Design And Synthesis Of Organic Optoelectronic Function Molecules Containing Sulfur And Selenium Elements

Incorporation of heteroatoms is an important strategy for the design of high property organic optoelectronic materials.Many compounds containing sulfer atoms have shown excellent properties,such as polythiophene,benzothiophene derivatives,fused thiophene compounds etc.Selenium atom which is in the same main group of sulfer has similar physical and chemical properties as sulfur atom,but has a larger radius,higher polarizbility,and can accommodate more charge injection.In addition,selenium-containing organic compounds tend to have tight molecular arrangement in the solid state due to Se-Se interactions between molecules,which facilitates the carrier transport.Besides,selenium has a heavy atom effect,which increases the spin-orbit coupling ability.This phenomenon promotes intersystem crossing(ISC),and is beneficial to the generation of triplets.The oxidation-reduction potential of selenophen is lower than that of thiophene,which can enhance the stability of the material.Therefore,replacing sulfur with selenium in many provide an effcient strategy for the development of high-performance organic optoelectronic materials.This thesis aims at design and synthesis of novel organic semiconductors by introducing S,Se and other heteroatoms into organic aromatic compounds.The optical and electronic properties of these new compounds were explored by theoretical calculations and experimental studies.The main contents of this thesis are listed below.1.A series of strong electron donating conjugated aromatic hydrocarbon containing thiophene and selenophene which were named BTT,CTT and BTS,have been designed and synthesized.Organic co-crystals of these new molecules(1:1)with organic acceptors(such as TCNB and TCNQ)were obtained by molecular self-assembly.Through theoretical calculations and spectroscopic studies,the charge transfer properties in the three new organic co-crystals were confirmed.The single crystal structure and optical properties indicated that the introduction of different types and positions of heteroatoms have affected the stacking and luminescence performance of the organic co-crystals.Due to the existence of two different packing methods between CTT and TCNB,micro/nano-crystals with three-dimensional shape have observed.Obvious optical waveguide phenomenon can be observed under fluorescence microscope.The introduction of heavy atom Se leaded to a decrease in the fluorescence intensity,lifetime and quantum yield of the co-crystals.A stronger charge transfer interaction between the co-crystals was generated,and the emission peak was red-shifted,which was beneficial to regulating the luminescence of the co-crystals.2.Assisted by theoretical calculations,a series of organic condensed ring molecules based naphthylene have been designed and synthesized.By predicting the single crystal structure,the calculated single-crystal hole mobility of the naphthodiselene derivative was greater than 10 cm~2/V·s,which was an order of magnitude greater than the hole mobility of the naphthodikethiophene-based analogs.Explored the preparation of single crystal devices,and tried to verify the accuracy of the theoretical calculation of mobility method.3.A series of new organic fused ring molecules have been designed and synthesized by introducing B,N heteroatoms into thiophene-containing fused ring framework.The calculation results showed that the introduction of BN bond didn't have effect on the aromaticity of the conjugated ring,indicating that replacing the CC double bond with BN bond was a new idea to expand the research system of organic conjugated materials.The co-crystal prepared by TCNB and NSP containing thiazolothiazole with strong electron-withdrawing group showed from the single crystal structure and spectral characterization that there were both intermolecular?-?interactions and charge transfer interactions in the co-crtstal.