Application Of Aromatic Diimides And Flavanthrone Derivatives In Organic Semiconductor Devices

Electronic plays an important role in the rapid development modern information society,which has driven the development and innovation of new technologies,new materials and new devices,and has spawned a large number of modern technologies and industries.As an important branch of modern electronics,organic electronics plays an increasingly important role in our lives.Compared with inorganic semiconductors,organic semiconductors have many advantages in the fabrication of storage,sensing,information display,photoelectric conversion devices.For example,organic materials are light,low in cost,easy to chemically modify,compatible with flexible substrates and can be prepared by large-scale solution processing.In recent years,the research of semiconductor devices has attracted more and more researchers’attention,including:organic solar cells（OSC）,organic field-effect transistors（OFET）and organic memories（organic Memory,OM）,etc.Nonvolatile organic field-effect transistor memory devices（OFET-NVM）,was expected to be used in a new generation of high-density storage devices for portable or flexible electronic devices.In this thesis,we have prepared a series of aromatic diimides as n-type doped materials and a series of soluble small molecule derivatives based on flavanthrone and pyranthrone as p-type doped materials for nonvolatile organic field effect transistor memory devices.We also synthesized flavanthrone derivatives substituted with a series of alkoxy chains and fabricated bottom-gate top-contact organic field effect transistors.This research provided guidance for the applications of organic semiconductor materials in organic field effect transistors and memories.The main contents of this thesis are listed below:1.Memory devices based on n-type dopant materials were prepared using a series of aromatic diimides as the n-type dopant material of the electret layer.The obtained memory devices exhibited a wide memory window and a high on/off ratio.We have compared the performance of three representative aromatic diimide skeletons as n-type doped materials by characterizing the film morphology,basic optoelectronic properties and Gaussian calculation.Among them,the momery device based on pyrene diimide exhibited superior performance,achieving a maximum memory window of 34.0 V,a trapped charge density of 1.98×10¹² cm^-2,and an on/off ratio more than 10⁴.This work indicated that the pyrene diimide structure may be a new platform for designing n-type dopants for high-performance nonvolatile OFET memory devices in the future.2.A series of soluble small molecule derivatives Fla-OC8,Fla-OEH and Fla-OBO based on flavanthrone were successfully synthesized.Three simple alkoxy chains of different sizes were introduced to flavanthrone through simple synthesis methods.The three molecules were characterized by theoretical calculation,electrochemical measurement,ultraviolet-visible absorption spectrum measurement and thermogravimetric analysis,which showed good solubility and strong light absorption.The organic field-effect transistor devices based on these three molecules were successfully prepared and tested.Among them,Fla-OC8 achieved the highest field effect mobility of 4.1955×10^-4 cm²V^-1s^-1.3.The application of flavanthrone and pyranthrone derivatives Fla-OEH,Fla-OBO,Fla-TIPS and Pyr-TIPS in the nonvolatile organic field effect transistor memory devices were fabricated and their storage performance were characterized.It has shown that the memory windows of thin films doped with small organic molecules are improved compared to polystyrene films as charge storage layers.Among them,Fla-TIPS has been the best storage performance,achieving a memory window of 22V.