Synthesis And Characterization Of Thermally Activated Delayed Fluorescent Materials Based On Dimethylacridine And Benzophenone

Organic light-emitting diodes(OLEDs)as new generation display devices have received extensive attention and applications due to their self-luminous,wide chromaticity,and flexible characteristics.The triplet state excitons can be converted into singlet excitons by reverse intersystem crossing in thermally activated delayed fluorescence(TADF)materials,so that the triplet state excitons are also effectively used,thereby achieving 100%internal quantum efficiency.TADF materials can also be pure organic structures without the heavy metals.The research on the synthesis of TADF materials and related mechanisms has become a current research hotspot due to the above advantages.In this thesis,a TADF molecule with D-A structure using dimethylacridine(DMAC)as the donor and benzophenone(BP)as the acceptor is designed and synthesized.The triphenylphosphine oxy group is introduced into the molecule to improve the electron transport efficiency.The HOMO and LUMO of this molecule has separated,and there is a twisted conformation in space.Therefore,the singlet energy and triplet energy of this molecule are Es=2.81 eV and ET=2.74 eV.The energy level difference ?EST is 0.07 eV.The low ?EST can effectively promote the reverse intersystem crossing process of triplet excitons which improves luminous efficiency.The LUMO energy level of this molecule is-2.59 eV and the HOMO energy level is-5.39 eV according to the cyclic voltammetry test.Three polysiloxanes containing TADF units were prepared.It can be seen that the TADF group still has a separated electron cloud distribution and twisted conformation in the polymers through Gaussian simulation.