Research On Transistor Memory And Synaptic Properties Of Benzodithiophene Derivatives

With the continuous progress of information technology in the Internet of Things,the emerging technologies such as artificial intelligence and machine learning have greatly promoted the development of memory research.However,with the advent of the post-moore era,memory is facing the limitation of quantum limit.The development of silicon-based memory has reached the limit of physical size,which can not meet the needs of applications.Therefore,the development of a new generation of memory has become the focus of current research.Organic Field-Effect Transistor memory(OFET memory)is expected to become an alternative to traditional memory because of its high scalability,non-destructive programming and erasing,low power consumption,simple preparation process,and suitable for large-area flexible integration.Because of its simple molecular design and accurate electronic structure,small molecule memory materials are suitable for further studying the relationship between molecular structure and memory mechanism,and improving the performance of memory.Benzodithiophene derivatives have been widely studied in optoelectronic devices for their high mobility,controllable narrow band gap design,π-π conjugate stacking and strong self-assembly properties.This thesis focuses on the organic field-effect transistor memory performance and synaptic properties of novel benzodithiophene-based photosensitive memory materials to investigate the effect of molecular structure on memory charge trapping,the Optical,electrical and film morphologies of molecules were characterized systematically by combining the physical and chemical properties of the materials,which further expanded the applications of the materials in mass storage,light-regulated storage and artificial synapse.The main research contents and findings are as follows:1.Using Benzo [1,2-b: 4,5-b’] dithiophene(BDT)as the core,the functional modification of the active site 4,8 was carried out,the small molecular storage materials TPA-BDT and TIPS-BDT with central symmetry and triphenylamino and triisopropylsilyl ethynyl substituents were successfully prepared.The effects of TPA group and TIPS group introduction on the spectra,energy levels and charge transfer of the materials were investigated,and the storage parameters of the device were systematically investigated by introducing the above-mentioned materials into OFET memory,such as storage window,fast write,maintenance time,read and write cycle.The effects of TPA group and TIPS group on charge capture and storage capacity were revealed by comparing the regulation of different functional groups.The responsivity of these materials to different color light and different intensity light was investigated,and the responsivity of different functional groups to lightregulated storage was revealed,furthermore,the effect of the material structure on the charge transfer is analyzed and the device storage mechanism is clarified.2.The molecular structure of TIPS-BDT was further regulated and designed by the introduction of the procyanidin group and Triisopropyl silicon acetylene group,two benzodithiophene derivatives,CN-TIPS-BDT and TIPS-TIPS-BDT,were successfully designed and their optical,electrical and film morphologies were analyzed,the effects of Inductive effect on charge trapping and light-regulated storage were also studied.CN-TIPS-BDT and TIPS-TIPS-BDT show better electrochemical stability and morphology,and broaden the visible light absorption band.In order to further compare the performance of light-controlled storage,the differences of different materials in the application of devices,including the parameters of storage window,maintenance time and readwrite-erase cycle under different illumination and light intensity,were further compared,the design method of improving the performance of OFET memory with Inductive effect pair is verified.3.To simulate the function of artificial synapses,OFET synapses were designed with TIPSBDT and TIPS-TIPS-BDT.By changing the electrical parameters such as voltage amplitude,pulse number and pulse time,the plasticity of synapse enhancement and suppression is realized,which provides a feasible implementation strategy for the study of transistor synapse.