Design,Synthesis And Application Of Organic Conjugated Molecules Of Thiophene Naphthalimides

In recent years,organic semiconductor has attracted wide attention because of its advantages of large area preparation,printing preparation and flexible devices.Among them,the p type material with hole transmission develops rapidly,while the n type material with electron transmission develops slowly because it is unstable in the air and there are few available materials.Naphthalimide has the advantages of planar rigid structure,multiple modification sites,high electron affinity and strong stability.Therefore,n-type semiconductor materials based on naphthalimide have attracted much attention.Due to the difficulties in synthesis,there are not many studies on the direct binding of donor receptors based on thiophene and naphthalimide.The work of this paper is mainly focused on thiophene and naphthalimide molecules to develop,design and synthesis of a series of molecules,and their photoelectric properties were tested,mainly divided into the following three aspects:First,A novel asymmetric n-type semiconductor material is designed and synthesized.Thiophene condensed on the same side of the molecular naphthene and[2,3-b]thiophene and[3,2-b]thiophene diimide(NTTI)were obtained by selecting mercaptan,nucleophilic substitution of one-step coupling,n-bromo succinimide on bromine,and then through the selection of different catalysts,molecular c-h activation ring closed.The molecule exhibits a strong electron-polarized structure with a dipole moment of 2.09 D.NTTI compared to the symmetric naphthalene union[2,3-b:6,7-b’].-dithiophenediimide(NDTI)has changed in optical,electrochemical and electron transport properties.Data of single crystal devices based on C8-NTTI showed that the highest electron mobility reached 1.47 cm2 V-1 s-1,an order of magnitude higher than that of NDTI,with a switching ratio of 107.Second,through the selection of different positions of mercaptan,using a similar synthetic route,three NTTI isomers were obtained,and a series of their properties were described in detail.The thin film transistor test showed that S atoms in the upper and lower sides of the electron mobility of molecular NTTI-1 up to 0.47 cm2 V-1 s-1,S atoms on opposite side NTTI-2 molecules of crystal grain size larger,film grain boundary is bigger,electron mobility reduced to 0.018 cm2 V-1 s-1,and S atoms in the ipsilateral NTTI-3 weak electronic transmission performance,may be a molecular crystalline is too strong,too many defects,unfavorable and carrier transmission,electron mobility for only 1.4 × 10-5 cm2 V-1 s-1,indicating the position of the S atom,It has great influence on the electronic transmission performance and further realizes the regulation of thiophene position.Last,Bilaterally symmetrical dithiophene naphthalimide molecules were designed and synthesized,and their photoelectric properties were characterized.Through the reaction of dibromonaphthanimide with mercaptan,the target product was obtained by adding bromine to the ring,the number of thiophene was increased and the conjugation degree was increased.The single crystal of the compound was obtained by solution diffusion method.Compared with the unilateral asymmetric NTTI molecule,the conjugation degree increased and the absorption redshifted to 750 nm.Both oxidation and reduction peaks were observed in electrochemical test.Tests on organic thin film transistors showed that electron mobility reached a maximum of 0.12 cm2V-1 s-1 with a switching ratio of 107.