Fabraction And Characterization Of Organic Single Crystal Field-effect Transistors Based On Bowl-shaped Polycyclic Aromatic Hydrocarbons

Organic electronics has developed rapidly since it was put forward,among which the organic field effect transistors（OFETs）have become one of the research hotspots due to their advantages of simple manufacturing process,rich material types,low cost and large-scale production.Organic single crystal field effect transistor have the advantages of fewer defects and no grain boundary,so it is easier to obtain the intrinsic properties of materials.It can be used to study the relationship between organic semiconductor molecular structure and charge transport.Compared with planar polycyclic aromatic hydrocarbons（PAHs）,bowl PAHs exhibit unique photoelectric properties due to the curvedπ-πconjugated system and can form cocrystal with fullerenes.In this paper,the OFETs based on a variety of bowl-shaped PAHs were prepared,the relationship between molecular structure and charge transport was explored by a series of characterization methods,organic cocrystals were prepared by using their bowl-shaped structures,and cocrystal-based field-effect transistors were prepared to explore their carrier transport properties.1.Two scallop-like molecules were designed and synthesized to explore the effect of different substituents on charge transport.The single-crystal nanowires of the two were prepared by solution method,and the molecular stacking modes of the two single-crystal nanowires were determined by X-ray electron diffraction and selected electron diffraction.The tri（isopropyl）silicyne compound showed one-dimensional columnar packing,and the intermolecular packing was more compact,so it had better device performance.Based on the two field effect transistors,the tri（isopropyl）silicylene compound has obtained the 0.177 cm²V^-1s^-1hole mobility,and the tert-butyl compound has obtained the 0.1 cm²V^-1s^-1 hole mobility.2.Two kinds of bowl molecules were designed and synthesized to explore the effect of substituents on charge transport.Single crystal nanowires were prepared by solution method,and the molecular packing mode of pyridine substituent compound was determined by X-ray electron diffraction and selected electron diffraction.Due to the steric hindrance of the substituent,the pyridine substituent compound exhibited two-dimensionalπ-πpacking,but the pyridine substituent group participated in the intermolecular charge transport,thus improving the device performance.The field-effect transistors based on the two are prepared with the hole mobility of 0.1 cm²V^-1s^-1 for pyridine and 0.05 cm²V^-1s^-1 for tri（isopropyl）silicon-based compounds.3.Organic cocrystal was prepared by mixing pyridine-substituted compound with fullerene C₇₀ in solution.The molecular packing mode in rhombic cocrystal was determined by X-ray electron diffraction and selected electron diffraction.In cocrystal,each C₇₀ was arranged alternately with pyridine substituent compound,forming the-DADA-alternating packing mode.The compact packing structure between the receptor molecules provided an effective channel for electron transport,and cocrystal field-effect transistor was prepared.The electron mobility is 5×10^-5 cm²V^-1s^-1,which provides a reference for the design and selection of acceptor molecules in eutectic materials.