Study On Organic Memristor With A Small Molecular Donor-acceptor Porphyrin

With the rapid development of microelectronics,the traditional storage technology still can not meet the increasing needs of science and technology development.Memristor,as one of the four basic components of the circuit,has the advantages of simple preparation,diverse performance,fast and stable storage of information,and less limiting dimension,so it is considered as the most promising next generation storage technology.Compared with the traditional inorganic memristor,the organic memristors are made up of a wide range of organic materials that are low cost,environmental-friendly,low energy consumption and ease of use.In this paper,a series of organic memristors were designed and fabricated based on solution-processed conjugated Zn-porphyrin small molecules.The preparation,performance and working mechanism of the devices were studied in depth.The functions of different layers in the devices were revealed.The main contents of this paper are shown as below:1.Preparation of high-performance organic memristors.The comprehensive electrical performance of the memristor with the structure of ITO/WO₃/Zn-porphyrin/Ag was studied.It is found that the thickness of organic layer has a great influence on the performance of memristor and the resistance of inorganic WO₃layer greatly influences the working stability of memristor when compared to the single devices with the structures of ITO/Zn-porphyrin/Ag and ITO/WO₃/Ag.Furthermore,it is found that the zinc metal atoms in porphyrin molecules are extremely important.Finally,we get the good high/low resistance ratio of 10³with the very low V_setof 0.38 V and low V_resetof-1.8 V.There is no obvious resistance vibration after more than 180 times of cycle test and the resistance can be held at the same value after tens of thousands of continuous reading measurement,indicating the reliability and stability of this energy-saving memristor are very good.The above experimental results show that it is very important to study the working mechanism of organic memristors based on donor-acceptor porphyrin materials.2.The working mechanism of ITO/WO₃/Zn-porphyrin/Ag memristor was investigated.We measured and analysized the internal elements distribution and valence state in different positions of high resistance and low resistance devices.The cause of resistance change is not based on the electrochemical metallization,but dominated by the valence change mechanism,according to the experimental results.We establish the corresponding band model and depict the working mechanism of each process,providing a clear and reliable experimental theory model for this type of memristor.