Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

• DOI: 10.1002/adfm.202207324
• Publication Date: 2022-09-22T13:34:47Z
• Authors: Parisa Sharif; Eda Alemdar; Soner Ozturk; Omer Caylan; Tugba Haciefendioglu; Goknur Buke; Murat Aydemir; Andrew Danos; Andrew P. Monkman; Erol Yildirim; Gorkem Gunbas; Ali Cirpan; Ahmet Oral
• Keywords: Intersystem crossing; Indium tin oxide

Abstract Observation of thermally activated delayed fluorescence (TADF) in conjugated systems redefined the molecular design approach to realize highly efficient organic light emitting diodes (OLEDs) early 2010s. Enabling effective reverse intersystem crossing (RISC) by minimizing difference between singlet and triplet excited state energies (Δ E ST ) is proven be a widely applicable fruitful approach, which results remarkable external quantum efficiencies (EQE). The efficacy RISC these mainly dictated first‐order mixing coefficient (λ), proportional spin‐orbit coupling (H SO inversely Δ . While has been focus OLED community over last decade, effect H largely overlooked. Here, with increased are designed synthesized substituting selected heteroatoms high‐performance TADF materials heavy‐atom selenium. A new series multicolor EQEs achieved. One materials, SeDF‐B, pure blue emission approaching 20%. Additionally, flexible graphene‐based electrodes developed for OLEDs revealed have similar performance as standard indium tin oxide (ITO) most cases. These devices first report based that utilize anodes.