Synthesis And Properties Of Polythiophene Derivatives Containing Fluorobenzene Structures By Direct C-H/C-H Cross Coupling Polymerization

Polythiophene and its derivatives have been widely applied in the fields of organic solar cells,organic field-effect transistors,organic light-emitting diodes,chemical and biological sensors and so on.Due to the good planarity,aromaticity and strong electron-withdrawing nature of fluorobenzenes,it can effectively regulate the energy level distribution of polythiophene derivatives and optimize the efficiency of various devices.So the polythiophene derivatives with fluorobenzene structures have attracted extensive attention.At present,the main synthesis methods of polythiophene derivatives with fluorobenzene structures include Stille and Suzuki coupling polycondensation methods.These methods usually require pretreatment of monomers to prepare corresponding organometallic compounds or halogenated compounds.The conditions of synthesis methods are severe and the polymers need to be capped.In this paper,a series of polythiophene derivatives with fluorobenzene structures were prepared by direct C-H/C-H cross coupling polycondensation.And the optical property,electrochemical property,crystallinity and thermal stability of the copolymers were systematically studied.The main research contents are as follows:1.Synthesis and properties of polythiophene derivatives with asymmetric fluoroquinoxaline structures.A series of polythiophene derivatives(P1-P5)containing asymmetric fluoroquinoxaline structures were prepared by direct C-H/C-H cross coupling polycondensation.The effect of the monomers structures of thiophene derivatives on the copolymerization was investigated.The results showed that the yields and number average molecular weights of copolymers decreased,while the conjugation degree of copolymers increased,with the increase of structural rigidity of thiophene derivatives monomers.And the introduction of long alkyl chain into the thiophene derivative monomers could improve the yields and the number average molecular weights of the copolymers.2.Synthesis and properties of polythiophene derivatives with symmetrical fluoroquinoxaline structures.A series of polythiophene derivatives(P6-P11)with symmetrical fluoroquinoxaline structures were prepared by direct C-H/C-H cross coupling polycondensation.The photoelectric properties,crystallinity and thermal stability of the copolymers were investigated in detail.The results showed that theintroduction of fluoroquinoxaline units into the polythiophene ester structure could reduce the highest occupied molecular orbital(HOMO)energy level and increase the thermal stability of polythiophene ester.3.Synthesis and properties of polythiophene ester derivatives with fluorobenzene structures.A series of polythiophene ester derivatives(P12-P17)with fluorobenzene structures were prepared by direct C-H/C-H cross coupling polycondensation.The photoelectric properties,crystallinity and thermal stability of the copolymers were investigated in detail.The results showed that the introduction of fluorobenzene structures could reduce the HOMO and lowest altitude molecular orbital(LUMO)energy level and increase the thermal stability of polythiophene ester.