Design,Synthesis And Photoelectric Properties Study Of Red Fluorescent Materials Based On Phenothiazine As Electron Donor

In recent years,the development and application of organic conjugated materials are improving various aspects of people's lives.By summarizing the results of previous researchers,it has been found that organic donor-acceptor molecules play a pivotal role in multi-stimulus responsive materials and organic electroluminescent device(OLED)luminescent layer materials.Based on this,we chose the"butterfly type"approximately planar phenothiazine as the donor,the benzothiadiazole group as the acceptor,and the conjugated structure was added by bonding different groups.We designed and synthesized a series of red fluorescent materials named PBTPA,PBTPE and PBDPTH.These red fluorescent materials with small twist angles are systematically explored for their photoluminescence properties and electroluminescence properties,which paved the way for further study of the structure-effect relationship between the structure and the performance.1.The three materials'(PBTPA,PBTPE and PBDPTH)photoluminescence properties were studied.They emit fluorescence at 638 nm,628 nm and 633 nm in toluene solution,respectively.They not only have AEE properties,but also have a piezfluorochromic property.Under the stimulation of chemical reagents,heat and force,the fluorescence emission wavelengths periodically change and recover,and they are all excellent performance of piezochromic aggregation induced luminescence(PAIE)materials.They are also a kind of multi-stimulation responsive materials.We demonstrate that this series of properties is inseparable from the bonding mode of the donner and acceptor,the torsion angle,and the structure of the aggregate state through DSC,XRD,DFT.2.We have conducted deeply research on materials from the perspective of electroluminescence.The electrochemical properties,excited orbital simulation calculations,solvation data models and photophysical properties of vapor deposited films were detected.We found that they both have the high radiation transition rate based on localized(LE)states and the big transition dipole moment based on charge transfer(CT)state and their excited states are all HLCT states.The external quantum efficiencies of pure organic electroluminescent devices with molecular PBTPE and PBTPA as luminescent layers can reach 1.54%and 1.62%,the maximum brightness can reach 530cd/m~2 and 585 cd/m~2,the maximum emission wavelength of electroluminescence is 658nm and 654 nm,and the exciton utilization rate is as high as 28.2%and 50%,respectively.It breaks the upper limit of 25%of the singlet exciton utilization of the spin statistical rule.They are non-doped OLED with high efficiency and high exciton utilization.Our work in this paper provides a practical basis for obtaining red light materials with high efficiency and high exciton utilization by using the HLCT mechanism.