Fabraction And Characterization Of Organic Single Crystal Field-effect Transistors Based On Two-dimensional Curved Semiconductors

The organic field effect transistors(OFETs)has obtained unprecedented development since it was proposed.Compared with inorganic semiconductor materials,it has the advantages of wide material sources,simple preparation process,low fabrication costs,and flexibility.The organic field effect transistors as the basic component of modern electronic equipment has also received extensive attention from researchers.Organic semiconducting single crystals are more conducive to us to reveal the intrinsic properties of organic semiconductors and the relationship between different molecular structures and their performance are perfect for fundamental because they have long-range periodic order,and are free of grain boundaries as well as minimal traps and defects.Compared with planar conjugated compounds,the solubility and stability of two-dimensional curved conjugated compounds are significantly improved.Such compounds are easy to form some unique supramolecular structures,which have potential application value in organic optoelectronic devices.In this dissertation,a series of characterization methods are used to characterize the two-dimensional curved polycyclic aromatic hydrocarbon compounds,and make full use of its curved structure to prepare organic cocrystal to explore its carrier transport performance.1.We designed and synthesized a set of two-dimensional curved polycyclic aromatic hydrocarbon compound,which is TIPS-DBP and TIPS-DNP.We also explored the effect of the curved structure on molecular packing and carrier transport.Studies have shown that the curved structure can alleviate the unfavorable electrostatic interactions between adjacent molecules through a certain rotation when the molecules are stacked.So the molecules form a one-dimensional(1-D)π-stacking motif,which would improve the device performance.The crystal of TIPS-DBP shows a hole mobility up to 0.17 cm2 V-1 s-1,while the crystal of TIPS-DNP shows a hole mobility up to 0.74 cm2 V-1 s-1.2.We designed and synthesized is a new bowl-shaped compound which contains the subunit of C70,and explored the effect of buckybowl skeleton structures on molecular packing and carrier transport.The TES-ethynyl group helps with the arrangement of the buckybowls with strong concave-in-convex interactions.The distance of carbon atoms between adjacent molecules is 3.26-3.37 ?,which could favor charge-carrier transport.The bowl-shaped compound shows exclusive p-type ransport behavior with a maximum mobility up to 0.31 cm2 V-1 S-1,which the mobility of this compound is one of the highest values reported for buckybowls.While the 2,4,6-triisopropylphenyl substituent make the compound present a slipped dimer structures,so that it can not favor charge-carrier transport.3.We studied the cocrystal and carrier transport behavior of the bowl-shaped compound with C70.The 1H NMR test confirmed that the bowl-shaped compound and C70 can recognize each other and have a certain force in the solution;X-ray diffraction shows that the C70 is embraced by two bowl-shaped compounds,which forms a plate cocrystal.The cocrystals show ambipolar characteristics with maximum electron and hole mobilities of 0.4 and 0.07 cm2 V-1 s-1,respectively,along the(011)direction.