@article{SolDehmHechtetal.2018, author = {Sol, Jeroen A. H. P. and Dehm, Volker and Hecht, Reinhard and W{\"u}rthner, Frank and Schenning, Albertus P. H. J. and Debije, Michael G.}, title = {Temperature-Responsive Luminescent Solar Concentrators: Tuning Energy Transfer in a Liquid Crystalline Matrix}, series = {Angewandte Chemie International Edition}, volume = {57}, journal = {Angewandte Chemie International Edition}, doi = {10.1002/anie.201710487}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238778}, pages = {1030-1033}, year = {2018}, abstract = {Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the F{\"o}rster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive; while after heating to a temperature above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC. The device has been shown to be highly stable towards consecutive heating and cooling cycles, making it an appealing device for harvesting otherwise unused solar energy.}, language = {en} } @article{GarainShoyamaGinderetal.2024, author = {Garain, Swadhin and Shoyama, Kazutaka and Ginder, Lea-Marleen and S{\´a}rosi, Menyh{\´a}rt and W{\"u}rthner, Frank}, title = {The delayed box: biphenyl bisimide cyclophane, a supramolecular nano-environment for the efficient generation of delayed fluorescence}, series = {Journal of the American Chemical Society}, volume = {146}, journal = {Journal of the American Chemical Society}, number = {31}, issn = {0002-7863}, doi = {10.1021/jacs.4c07730}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-370385}, pages = {22056-22063}, year = {2024}, abstract = {Activating delayed fluorescence emission in a dilute solution via a non-covalent approach is a formidable challenge. In this report, we propose a strategy for efficient delayed fluorescence generation in dilute solution using a non-covalent approach via supramolecularly engineered cyclophane-based nanoenvironments that provide sufficient binding strength to π-conjugated guests and that can stabilize triplet excitons by reducing vibrational dissipation and lowering the singlet-triplet energy gap for efficient delayed fluorescence emission. Toward this goal, a novel biphenyl bisimide-derived cyclophane is introduced as an electron-deficient and efficient triplet-generating host. Upon encapsulation of various carbazole-derived guests inside the nanocavity of this cyclophane, emissive charge transfer (CT) states close to the triplet energy level of the biphenyl bisimide are generated. The experimental results of host-guest studies manifest high association constants up to 10\(^4\) M\(^{-1}\) as the prerequisite for inclusion complex formation, the generation of emissive CT states, and triplet-state stabilization in a diluted solution state. By means of different carbazole guest molecules, we could realize tunable delayed fluorescence emission in this carbazole-encapsulated biphenyl bisimide cyclophane in methylcyclohexane/carbon tetrachloride solutions with a quantum yield (QY) of up to 15.6\%. Crystal structure analyses and solid-state photophysical studies validate the conclusions from our solution studies and provide insights into the delayed fluorescence emission mechanism.}, language = {en} }