Blue Electroluminescence Properties Based on Thermally Activated Delayed Fluorescence Emitters Containing Diphenyl Sulfone Group

Abstract

Two blue emitter molecules were designed and synthesized based on diphenyl sulfone group (DPS) exhibiting thermally activated delayed fluorescence (TADF) characteristics for the better organic light emitting diodes (OLED) devices. DPS was for common acceptor position was combined with two different spiro-acridine groups for donor. Synthesized each materials was named DPS-D1 and DPS-D2. These molecules showed different intermolecular charge transfer (ICT) characteristics. Calculated energy band gap (ΔEst) for DPS-D1 was 0.062 eV, and DPS-D2 was 0.128 eV. There are Buchwald-Hartwig and -OH formation of cyclization reactions for all emitter synthesis. UV-Visible and solution photoluminescence (PL) spectra were obtained with three solvents (dichloromethane, toluene, and dimethylforamide), and these materials showed polarity dependence that generally indicates TADF property. Electroluminescence (EL) properties were also investigated based on general phosphorescence device structure.