Design,Synthesis,Assembly And Optoelectronic Application Of Organic Semiconductor Materials

Organic semiconductor materials display tunable physicochemical properties,which ensures that they can be optimized to meet the requirements through appropriate chemical modification.As we all know,the performance of organic field effect transistors(OFETs),to a large extent,depends on the material structure and molecular stacking mode in the active layer.Therefore,organic donor-acceptor complexes are synthesized through supramolecular self-assembly to provide new insights into the relationship between structure and performance.Additionally,novel research approach based on molecular stacking adjusting is applied by tuning the organic semiconductor polymorphism of OFETs.This thesis has carried out a number of works on the design,synthesis and assembly strategies of organic semiconductor materials.The specific research work has the following three aspects:1:Three carbazole derivatives,1,4-di(9H-carbazol-9-yl)benzene(DCB),1,3,5-tri(9H-carbazol-9-yl)benzene(TCB)and 3,3',5,5'-tetra(9H-carbazol-9-yl)-1,1'-biphenyl(TCBP),which contain a tunable bridging linker and carbazole units,can be utilized to capture fullerenes.Fullerenes could interact with the planar carbazole subunits to form 2-dimensional hexagonal/quadrilateral cocrystals with alternating stacking patterns of 1:1 or 1:2 stoichiometry.Among three complexes,TCBP presented better capturing effects on fullerenes via the suitable cavity construct.At the meanwhile,good electron-transporting performances and significant photovoltaic effects were realized when continuous C₆₀-C₆₀ interaction channel existed.The experiment results indicate that the introduction of such carbazolic system into fullerene acceptor would provide to new insights into novel fullerene donor-acceptor architectures for versatile applications.2:By using a simple solution method which involves changing the concentration of the perylene imide derivative(4FPEPTC)solution,we successfully synthesized polymorphic 4FPEPTC crystals:one-dimensional needle-shape(?phase)and quasi-two-dimensional ribbon-like(?phase)crystals.The difference in the molecular packing modes of the two crystal phases leads to significantly different optoelectronic properties.Among them,the n-channel microcrystal devices prepared based on the two crystal phases demonstrated excellent electron transport performance.All the same,the?phase exhibited higher electron mobility than the?phase.In addition,the?phase and?phase microcrystalline devices showed to have significantly different light responsivity.It was found that the different molecular packings between the polymorphs caused significant changes in the optical and electrical properties of the material.This can help us to deeply understand the relationship between molecular packing and performance.3:Three novel perylene diimide derivatives(PDI-a S3,PDI-b S3 and PDI-c S3)were designed and facilely synthesized.Three novel perylene diimides featuring[1,2]dithiine and sulfur annulation onto the PDIs core and different branched alkyl chains.The organic thin film transistor(OTFT)devices based on the PDI-c S3 showed the maximum electron mobilities of up to 0.008 cm² V^-1 s^-1under the ambient atmosphere.Meanwhile,it revealed that the same molecular backbone had different effects on the crystallinity and grain size of the film due to the difference alkyl side chain length.