Synthesis And Performance Study Of Random Conjugated Polymers And Chiral Small Molecules Based On Naphthalene Diimide

Naphthalimide is a type of classic electron acceptor unit,which possesses low LUMO energy level,good thermostability and chemical modification.Therefore,it's used to construct n-type organic semiconducting materials.As a synthetic strategy,random copolymerization is devoted to adjusting the electronic energy level,absorption spectrum and crystallinity,which could develop a variety of organic semiconducting materials to meet the needs of applications.The performance of the materials is not only related to the characteristic of molecule,but affected by the aggregation structure,respectively.In addition,the chirality can induce different aggregated state.In this paper,a series of organic optoelectronic functional materials based on naphthalimide were synthesized,then the corresponding physical and chemical properties were studied.What's more,we also prepared the organic field-effect transistors with bottom-gate topcontact structure and tested their performance.The main contents of this thesis are as follow:1.A series of random conjugated polymers(P1-P5)were synthesized by 1,2,5,6-NDI,1,4,5,8-NDI and dithiophene.Meanwhile,the physicochemical properties were characterized by TGA,DSC,UV-vis and cyclic voltammetry.All polymers had good thermal stability(Td > 450 ?),and the ultraviolet absorption spectrum showed the different ratio of two acceptor units could adjust the absorption range of the materials,respectively.Furthermore,the CV curves indicated that random copolymerization did achieve to adjust the LUMO energy level.In addition,the OFET device based on P3 showed quite balanced bipolarity(?e=1.29 × 10-3 cm²V^-1s^-1,?h= 4.84 × 10-3 cm²V^-1s^-1),while P1 and P5 both displayed uncoordinate bipolarity(P1 was dominated by hole carrier with 0.132 cm²V^-1s^-1,P5 was dominated by electron carrier with 0.03 cm²V^-1s^-1).It proved the random copolymerization realized the regulation of the type of carrier transport.The result will provide valuable insights for the development of naphthalimide polymer.2.Chirality could induce different aggregated structures then affect the properties of materials.Therefore,we designed and synthesized the optically pure compounds(IV-5-R,IV-5-S)and mesomer(IV-5-R,S),moreover obtained racemic mixture(IV-5-rac)by mixing IV-5-R and IV-5-S equimolarly.The physical and chemical properties were characterized by TGA,DSC,UV,circular dichroism and cyclic voltammetry.The UV absorptions in solution were consistent,while the absorptions in film were slightly different,indicating the unequal aggregate structures.Whar's more,the mesomer(IV-5-R,S)and racemate(IV-5-rac)showed better OFET performance than the optically pure compounds,with hole mobility of 0.074 cm2·V-1·s-1 and 0.075 cm2·V-1·s-1.The result will bring out a design thinking for developing naphthalimide-based organic functional molecules.