Photoelectric Performance Resesrch On Of Organic Semiconductor Devices Based Imide-based Small Molecules

In recent years,electronic devices based on organic materials have developed vigorously,organic semiconductor materials emerge in an endless stream,compared with inorganic semiconductor materials,organic semiconductor materials have the advantages of low cost,wide range of material sources,and large-scale preparation of flexible devices,which have received widespread attention.For organic semiconductor devices,the spatial structure and stacking mode of semiconductor layer molecules will affect the device performance,and the three-dimensional rigid molecules are conducive to the multi-directional transport of carriers.Curved molecules are conducive to improving the solubility of materials and facilitating the preparation of devices.Planar molecules favor intermolecularπ-πaccumulation and thus higher carrier mobility.The imide group has strong electron-absorbing characteristics and more active sites,which is conducive to structural regulation and functionalization,and is a widely used n-type semiconductor material.In this paper,the photoelectric properties of organic semiconductor devices were studied by a series of tests and characterization methods on three-dimensional rigid molecules,curved molecules and planar molecules of imides.1.Triperyleno[3.3.3]propellane triimide TNP-6CN and TNP-BF thin films and single crystal transistors were prepared,and the influence of groups with different electron-induced effects on the photoelectric performance of the device was explored.The introduction of cyanogen group deepens the LUMO energy level of the molecule to facilitate the transport of electrons,so that it exhibits n-type transport characteristics,and the introduction of benzofuran expands the conjugation system,which makes the HOMO energy level shallower and reduces the band gap of the molecule,making it exhibit p-type transport characteristics.UV-VIS absorption spectroscopy showed that TNP-6CN had stronger intermolecularπ-πforce,so it had higher device performance,electron mobility of 1.0×10^-3 cm²V^-1s^-1,photoresponsivity of 38 m A W^-1,and light-to-dark current ratio of 5.0×10⁴.The transistor mobility of TNP-6CN micro-nanocrystalline reaches 3.0×10^-3 cm²V^-1s^-1,and the carrier anisotropic transport test results show that the single crystal device has the ability of multi-directional charge transport.2.Thin-film transistors of perylmonoimide surface molecules 5HC_5,5and 5HC_8,12were prepared,and the influence of alkyl chains on charge transport performance was explored.Due to the weak intermolecularπ-πinteraction,the thin film device based on the short alkyl chain molecule5HC_5,5does not have a stable conductive channel,while the film rms roughness（RMS）of the film with the long alkyl chain molecule 5HC_8,12 is0.6 nm,and the surface is more uniform and continuous,which can effectively transport carriers,and its thin film field effect transistors exhibit bipolar transport,electron mobility of 7.1×10^-5 cm²V^-1s^-1,and hole mobility of 1.3×10^-4cm²V^-1s^-1.3.Single-crystal transistors of thieno-naphthimide molecules were prepared,and the effect of TIPS substituents on the charge transport performance of planar molecules was explored.The results show that the introduction of TIPS group in planar molecules will produce steric hindrance,which is not conducive to carrier transport,and the electron mobility of compounds without TIPS group is 1.7 cm²V^-1s^-1,and the planar heterojunction is constructed by physical transfer method,and the photoelectric performance of the diode based on planar heterojunction is tested,and the light-to-dark current ratio is 20.