@article{BrustNaglerShoyamaetal.2023,
  author    = {Brust, Felix and Nagler, Oliver and Shoyama, Kazutaka and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Organic Light-Emitting Diodes Based on Silandiol-Bay-Bridged Perylene Bisimides},
  series = {Advanced Optical Materials},
  volume    = {11},
  journal   = {Advanced Optical Materials},
  number    = {5},
  doi       = {10.1002/adom.202202676},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312599},
  year      = {2023},
  abstract  = {Perylene bisimides (PBIs) are among the best fluorophores but have to be enwrapped for optoelectronic applications by large and heavy substituents to prevent their ππ-stacking, which is known to accelerate non-radiative decay processes in the solid state. Here, light-weight di-tert-butylsilyl groups are introduced to bridge 1,12-dihydroxy and 1,6,7,12-tetrahydroxy PBIs to afford sublimable dyes for vacuum-processed optoelectronic devices. For both new compounds, this substitution provides a twisted and shielded perylene π-core whose, via OSiObridges, rigid structure affords well-resolved absorption and emission spectra with strong fluorescence in solution, as well as in the solid state. The usefulness of these dyes for vacuum-processed optoelectronic devices is demonstrated in organic light-emitting diodes (OLEDs) that show monomer-like emission spectra and high maximum external quantum efficiency (EQEmax) values of up to 3.1\% for the doubly silicon-bridged PBI.},
  language  = {en}
}
@article{SchmidtStolteSuessetal.2019,
  author    = {Schmidt, David and Stolte, Matthias and S{\"u}ß, Jasmin and Liess, Dr. Andreas and Stepanenko, Vladimir and W{\"u}rthner, Frank},
  title     = {Protein-like enwrapped perylene bisimide chromophore as bright microcrystalline emitter material},
  series = {Angewandte Chemie International Edition},
  volume    = {58},
  journal   = {Angewandte Chemie International Edition},
  number    = {38},
  doi       = {10.1002/ange.201907618},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204809},
  pages     = {13385-13389},
  year      = {2019},
  abstract  = {Strongly emissive solid-state materials are mandatory components for many emerging optoelectronic technologies, but fluorescence is often quenched in the solid state owing to strong intermolecular interactions. The design of new organic pigments, which retain their optical properties despite their high tendency to crystallize, could overcome such limitations. Herein, we show a new material with monomer-like absorption and emission profiles as well as fluorescence quantum yields over 90 \% in its crystalline solid state. The material was synthesized by attaching two bulky tris(4-tert-butylphenyl)phenoxy substituents at the perylene bisimide bay positions. These substituents direct a packing arrangement with full enwrapping of the chromophore and unidirectional chromophore alignment within the crystal lattice to afford optical properties that resemble those of their natural pigment counterparts, in which chromophores are rigidly embedded in protein environments.},
  language  = {en}
}
@article{HerbstSoberatsLeowanawatetal.2018,
  author    = {Herbst, Stefanie and Soberats, Bartolome and Leowanawat, Pawaret and Stolte, Matthias and Lehmann, Matthias and W{\"u}rthner, Frank},
  title     = {Self-assembly of multi-stranded perylene dye J-aggregates in columnar liquid-crystalline phases},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-018-05018-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-319914},
  year      = {2018},
  abstract  = {Many discoid dyes self-assemble into columnar liquid-crystalline (LC) phases with packing arrangements that are undesired for photonic applications due to H-type exciton coupling. Here, we report a series of crystalline and LC perylene bisimides (PBIs) self-assembling into single or multi-stranded (two, three, and four strands) aggregates with predominant J-type exciton coupling. These differences in the supramolecular packing and optical properties are achieved by molecular design variations of tetra-bay phenoxy-dendronized PBIs with two N-H groups at the imide positions. The self-assembly is driven by hydrogen bonding, slipped π-π stacking, nanosegregation, and steric requirements of the peripheral building blocks. We could determine the impact of the packing motifs on the spectroscopic properties and demonstrate different J- and H-type coupling contributions between the chromophores. Our findings on structure-property relationships and strong J-couplings in bulk LC materials open a new avenue in the molecular engineering of PBI J-aggregates with prospective applications in photonics.},
  language  = {en}
}
@article{GilSepulcreLindnerSchindleretal.2021,
  author    = {Gil-Sepulcre, Marcos and Lindner, Joachim O. and Schindler, Dorothee and Velasco, Luc{\´i}a and Moonshiram, Dooshaye and R{\"u}diger, Olaf and DeBeer, Serena and Stepanenko, Vladimir and Solano, Eduardo and W{\"u}rthner, Frank and Llobet, Antoni},
  title     = {Surface-promoted evolution of Ru-bda coordination oligomers boosts the efficiency of water oxidation molecular anodes},
  series = {Journal of the American Chemical Society},
  volume    = {143},
  journal   = {Journal of the American Chemical Society},
  number    = {30},
  doi       = {10.1021/jacs.1c04738},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-351514},
  pages     = {11651-11661},
  year      = {2021},
