@article{MuellerSpenstKagereretal.2022,
  author    = {M{\"u}ller, Ulrich and Spenst, Peter and Kagerer, Philipp and Stolte, Matthias and W{\"u}rthner, Frank and Pflaum, Jens},
  title     = {Photon-Correlation Studies on Multichromophore Macrocycles of Perylene Dyes},
  series = {Advanced Optical Materials},
  volume    = {10},
  journal   = {Advanced Optical Materials},
  number    = {14},
  doi       = {10.1002/adom.202200234},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287219},
  year      = {2022},
  abstract  = {Organic dyes offer unique properties for their application as room temperature single photon emitters. By means of photon-correlation, the emission characteristics of macrocyclic para-xylylene linked perylene bisimide (PBI) trimers and tetramers dispersed in polymethyl methacrylate matrices are analyzed. The optical data indicate that, despite of the strong emission enhancement of PBI trimers and tetramers according to their larger number of chromophores, the photon-correlation statistics still obeys that of single photon emitters. Moreover, driving PBI trimers and tetramers at higher excitation powers, saturated emission behavior for monomers is found while macrocycle emission is still far-off saturation but shows enhanced fluctuations. This observation is attributed to fast singlet-singlet annihilation, i.e., faster than the radiative lifetime of the excited S1 state, and the enlarged number of conformational arrangements of multichromophores in the polymeric host. Finally, embedding trimeric PBI macrocycles in active organic light-emitting diode matrices, electrically driven bright fluorescence together with an indication for antibunching at room temperature can be detected. This, so far, has only been observed for phosphorescent emitters that feature much longer lifetimes of the excited states and, thus, smaller radiative recombination rates. The results are discussed in the context of possible effects on the g(2) behavior of molecular emitters.},
  language  = {en}
}
@article{BoldStolteShoyamaetal.2022,
  author    = {Bold, Kevin and Stolte, Matthias and Shoyama, Kazutaka and Krause, Ana-Maria and Schmiedel, Alexander and Holzapfel, Marco and Lambert, Christoph and W{\"u}rthner, Frank},
  title     = {Macrocyclic Donor-Acceptor Dyads Composed of Oligothiophene Half-Cycles and Perylene Bisimides},
  series = {Chemistry - A European Journal},
  volume    = {28},
  journal   = {Chemistry - A European Journal},
  number    = {30},
  doi       = {10.1002/chem.202200355},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276435},
  year      = {2022},
  abstract  = {A series of donor-acceptor (D-A) macrocyclic dyads consisting of an electron-poor perylene bisimide (PBI) π-scaffold bridged with electron-rich α-oligothiophenes bearing four, five, six and seven thiophene units between the two phenyl-imide substituents has been synthesized and characterized by steady-state UV/Vis absorption and fluorescence spectroscopy, cyclic and differential pulse voltammetry as well as transient absorption spectroscopy. Tying the oligothiophene strands in a conformationally fixed macrocyclic arrangement leads to a more rigid π-scaffold with vibronic fine structure in the respective absorption spectra. Electrochemical analysis disclosed charged state properties in solution which are strongly dependent on the degree of rigidification within the individual macrocycle. Investigation of the excited state dynamics revealed an oligothiophene bridge size-dependent fast charge transfer process for the macrocyclic dyads upon PBI subunit excitation.},
  language  = {en}
}
@article{SchembriKimLiessetal.2021,
  author    = {Schembri, Tim and Kim, Jin Hong and Liess, Andreas and Stepanenko, Vladimir and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Semitransparent Layers of Social Self-Sorting Merocyanine Dyes for Ultranarrow Bandwidth Organic Photodiodes},
  series = {Advanced Optical Materials},
  volume    = {9},
  journal   = {Advanced Optical Materials},
  number    = {15},
  doi       = {10.1002/adom.202100213},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244762},
  year      = {2021},
  abstract  = {Two dipolar merocyanines consisting of the same π-conjugated chromophore but different alkyl substituents adopt very different packing arrangements in their respective solid state with either H- or J-type exciton coupling, leading to ultranarrow absorption bands at 477 and 750 nm, respectively, due to exchange narrowing. The social self-sorting behavior of these push-pull chromophores in their mixed thin films is evaluated and the impact on morphology as well as opto-electronical properties is determined. The implementation of this well-tuned two-component material with tailored optical features allows to optimize planar heterojunction organic photodiodes with fullerene ​(C\(_{60}\)) with either dual or single wavelength selectivity in the blue and NIR spectral range with ultranarrow bandwidths of only 11 nm (200 cm\(^{-1}\)) and an external quantum efficiency of up to 18\% at 754 nm under 0 V bias. The application of these photodiodes as low-power consuming heart rate monitors is demonstrated by a reflectance-mode photoplethysmography (PPG) sensor.},
  language  = {en}
}
@article{StolteHechtXieetal.2020,
  author    = {Stolte, Matthias and Hecht, Reinhard and Xie, Zengqi and Liu, Linlin and Kaufmann, Christina and Kudzus, Astrid and Schmidt, David and W{\"u}rthner, Frank},
  title     = {Crystal Engineering of 1D Exciton Systems Composed of Single- and Double-Stranded Perylene Bisimide J-Aggregates},
  series = {Advanced Optical Materials},
  volume    = {8},
  journal   = {Advanced Optical Materials},
  number    = {18},
  doi       = {10.1002/adom.202000926},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218221},
  year      = {2020},
