Synthesis And Electrical Memory Properties Of Polyimide Materials Containing Triphenylamine And Perylene Imide

In the context of today’s big data era,the shortcomings of traditional silicon-based electrical storage devices are becoming more and more obvious,such as large size and high cost,which urges scientific researchers to conduct more in-depth exploration of new electrical storage materials.Organic electrical storage materials have the characteristics of high unit storage density and low cost,and have the possibility to replace traditional silicon-based materials as new electrical storage device materials in the future,attracting the attention of researchers who focus on new electrical storage materials.Polymer materials are an important direction in the field of organic electrical storage materials.Polyimide materials are a representative polymer material with excellent mechanical properties,thermal properties and other properties.Therefore,polyimide electrical storage materials have aroused the research enthusiasm of researchers.Polyimide material is a general term for a kind of polymers with-CNC-skeleton.Because of its generally good chemical stability,solvent resistance,mechanical properties and easy synthesis,it has mature products in many fields,being known as"the most promising engineering plastics in the 21st century".The polyimide materials containing both electron-donor and electron-acceptor groups in the molecular structure are easy to form charge transfer complexes under the applied voltage,so that the electrical storage device based this material exhibits an electrical bistable state.In this paper,three polyimide materials containing triphenylamine and perylene imide groups were synthesized,used as functional layers to prepare electrical storage devices,and the electrical storage properties of the devices were tested.The electrical storage mechanisms of the devices have been discussed.The main research results are as follows:1.Using 4,4’-diaminotriphenylamine(DATPA)and 3,4,9,10-perylenetetracarboxylic dianhydride(PTCDA)as monomers and m-cresol as solvent,the polymer DATPA-PTCDA was synthesized.The molecular structure and optoelectronic properties of the polymers were characterized by nuclear magnetic resonance,Fourier transform infrared spectroscopy,elemental analysis,electrochemical cyclic voltammetry,and UV-vis absorption spectroscopy.An electrical storage device(ITO/DATPA-PTCDA/Al)was prepared with polymer DATPA-PTCDA as the functional layer,and its electrical storage performance was studied.The experimental results show that the device has unipolar write-once-read-many(WORM)non-volatile memory performance,with a transition ratio of 10~5,a threshold voltage of+3.4 V,and good device stability.After optimizing the structural unit of the polymer DATPA-PTCDA,quantum chemical theoretical calculation and mathematical curve fitting analysis were carried out.The calculation and analysis results show that the HOMO and LUMO energy levels of the material are distributed on the triphenylamine and perylene imide units,respectively,and the charge transfer complex formed under the action of an electric field is relatively stable.Thus,shows a WORM-type electrical storage behavior.The conduction model of the device conforms to the Ohmic Current Model and the Space Confinement Current Model(SCLC).2.Using tris(4-aminophenyl)amine(TAPA)and PTCDA as monomers and m-cresol as solvent,the hyperbranched polymer TAPA-PTCDA was synthesized.The molecular structure and optoelectronic properties of the polymer were characterized by nuclear magnetic resonance,Fourier transform infrared spectroscopy,elemental analysis,electrochemical cyclic voltammetry,and UV-vis absorption spectroscopy.An electrical storage device(ITO/TAPA-PTCDA/Al)was prepared with the polymer TAPA-PTCDA as the functional layer,and its electrical storage performance was studied.The experimental results show that the device has bipolar erasable(FLASH)non-volatile memory performance,the transition ratio is 10~3,the write threshold voltage is+2.7 V,and the device stability is good.After optimizing the structural unit of the polymer TAPA-PTCDA,quantum chemical theoretical calculation and mathematical curve fitting analysis were carried out.The results of computational analysis show that the HOMO and LUMO energy levels of the material are distributed on the triphenylamine and perylene imide units,respectively,and the hyperbranched structure affects the stability of the charge transfer complex formed under the action of an electric field.The formed charge transfer complex is easily dissociated,thereby the device exhibits an erasable FLASH-type electrical storage behavior.The conduction model of the device conforms to the Ohmic Current Model and the Space Confinement Current Model(SCLC).3.Using tetraphenyl porphyrin with an amino group(STAPP)as the capping agent,the porphyrin-capped hyperbranched polymer TAPA-PTCDA-STAPP was synthesized.The molecular structure and optoelectronic properties of the polymer were characterized by nuclear magnetic resonance,Fourier transform infrared spectroscopy,elemental analysis,electrochemical cyclic voltammetry,and UV-vis absorption spectroscopy.An electrical storage device(ITO/TAPA-PTCDA-STAPP/Al)was prepared with the polymer TAPA-PTCDA-STAPP as the functional layer,and its electrical storage performance was studied.The experimental results show that the device has bipolar erasable(FLASH)non-volatile memory performance,the transition ratio is 10~4,the write threshold voltage is+1.97 V,and the device stability is good.After optimizing the structural unit of the polymer TAPA-PTCDA-STAPP,quantum chemical theoretical calculation and mathematical curve fitting analysis were carried out.The calculation and analysis results show that the HOMO and LUMO energy levels of the material are distributed on the triphenylamine and perylene imide units,respectively,and the conduction model of the device conforms to the ohmic current model and the space confinement current model(SCLC).Compared with the polymer materials in Chapter 3,the introduction of end-capped porphyrin groups improves the electrical storage performance of the device,reduces the transition voltage,and leads to smaller energy consumption and lower usage requirements in practical applications.