  abstract  = {A new Ru oligomer of formula {[Ru-\(^{II}\)(bda-\(\kappa\)-N\(^2\)O\(^2\))(4,4'-bpy)]\(_{10}\)(4,4'-bpy)}, 10 (bda is [2,2'-bipyridine]-6,6'-dicarbox-ylate and 4,4'-bpy is 4,4'-bipyridine), was synthesized and thoroughly characterized with spectroscopic, X-ray, and electrochemical techniques. This oligomer exhibits strong affinity for graphitic materials through CH-\(\pi\) interactions and thus easily anchors on multiwalled carbon nanotubes (CNT), generating the molecular hybrid material 10@CNT. The latter acts as a water oxidation catalyst and converts to a new species, 10'(H\(_2\)O)\(_2\)@CNT, during the electrochemical oxygen evolution process involving solvation and ligand reorganization facilitated by the interactions of molecular Ru catalyst and the surface. This heterogeneous system has been shown to be a powerful and robust molecular hybrid anode for electrocatalytic water oxidation into molecular oxygen, achieving current densities in the range of 200 mA/cm\(^2\) at pH 7 under an applied potential of 1.45 V vs NHE. The remarkable long-term stability of this hybrid material during turnover is rationalized based on the supramolecular interaction of the catalyst with the graphitic surface.},
  language  = {en}
}
@article{GryszelSchlossarekWuerthneretal.2023,
  author    = {Gryszel, Maciej and Schlossarek, Tim and W{\"u}rthner, Frank and Natali, Mirco and Głowacki, Eric Daniel},
  title     = {Water-soluble cationic perylene diimide dyes as stable photocatalysts for H\(_2\)O\(_2\) evolution},
  series = {ChemPhotoChem},
  volume    = {7},
  journal   = {ChemPhotoChem},
  number    = {9},
  issn      = {2367-0932},
  doi       = {10.1002/cptc.202300070},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-370250},
  year      = {2023},
  abstract  = {Photocatalytic generation of hydrogen peroxide, H\(_2\)O\(_2\), has gained increasing attention in recent years, with applications ranging from solar energy conversion to biophysical research. While semiconducting solid-state materials are normally regarded as the workhorse for photogeneration of H\(_2\)O\(_2\), an intriguing alternative for on-demand H\(_2\)O\(_2\) is the use of photocatalytic organic dyes. Herein we report the use of water-soluble dyes based on perylene diimide molecules which behave as true molecular catalysts for the light-induced conversion of dissolved oxygen to hydrogen peroxide. In particular, we address how to obtain visible-light photocatalysts which are stable with respect to aggregation and photochemical degradation. We report on the factors affecting efficiency and stability, including variable electron donors, oxygen partial pressure, pH, and molecular catalyst structure. The result is a perylene diimide derivative with unprecedented peroxide evolution performance using a broad range of organic donor molecules and operating in a wide pH range.},
  language  = {en}
}
@article{HeWuD'Avinoetal.2018,
  author    = {He, Tao and Wu, Yanfei and D'Avino, Gabriele and Schmidt, Elliot and Stolte, Matthias and Cornil, J{\´e}r{\^o}me and Beljonne, David and Ruden, P. Paul and W{\"u}rthner, Frank and Frisbie, C. Daniel},
  title     = {Crystal step edges can trap electrons on the surfaces of n-type organic semiconductors},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-018-04479-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227957},
  year      = {2018},
  abstract  = {Understanding relationships between microstructure and electrical transport is an important goal for the materials science of organic semiconductors. Combining high-resolution surface potential mapping by scanning Kelvin probe microscopy (SKPM) with systematic field effect transport measurements, we show that step edges can trap electrons on the surfaces of single crystal organic semiconductors. n-type organic semiconductor crystals exhibiting positive step edge surface potentials display threshold voltages that increase and carrier mobilities that decrease with increasing step density, characteristic of trapping, whereas crystals that do not have positive step edge surface potentials do not have strongly step density dependent transport. A device model and microelectrostatics calculations suggest that trapping can be intrinsic to step edges for crystals of molecules with polar substituents. The results provide a unique example of a specific microstructure-charge trapping relationship and highlight the utility of surface potential imaging in combination with transport measurements as a productive strategy for uncovering microscopic structure-property relationships in organic semiconductors.},
  language  = {en}
}
@article{GoleStepanenkoRageretal.2018,
  author    = {Gole, Bappaditya and Stepanenko, Vladimir and Rager, Sabrina and Gr{\"u}ne, Matthias and Medina, Dana D. and Bein, Thomas and W{\"u}rthner, Frank and Beuerle, Florian},
  title     = {Microtubular Self-Assembly of Covalent Organic Frameworks},
  series = {Angewandte Chemie International Edition},
  volume    = {57},
  journal   = {Angewandte Chemie International Edition},
  doi       = {10.1002/anie.201708526},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227373},
  pages     = {846-850},
  year      = {2018},
  abstract  = {Despite significant progress in the synthesis of covalent organic frameworks (COFs), reports on the precise construction of template-free nano- and microstructures of such materials have been rare. In the quest for dye-containing porous materials, a novel conjugated framework DPP-TAPP-COF with an enhanced absorption capability up to λ=800 nm has been synthesized by utilizing reversible imine condensations between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and a diketopyrrolopyrrole (DPP) dialdehyde derivative. Surprisingly, the obtained COF exhibited spontaneous aggregation into hollow microtubular assemblies with outer and inner tube diameters of around 300 and 90 nm, respectively. A detailed mechanistic investigation revealed the time-dependent transformation of initial sheet-like agglomerates into the tubular microstructures.},
  language  = {en}
}
@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}
}