@article{DostalFennelKochetal.2018,
  author    = {Dost{\´a}l, Jakub and Fennel, Franziska and Koch, Federico and Herbst, Stefanie and W{\"u}rthner, Frank and Brixner, Tobias},
  title     = {Direct observation of exciton-exciton interactions},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-018-04884-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226271},
  year      = {2018},
  abstract  = {Natural light harvesting as well as optoelectronic and photovoltaic devices depend on efficient transport of energy following photoexcitation. Using common spectroscopic methods, however, it is challenging to discriminate one-exciton dynamics from multi-exciton interactions that arise when more than one excitation is present in the system. Here we introduce a coherent two-dimensional spectroscopic method that provides a signal only in case that the presence of one exciton influences the behavior of another one. Exemplarily, we monitor exciton diffusion by annihilation in a perylene bisimide-based J-aggregate. We determine quantitatively the exciton diffusion constant from exciton-exciton-interaction 2D spectra and reconstruct the annihilation-free dynamics for large pump powers. The latter enables for ultrafast spectroscopy at much higher intensities than conventionally possible and thus improves signal-to-noise ratios for multichromophore systems; the former recovers spatio-temporal dynamics for a broad range of phenomena in which exciton interactions are present.},
  language  = {en}
}
@article{OuyangRueheZhangetal.2022,
  author    = {Ouyang, Guanghui and R{\"u}he, Jessica and Zhang, Yang and Lin, Mei-Jin and Liu, Minghua and W{\"u}rthner, Frank},
  title     = {Intramolecular Energy and Solvent-Dependent Chirality Transfer within a BINOL-Perylene Hetero-Cyclophane},
  series = {Angewandte Chemie International Edition},
  volume    = {61},
  journal   = {Angewandte Chemie International Edition},
  number    = {31},
  doi       = {10.1002/anie.202206706},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318818},
  year      = {2022},
  abstract  = {Multichromophoric macrocycles and cyclophanes are important supramolecular architectures for the elucidation of interchromophoric interactions originating from precise spatial organization. Herein, by combining an axially chiral binaphthol bisimide (BBI) and a bay-substituted conformationally labile twisted perylene bisimide (PBI) within a cyclophane of well-defined geometry, we report a chiral PBI hetero-cyclophane (BBI-PBI) that shows intramolecular energy and solvent-regulated chirality transfer from the BBI to the PBI subunit. Excellent spectral overlap and spatial arrangement of BBI and PBI lead to efficient excitation energy transfer and subsequent PBI emission with high quantum yield (80-98 \%) in various solvents. In contrast, chirality transfer is strongly dependent on the respective solvent as revealed by circular dichroism (CD) spectroscopy. The combination of energy and chirality transfer affords a bright red circularly polarized luminescence (CPL) from the PBI chromophore by excitation of BBI.},
  language  = {en}
}
@article{MatthesSchoenfeldZottnicketal.2015,
  author    = {Matthes, Philipp R. and Sch{\"o}nfeld, Fabian and Zottnick, Sven H. and M{\"u}ller-Buschbaum, Klaus},
  title     = {Post-synthetic shaping of porosity and crystal structure of Ln-Bipy-MOFs by thermal treatment},
  series = {Molecules},
  volume    = {20},
  journal   = {Molecules},
  doi       = {10.3390/molecules200712125},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148404},
  pages     = {12125-12153},
  year      = {2015},
  abstract  = {The reaction of anhydrous lanthanide chlorides together with 4,4'-bipyridine yields the MOFs \(^{2}\)\(_{∞}\)[Ln\(_{2}\)Cl\(_{6}\)(bipy)\(_{3}\)]*2bipy, with Ln = Pr-Yb, bipy = 4,4'-bipyridine, and \(^{3}\)\(_{∞}\)[La\(_{2}\)Cl\(_{6}\)(bipy)\(_{5}\)]*4bipy. Post-synthetic thermal treatment in combination with different vacuum conditions was successfully used to shape the porosity of the MOFs. In addition to the MOFs microporosity, a tuneable mesoporosity can be implemented depending on the treatment conditions as a surface morphological modification. Furthermore, thermal treatment without vacuum results in several identifiable crystalline high-temperature phases. Instead of collapse of the frameworks upon heating, further aggregation under release of bipy is observed. \(^{3}\)\(_{∞}\)[LaCl\(_{3}\)(bipy)] and \(^{2}\)\(_{∞}\)[Ln\(_{3}\)Cl\(_{9}\)(bipy)\(_{3}\)], with Ln = La, Pr, Sm, and \(^{1}\)\(_{∞}\)[Ho\(_{2}\)Cl\(_{6}\)(bipy)\(_{2}\)] were identified and characterized, which can also exhibit luminescence. Besides being released upon heating, the linker 4,4'-bipyridine can undergo activation of C-C bonding in ortho-position leading to the in-situ formation of 4,4':2',2 '':4 '',4'''-quaterpyridine (qtpy). qtpy can thereby function as linker itself, as shown for the formation of the network \(^{2}\)\(_{∞}\)[Gd\(_{2}\)Cl\(_{6}\)(qtpy)\(_{2}\)(bipy)\(_{2}\)]*bipy. Altogether, the manuscript elaborates the influence of thermal treatment beyond the usual activation procedures reported for MOFs.},
  language  = {en}
}