Study On The Synthesis And Photoelectronic Properties Of The Polymers Containing Dibenzothiophene-S,S-dioxide

The conjugated polymers in photoelectric materials have been widely used in organic light-emitting diodes because of their advantages such as lighter quality,diversified structure and high photoelectric effect.They have become a hotspot in modern and modern materials.Among them,polyfluorene-based materials are widely favored in blue polymer materials because of their good solubility and mechanical ductility,and are easy to process.However the difference between electrons and hole transport rate of polyfluorene is too large,greatly limits the application of such materials.Dibenzothiophene-S,S-dioxide is an electron withdrawing unit with high stability.All the atoms are at the highest walence,giving the SO moiety having a great anrioxidant capacity.In this thesis,aiming at the shortcomings of polyfluorene materials and the characteristics of SO unit,The S,S-dioxo-dibenzothiophene units substituted by alkyl chains,are introduced into polyfluorene to enrich the new application of SO units.At the same time,the transfer rate of electron holes can be balanced and the photoelectric properties of the materials can be greatly improved.In the second chapter,we have prepared fluorene and alkyl-substituted S,S-dioxo-dibenzo-thiophene copolymers.By changing the ratio of alkyl chains on S,S-dioxo-dibenzothiophene,the photoelectric properties of the polymer can be improved,and the solution processing performance and solubility of the material can be greatly enhanced.By adjusting the proportion of the substituents,a saturated deep blue light is obtained,exhibiting excellent spectral stability and high electroluminescence efficiency.At the same time,we also introduce a certain amount of SO groups on the main chain of polyfluorene,which greatly improves the flatness and regularity of the polymer by inducing polyfluorene β phase.By studying the induction effect of polyfluorene main chain β phase,it can not only extend the application range of SO unit,but also have some guiding significance for the structural design of related materials.In the third chapter,we designed and synthesized a copolymer of fluorene and side chain containing S,S-dioxo-dibenzo-thiophene copolymers.Between the C-9 position of fluorene,carbazole and S,S-dioxo-dibenzothiophene were respectively suspended in the alkyl chain,and the photoelectric properties were studied systematically.It was found that grafting the alkyl chain containing SO unit in the polymer side chain not only allowed the polymer to have better solution processing properties and solvent properties,but also the alkyl chain remained a certain distance between the backbone donor and the SO receptor,the charge efficiency significantly reduced due to the alkyl chain separated transmission,which play a role in restraining intra-molecular charge transport(ICT)effect.