Synthesis And Study Of The Applications In Organic Thin Film Transistors Of Naphthalimide Derivatives

The organic thin film transistor（OTFT）,which was first reported in 1986,shows great application potential in the field of flexible electronic products and is an important supplement to the traditional inorganic thin film transistor.OTFTs have some significant advantages over inorganic thin film transistors,such as the potential for flexibility in wearable portability,simple manufacturing,and a wide variety of organic semiconductor materials.Organic semiconductor materials are the leading factors that determine the performance of OFETs.In our experiment,three naphthalimide derivatives（NDIs）were synthesized and isolated,and used as n-type organic semiconductor materials in OTFTs.The specific contents of this paper are as follows:First,several typical application fields of OTFTs are introduced:sensor,memory,photodetector and flexible display.Second,the basic concepts of electron,hole,Fermi level and work function are introduced.Several common technologies for the preparation of OTFTs devices are briefly described.The device structure,working principle,working mode and key performance parameters of OTFTs are introduced in detail.Third,three naphthalimide derivatives were obtained by one-step reaction and purification.Thermogravimetric analysis show that they have good thermal stability,and CV cyclic voltamperes test confirm that their LUMO levels are all less than-4.0 e V.A batch of OTFTs devices are prepared using them as organic semiconductor materials by vacuum evaporation method respectively,and the semiconductor characteristics of the devices are tested,and the highest electron mobility obtained is 2.2×10^-1cm²V^-1s^-1.In the process of device preparation,the performance differences of the devices with gold and silver as source drain electrodes are simply compared,and the results show that the device based on gold electrodes has better performance.The effect of octadecyl phosphoric acid（ODPA）on the surface of Si O₂ insulation layer are studied and It is found that ODPA can significantly improve the film forming quality of organic semiconductor films and effectively improve the device performance.A variety of4,4’,4"-3（N-3-methylphenyl-N-phenylamino）triphenylamine（m-MTDATA）buffer layer materials with different thickness of evaporation are tried,and the principle of m-MTDATA reducing electron injection barrier and promoting charge transfer is analyzed.By means of XRD and AFM tests,the relationship between microstructure of organic semiconductor thin films and device performance is investigated.It is concluded that the higher the crystallinity of organic semiconductor,the better the film quality and the better the device performance.