Two-dimensional Fused Polyaromatics Based On Perylenedimide: Conformation Tuning And Opto-physical Properties

Organic two-dimensional conjugated materials(polycyclic aromatic hydrocarbons,PAHs)have attracted increasing attention due to their unique extended ?-conjugated structure and excellent photoelectronic properties.Their rigid ?-skeletong and planar molecular surface will benefit their molecular stacking in solid state,further offer PAHs high mobilitis.Thus,it is very hot research field to exploit numerous PAHs for applications,such as organic light-emitting diodes,organic thin-film transistors,organic photovoltaics,and other bio-medicinal applications.However,the strong ?-? stacking will be detrimental to their photoluminescence and induce poor solubility.It is necessary to introduce peripheral bulky substitutes,so as to provide molecular steric hindrance and to suppress their stacking in concentrated solutions or solid film.Yet,this strategy is not very easy due to the synthetic methodology limitation.Perylenedimide(PDIs)derivatives possesses deep HOMO and the LUMO energy levels of ca-3.8 e V,and PDI derivatives as N-type semiconductors.In dilute solution,PDI derivatives always exhibit good photoluminescence,while in solid state,aggregate-induced fluorescence quenching will deteriment their possible application as emitters for bio-probes.In addition,the eight C-H positions on PDI unit are ready to be modified with other building blocks.So,there are lots of chemical derivatives have been developed by using PDI as the starting materials.With all these considerations in mind,we tried to exploit novel PDI-base polyaromatics with contorted chemical structures and high PLQY in solid field.We also tried to find their preliminary applications in OPVs and biological systems.The main contents of this thesis follows:(1)The heterocyclic aromatic dithienocarbazole(DTC)with high carrier mobility is selected as the linking unit,and the two alkylated perylene imide(PDI)monomers are connected through the Stille coupling reaction to obtain the non-fullerene acceptor(NFA)DTC-PDI,and on this basis,a fully fused NFA FDTC-PDI is obtained through DDQ intramolecular dehydrogenation and cyclization reaction.The intramolecular cyclization reaction increases molecular conjugation,free charge can be delocalized in a larger range,and the enhanced intermolecular ?-? stacking effectively improves the charge transport performance.The introduction of alkyl chains improves the solubility of molecules and regulates the morphology of aggregation.(2)Using perylene molecules as raw materials,try to introduce a non-six-membered ring structure into the conjugated system to enrich the twisted fused-ring molecular system.Most fused ring systems are all-carbon materials.In this work,we try to introduce different heteroatoms such as S,Se,O,B,etc.into the fused ring system to construct a new fused ring molecule and hope that the relative performance of this type of material is further improved.The cyclization of heteroatoms in the Gulf region allows HTTP-N,HTTP-S,and HTTP-Se to have more planar PDI subunits,which may help electron transmission.In addition,because the five-membered ring constructed by heteroatoms has the ability to donate electrons,compared with 4,9-Py-PDI,HTTP-N,HTTP-S and HTTP-Se have higher LUMO energy levels,which is beneficial to increase Voc.HTTP-N,HTTP-S and HTTP-Se can provide a new design strategy for constructing high-performance NFAs.