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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Molecular Electronics and Excited State Properties I
CPP 13.4: Talk
Monday, March 17, 2025, 18:00–18:15, H38
The Influence of Solvent Nature and Annealing Conditions on the TADF Properties of DMAC-TRZ in Films and Single Crystals — •Anatolii Kuimov1, Sergey Bagnich1, Christopher Greve2, Eva M. Herzig2, and Anna Köhler1 — 1Soft Matter Optoelectronics, University of Bayreuth, Germany — 2Dynamik und Strukturbildung - Herzig Group, Universität Bayreuth, Germany
We investigated the impact of molecular arrangement and post-processing conditions on the thermally activated delayed fluorescence (TADF) of the donor-acceptor type molecule DMAC-TRZ. Specifically, we studied luminescence at various temperatures and time delays after excitation across different solid-state morphologies, including amorphous films, polycrystals, and single crystals, complemented by X-ray analysis of the single crystal. In single crystals, we observed that emission energy, the singlet-triplet gap, and TADF intensity were influenced by processing conditions, such as aging, thermal and solvent annealing, and the choice of solution for crystal growth. These effects are attributed to changes in the torsion angle between the donor and acceptor moieties. Comparisons with polycrystals and amorphous films reveal that introducing morphological disorder promotes a more orthogonal donor-acceptor arrangement, leading to a smaller singlet-triplet gap and enhanced TADF. Our findings emphasize the pivotal role of molecular conformation in modulating photophysical properties. This study highlights the potential of tailoring material performance through structural modifications and annealing strategies to optimize TADF efficiency for organic optoelectronic applications.
Keywords: Thermally Activated Delayed Fluorescence (TADF); Molecular Conformation; Singlet-Triplet Energy Gap; Post-Processing Effects; Donor-Acceptor Molecule