Design,Synthesis And Performance Study Of Diphenyl Sulfone-Based Thermally Activated Delayed Fluorescent Materials

Thermally activated delayed fluorescence（TADF）material are a new generation of highly efficient organic light emitting materials following the first generation of fluorescent and second generation of phosphorescent materials.TADF materials can transfer triplet excitons to single excitons through reverse intersystem crossing under the condition of thermal excitation,and achieve 100%internal quantum efficiency without the use of rare metals.This kind of high efficiency and low cost materials has a broad prospect and wide application value.Therefore,the design and synthesis of TADF molecule has become one of the research hotspots.At present,red TADF materials and green TADF materials have been well developed,while efficient blue TADF materials still have some defects,which need to be more studied.This thesis mainly focuses on the design and synthesis of TADF molecules based on diphenyl sulfone-acridine skeleton,and discusses the relationship between structure and properties.The structure is determined by nuclear magnetic resonance spectroscopy and single crystal diffraction.The molecular orbital energy level and electron cloud density distribution were optimized by density functional theory calculation.The photophysical properties of the compounds were analyzed and discussed by UV-VIS spectrum,steady-state/transient spectrum,electrochemical testing,electrochemiluminescence testing and chemiluminescence testing.The research contents are as follows:（1）A series of D-A TADF molecules were designed and synthesized by using diphenyl sulfone-acridine as the skeleton and selecting several groups with different electron supplying properties（methoxy,methyl,trifluoromethyl,cyanide）as substituents.DMAC-DPS-OMe,DMAC-DPS-CH₃,DMAC-DPS-H,DMAC-DPS-CF₃,DMAC-DPS-2CF₃,and DMAC-DPS-CN.The effects of different substituents on the molecular skeleton and its luminescence properties were investigated.The results showed that the stronger the electron donor ability of the substituents,the better the luminescence performance of the series of compounds,and the properties of aggregation-induced luminescence enhancement,when the water doping ratio is high enough,the luminescence intensity can be significantly enhanced.（2）A series of TADF molecules were designed and synthesized by modifying the framework of diphenyl sulfone–spiro acridine and diphenyl sulfone-acridine respectively through methoxy,methyl and hydroxyl groups that may cause hydrogen bonding.SBA-2DPS-4OMe,SBA-2DPS-2OMe,SBA-2DPS-t Bu Ph,DMAC-DPS-2OMe,SBA-2DPS-4OH,DMAC-DPS-2OH.The compound with spiro acridine as donor showed better luminescence properties than acridine.Compound SBA-2DPS-2OMe showed weak electrochemical luminescence and good chemiluminescence,with an efficiency of 0.00235%.The chemiluminescence efficiency of compound SBA-2DPS-t Bu Ph is 0.00397%（3）A series of TADF molecules were designed and synthesized by using diphenyl sulfone-acridine as the framework and by introducing ions into substituents.10-channel DMAC-DPS-Di（n-Bu）,[DMAC-DPS-Di（Im⁺）][BF₄^-],[DMAC-DPS-Di（Im⁺）][PF₆^-],[DMAC-DPS-Di（Im⁺）][I^-],[DMAC-DPS-Di（Im⁺）][TFSI^-],[DMAC-DPS-Di（Im⁺）][FSI^-].The introduction of ions can control the emission wavelength and luminous region of the luminescent materials.