Preparation Of Two-Dimensional Schiff Base Polymer Films On Air-Water Interface And Its Application In Memristor

In the coming artificial intelligence era,the data processing unit is thought to be inefficient to meet the needs of increasing complexity of computation in the coming Big Data Era which brings huge power consumption because of the limitation of Moore's law.Memristor,with a typical three-layer sandwich structure including two electrodes and a storage layer in between,represents a leading candidate for next generation nonvolatile data storage device because it is easy to integrate with high density and good performance in data maintenance.In this dissertation,we developed a strategy to growth large-area two-dimensional covalent polymer films with controllable thickness at the gas-liquid interface by Schiff base reaction and explored the application of these materials in memristor.The results show that the memristor based on Schiff base two-dimensional polymer exhibits stable resistance conversion performance.In addition,through reasonable molecular design,hydroxyl groups are introduced into the two-dimensional polymer materials,and significantly enhances the stability and data maintenance of the device.The main results and achievements are as follows:1.According to the characteristics of the monomers,we developed two synthesis methods,“one-phase method”and“two-phase method”,to synthesize 2DP films with large area,high uniformity and adjustable thickness at the air-water interface by Schiff base reaction.The pore size,pore environment and functionality of the 2DP materials can be rationally designed by adjusting the chemical structure of the monomers.The universality of the“one-phase method”has been proved by preparation of two-dimensional polymer films with different pore size and funcationality at the gas-liquid interface.The method provides a good solution for designing and preparing two-dimensional covalent organic polymer films with large size,high uniformity and controllable thickness.2.Using 2DP_BTA+PDA film as the functional layer,we fabricated the Ag/2DP_BTA+PDA/ITO memristor with stable resistance switching performance.The synthesized freestanding 2DP films are porous,insulating,and most importantly,covalently linked,which is ideally tailored for non-volatile memristors based on conductive filament mechanism.The devices exhibit excellent switching performance with high reliability and reproducibility,and the ON/OFF ratios are in the range of10² to 10⁵,depending on the thickness of the film.The intrinsic flexibility of covalent organic polymer enables fabrication of flexible memory device on a polyimide film,and exhibited reliable memory performance as that on the rigid substrate.Moreover,the 2DP-based memory device shows outstanding thermal stability and organic solvent resistance,which are desirable properties for applications in wearable devices.3.By introducing hydroxyl groups into the 2DP films,we have significantly improved the stability and data maintenance properties of the 2DP memerisors.Electrical tests show that the 2DP_TAPB+DHC based memristor exhibits more stable resistance conversion performance than Ag/2DP_BTA+PDA/ITO.XPS experiment proves that the hydroxyl and imine groups in the material can coordinate with silver elements,which stabilizes the Ag conducting filaments and resulting in a more stable data storage capacity.Molecular simulations further validated this result.This results provide a guidance for improving the performance of 2DP based memery devices.