Application Of New Donor Receptor π-Conjugated Materials In Organic Field Effect Transistors

Organic semiconductor materials with high carrier mobility are one of the most important directions in the research of optoelectronic materials.Due to their good solution processability,large device area that can be prepared and simple refinement chemical modification,organic semiconductor materials are the most promising alternative to traditional inorganic semiconductor materials such as silicon-based and gallium arsenide based.Among organic semiconductor materials,organic field effect transistors are the most important components,which can be widely used in many fields such as flexible display,sensors,radio frequency identification and flexible electronic skin.However,the existing materials still face many defects that hinder their further applications,such as low carrier mobility and poor device stability.Therefore,it is necessary to further investigate the design and synthesis of new donor-acceptor materials and their performance improvement in organic field effect transistors.In this thesis,we obtained a series of donor-acceptor structure molecules for application in organic field-effect transistors through the fine design and synthesis of the structures of conjugated molecules.The organic field-effect transistor devices prepared by using such molecules as semiconductor layers have all obtained excellent performance,providing practical solutions as well as feasible theoretical bases for the design and preparation of future organic semiconductor molecules.In the second chapter,we designed and synthesized a novel donor-acceptor alternatively bound conjugated polymer PQ1,which was obtained by copolymerization of the electron-deficient unit quinoxaline and the electron-rich unit indandihydrodithiophene（IDT）via palladium-catalyzed Stille coupling.The obtained polymer PQ1 exhibited significant intramolecular charge transfer effects and obtained good solid film aggregation properties.Finally,the organic field-effect transistors prepared with PQ1 as the organic semiconductor layer obtained a carrier mobility of0.12 cm² V^-1 s^-1.In Chapter 3 of the main text,we introduced the concept of hydrogen bonding to enhance theπ-πstacking ability of the DPP-carbazole copolymer backbone.It was found that after undergoing the annealing process,the conjugated polymers achieved a type of cross-linked structure through the intermolecular hydrogen bonding force provided by thymine,which greatly facilitated the self-assembly ability of the backbone.Through this enhanced intermolecular interaction,the polymer P2containing the thymine moiety obtained a 5 times higher carrier mobility than before annealing.However,as a comparison,the polymer without the introduction of thymine units did not exhibit significantly enhanced intermolecularπ-πstacking even after annealing.