Design,Synthesis And Performance Research Of Novel Polycyclic Aromatic Imide Molecules

The design,synthesis and performance research of novel organic conjugated functional molecules are the basis for the development of high-performance organic semiconductor materials.Due to the large?-conjugated structure,photothermal stability,chemical stability,high carrier mobility,and excellent photoelectric performance,polycyclic aromatic imide molecules have attracted great attention from researchers.The research work of this thesis mainly selected naphthalimide and tripterene as the functional framework,and designed and constructed a series of polycyclic aromatic imide molecules,namely novel organic conjugated functional molecules.We have studied their photoelectric properties and preliminary explored the device performance in organic field effect transistors.The main research contents are as follows:Firstly,a number of benzothiophene compounds based on naphthalene diimides were synthesized simply and efficiently through cross-coupling reaction combined with carbon-hydrogen bond activation ring-closing reaction.The structure was clearly characterized by nuclear magnetism,mass spectrometry and X-ray single crystal diffraction.The analysis result demonstrated that the products contained both cis-isomer and trans-isomer,then we discussed the production mechanism of cis-isomer and trans-isomer.Then,we synthesized benzothiophene compounds based on naphthalene diimides which possess only single trans-configuration molecule,through naphthalic anhydride esterification ring-opening reaction and strong acid-induced ring-closing reaction,combined with cross-coupling reaction and carbon-hydrogen bond activation reaction.Electrochemical performance tests indicate that these compounds possess lower and similar LUMO energy level.The device performance indicate that the maximum OFET electron mobility of these naphthalimide-based benzothiophene compounds is as high as 0.0246cm²V^-1s^-1.These results indicate that the compounds are excellent n-type organic semiconductor materials.Secondly,Through cross-coupling reaction combined with carbon-hydrogen bond activation reaction,benzothiophene compounds containing trifluoromethyl and methoxy groups based on naphthalene diimides were synthesized simply and efficiently.The analysis result demonstrated that the products contained both cis-isomer and trans-isomer.Electrochemical test results indicate that the introduction of trifluoromethyl into the molecule can significantly reduce the LUMO energy level,while the introduction of methoxy groups can increase the LUMO energy level.The maximum electron mobility of the device based on the methoxy-containing compound is 0.006 cm²V^-1s^-1,and the maximum electron mobility of the device based on the trifluoromethyl compound is 0.26 cm²V^-1s^-1.It indicates that the introduction of the electron withdrawing group trifluoromethyl into the molecule can significantly improve the performance of the device.This provide an idea for improving the performance of molecules by designing molecules with different structures,and then regulating the energy levels of the front orbital of the molecules.Thirdly,we synthesized some benzofuran compounds based on naphthalimide,through cross-coupling reaction combined with carbon-hydrogen bond activation ring-closing reaction.The optical property test results indicate that these compounds have similar ultraviolet-visible absorption spectra and fluorescence spectra,indicating that different substituents have little effect on their optical properties.Electrochemical performance test indicate that these molecules have low LUMO energy level.The organic micro-nano crystal field effect transistor of this molecule shows very good device performance,and the electron mobility is as high as 0.820 cm² V^-1 s^-1.The above results indicate that this type of compound is excellent n-type organic semiconductor material.Lastly,it is the first report to synthesize two novel polycyclic aromatic imide molecules with three-dimensional symmetrical structures,namely triptycene fused naphthalene monoimide and triptycene fused perylene monoimide molecules.The electrochemical test results indicate that these molecules possess lower LUMO energy level.The UV-visible absorption spectroscopy test results indicate that the conjugated structure of perylene monoimide and triptycene produces a larger red shift(167nm),which is caused by its conjugation degree increased significantly.The electrochemical properties and UV-visible absorption of the two new conjugated molecules are compared with their monomers,respectively,which indicate that exist electronic coupling between the three subunits of the two new conjugated molecules.Such materials have potential application value in the study of singlet splitting and light-emitting devices.This novel molecular synthesis method has laid the foundation for the further synthesis of organic semiconductor materials with greater conjugation degree and higher performance.