@article{HocheSchulzDietrichetal.2019,
  author    = {Hoche, Joscha and Schulz, Alexander and Dietrich, Lysanne Monika and Humeniuk, Alexander and Stolte, Matthias and Schmidt, David and Brixner, Tobias and W{\"u}rthner, Frank and Mitric, Roland},
  title     = {The origin of the solvent dependence of fluorescence quantum yields in dipolar merocyanine dyes},
  series = {Chemical Science},
  volume    = {10},
  journal   = {Chemical Science},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-198707},
  pages     = {11013},
  year      = {2019},
  abstract  = {Fluorophores with high quantum yields are desired for a variety of applications. Optimization of promising chromophores requires an understanding of the non-radiative decay channels that compete with the emission of photons. We synthesized a new derivative of the famous laser dye 4-dicyanomethylen-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM),i.e., merocyanine 4-(dicyanomethylene)-2-tert-butyl-6-[3-(3-butyl-benzothiazol-2-ylidene)1-propenyl]-4H-pyran (DCBT). We measured fluorescence lifetimes and quantum yields in a variety of solvents and found a trend opposite to the energy gap law.This motivated a theoretical investigation into the possible non-radiative decay channels. We propose that a barrier to a conical intersection exists that is very sensitive to the solvent polarity. The conical intersection is characterized by a twisted geometry which allows a subsequent photoisomerization. Transient absorption measurements confirmed the formation of a photoisomer in unpolar solvents, while the measurements of fluorescence quantum yields at low temperature demonstrated the existence of an activation energy barrier.},
  language  = {en}
}
@article{FarrellGrandeSchmidtetal.2019,
  author    = {Farrell, Jeffrey M. and Grande, Vincenzo and Schmidt, David and W{\"u}rthner, Frank},
  title     = {A Highly Warped Heptagon-Containing sp\(^2\) Carbon Scaffold via Vinylnaphthyl π-Extension},
  series = {Angewandte Chemie International Edition},
  volume    = {58},
  journal   = {Angewandte Chemie International Edition},
  number    = {46},
  doi       = {10.1002/anie.201909975},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206682},
  pages     = {16504-16507},
  year      = {2019},
  abstract  = {A new strategy is demonstrated for the synthesis of warped, negatively curved, all-sp\(^2\)-carbon π-scaffolds. Multifold C-C coupling reactions are used to transform a polyaromatic borinic acid into a saddle-shaped polyaromatic hydrocarbon (2 ) bearing two heptagonal rings. Notably, this Schwarzite substructure is synthesized in only two steps from an unfunctionalized alkene. A highly warped structure of 2 was revealed by X-ray crystallographic studies and pronounced flexibility of this π-scaffold was ascertained by experimental and computational studies. Compound 2 exhibits excellent solubility, visible range absorption and fluorescence, and readily undergoes two reversible one-electron oxidations at mild potentials.},
  language  = {en}
}
@article{WenNowakKrolNagleretal.2019,
  author    = {Wen, Xinbo and Nowak-Kr{\´o}l, Agnieszka and Nagler, Oliver and Kraus, Felix and Zhu, Na and Zheng, Nan and M{\"u}ller, Matthias and Schmidt, David and Xie, Zengqi and W{\"u}rthner, Frank},
  title     = {Tetrahydroxy-perylene bisimide embedded in zinc oxide thin film as electron transporting layer for high performance non-fullerene organic solar cells},
  series = {Angewandte Chemie International Edition},
  volume    = {58},
  journal   = {Angewandte Chemie International Edition},
  number    = {37},
  doi       = {10.1002/anie.201907467},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204723},
  pages     = {13051-13055},
  year      = {2019},
  abstract  = {By introduction of four hydroxy (HO) groups into the two perylene bisimide (PBI) bay areas, new HO-PBI ligands were obtained which upon deprotonation can complex ZnII ions and photosensitize semiconductive zinc oxide thin films. Such coordination is beneficial for dispersing PBI photosensitizer molecules evenly into metal oxide films to fabricate organic-inorganic hybrid interlayers for organic solar cells. Supported by the photoconductive effect of the ZnO:HO-PBI hybrid interlayers, improved electron collection and transportation is achieved in fullerene and non-fullerene polymer solar cell devices, leading to remarkable power conversion efficiencies of up to 15.95 \% for a non-fullerene based organic solar cell.},
  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}
}