needs of the era of big data and artificial intelligence.A key requirement for smart technology,it is considered to be one of the devices most likely to replace current memory in the future.Most of the current reports on memristor materials focus on inorganic materials.However,compared with traditional inorganic materials,organic materials have the characteristics of good flexibility,low cost,light weight,easy processing,and large-area film formation,which are more suitable for the preparation requirements of modern flexible electronic devices,which makes organic materials the future one of the important candidates for memristor dielectric layer materials.Therefore,in this paper,a series of novel organic polymer memristors with excellent properties were designed and fabricated based on organic polymers as substrates or resistive-switching dielectric layer materials.With the help of various characterization methods,their morphology,composition and structure were analyzed,and electrical tests were carried out on the devices,and the following conclusions were obtained:1.Organic polymer memristor with Ag/FC/Ag/Polyimine structure was prepared by spin coating and magnetron sputtering with organic polymer polyimine as flexible substrate and biomacromolecule fish colloid(FC)as resistive variable dielectric layer material.The entire device has a memory operation that can write and read data repeatedly.It is worth noting that the polyimide films linked by dynamic covalent chemical bonds endow the devices with flexible,recyclable,repairable,and rapidly decomposable properties.As a flexible device,the resistive characteristics remain stable after repeated bending for 300 times.The flexible device also exhibits a gradual increase in current with voltage stimulation,which is expected to be applied to simulate the sensitization and habituation of biological synapses.Finally,a physical model of the electrochemical metallization mechanism(ECM)forming conductive filaments is proposed to explain the resistive switching behavior of the device.2.Using 3,3-dithiophene(33DTh)and thiophene(Th)as monomers,33DTh homopolymerized P33DTh and 33DTh and Th copolymerized PTh-33DTh were prepared on flexible substrate ITO/PET by electrochemical polymerization.A flexible organic polymer memristor with Ag/polythiophene/ITO/PET structure was prepared by magnetron sputtering.Among them,the Ag/P33DTh/ITO/PET memory device exhibits the characteristics of unipolar double switching,with a switching ratio of 10~4.Selecting different compliance current tests,each resistance state can be stably maintained for 10~4 s under a constant voltage of 1 V,and it is expected to achieve multilevel memory,which is in line with our expected design.The analysis of the test data revealed that the resistance switching mechanism of P33DTh is composed of the conductive filaments formed by the trapping of charge traps and the ECM,in which the conductive filaments are dominant.In addition,the test results show that,compared with PTh-33DTh,the P33DTh film is more regular and ordered,and has a higher crystallinity,so it is more conducive to the migration of charges in the device,thus showing more excellent memristive performance.3.Using 4,4’,4’’,4’’’-(pyrene-1,3,6,8-tetrayl)tetraaniline(Py TTA)and[2,2’]-bisthiophene-5,5’-dicarbaldehyde(BTDA)as precursors,we designed and synthesized a covalent organic framework(COFs)material containing electron donor/acceptor(D-A)system,which is called Py BT-COF.Using Py TTA and terephthalaldehyde(PA)as precursors,a Py PA-COF material without D-A system was synthesized as a comparison.The two COFs materials were fabricated into Ag/COFs/ITO memory devices by magnetron sputtering.Different from Py PA-COF,Py BT-COF introduces a strong electron-donating unit called thiophene group in the design and synthesis,which can promote the electron carrier transport between the COFs frameworks,thereby realizing the change of its resistance switch between two states.The superior thermal stability and solvent stability of COFs materials were proved by thermogravimetric analyzer and solvent immersion method,which makes memristors based on COFs materials expected to play an important role in the changing and harsh working environment in the future.