  abstract  = {Single crystals of three at bay area tetraphenoxy-substituted perylene bisimide dyes are grown by vacuum sublimation. X-ray analysis reveals the self-assembly of these highly twisted perylene bisimides (PBIs) in the solid state via imide-imide hydrogen bonding into hydrogen-bonded PBI chains. The crystallographic insights disclose that the conformation and sterical congestion imparted by the phenoxy substituents can be controlled by ortho-substituents. Accordingly, whilst sterically less demanding methyl and isopropyl substituents afford double-stranded PBI chains of complementary P and M atropo-enantiomers, single hydrogen-bonded chains of homochiral PBIs are observed for the sterically more demanding ortho-phenyl substituents. Investigation of the absorption and fluorescence properties of microcrystals and thin films of these PBIs allow for an unambiguous interpretation of these exciton systems. Thus, the J-aggregates of the double-stranded crystals exhibit a much larger (negative) exciton coupling than the single-stranded one, which in contrast has the higher solid-state fluorescence quantum yield.},
  language  = {en}
}
@article{MenekseMahlAlbertetal.2023,
  author    = {Menekse, Kaan and Mahl, Magnus and Albert, Julius and Niyas, M. A. and Shoyama, Kazutaka and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Supramolecularly Engineered Bulk-Heterojunction Solar Cells with Self-Assembled Non-Fullerene Nanographene Tetraimide Acceptors},
  series = {Solar RRL},
  volume    = {7},
  journal   = {Solar RRL},
  number    = {2},
  doi       = {10.1002/solr.202200895},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312099},
  year      = {2023},
  abstract  = {A series of novel imide-functionalized C\(_{64}\) nanographenes is investigated as acceptor components in organic solar cells (OSCs) in combination with donor polymer PM6. These electron-poor molecules either prevail as a monomer or self-assemble into dimers in the OSC active layer depending on the chosen imide substituents. This allows for the controlled stacking of electron-poor and electron-rich π-scaffolds to establish a novel class of non-fullerene acceptor materials to tailor the bulk-heterojunction morphology of the OSCs. The best performance is observed for derivatives that are able to self-assemble into dimers, reaching power conversion efficiencies of up to 7.1\%.},
  language  = {en}
}
@article{SunAnhaltSarosietal.2022,
  author    = {Sun, Meng-Jia and Anhalt, Olga and S{\´a}rosi, Menyh{\´a}rt B. and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Activating Organic Phosphorescence via Heavy Metal-π Interaction Induced Intersystem Crossing},
  series = {Advanced Materials},
  volume    = {34},
  journal   = {Advanced Materials},
  number    = {51},
  doi       = {10.1002/adma.202207331},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312248},
  year      = {2022},
  abstract  = {Heavy-atom-containing clusters, nanocrystals, and other semiconductors can sensitize the triplet states of their surface-bonded chromophores, but the energy loss, such as nonradiative deactivation, often prevents the synergistic light emission in their solid-state coassemblies. Cocrystallization allows new combinations of molecules with complementary properties for achieving functionalities not available in single components. Here, the cocrystal formation that employs platinum(II) acetylacetonate (Pt(acac)\(_{2}\)) as a triplet sensitizer and electron-deficient 1,4,5,8-naphthalene diimides (NDIs) as organic phosphors is reported. The hybrid cocrystals exhibit room-temperature phosphorescence confined in the low-lying, long-lived triplet state of NDIs with photoluminescence (PL) quantum yield (Φ\(_{PL}\)) exceeding 25\% and a phosphorescence lifetime (τ\(_{Ph}\)) of 156 µs. This remarkable PL property benefits from the noncovalent electronic and spin-orbital coupling between the constituents.},
  language  = {en}
}
@article{RennerStolteWuerthner2020,
  author    = {Renner, Rebecca and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Self-Assembly of bowl-shaped naphthalimide-annulated corannulene},
  series = {ChemistryOpen},
  volume    = {9},
  journal   = {ChemistryOpen},
  number    = {1},
  doi       = {10.1002/open.201900291},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204396},
  pages     = {32-39},
  year      = {2020},
  abstract  = {The self-assembly of a bowl-shaped naphthalimide-annulated corannulene of high solubility has been studied in a variety of solvents by NMR and UV/Vis spectroscopy. Evaluation by the anti-cooperative K\(_2\)-K model revealed the formation of supramolecular dimers of outstanding thermodynamic stability. Further structural proof for the almost exclusive formation of dimers over extended aggregates is demonstrated by atomic force microscopy (AFM) and diffusion ordered spectroscopy (DOSY) measurements as well as by theoretical calculations. Thus, herein we present the first report of a supramolecular dimer of an annulated corannulene derivative in solution and discuss its extraordinarily high thermodynamic stability with association constants up to > 10\(^6\)M\(^-\) \(^1\) in methylcyclohexane, which is comparable to the association constants given for planar phthalocyanine and perylene bisimide dyes.},
  language  = {en}
}
@article{RennerMahlmeisterAnhaltetal.2021,
  author    = {Renner, Rebecca and Mahlmeister, Bernhard and Anhalt, Olga and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Chiral Perylene Bisimide Dyes by Interlocked Arene Substituents in the Bay Area},
  series = {Chemistry - A European Journal},
  volume    = {27},
  journal   = {Chemistry - A European Journal},
  number    = {46},
  doi       = {10.1002/chem.202101877},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249070},
  pages     = {11997 -- 12006},
  year      = {2021},
  abstract  = {A series of perylene bisimide (PBI) dyes bearing various aryl substituents in 1,6,7,12 bay positions has been synthesized by Suzuki cross-coupling reaction. These molecules exhibit an exceptionally large and conformationally fixed twist angle of the PBI π-core due to the high steric congestion imparted by the aryl substituents in bay positions. Single crystal X-ray analyses of phenyl-, naphthyl- and pyrenyl-functionalized PBIs reveal interlocked π-π-stacking motifs, leading to conformational chirality and the possibility for the isolation of enantiopure atropoisomers by semipreparative HPLC. The interlocked arrangement endows these molecules with substantial racemization barriers of about 120 kJ mol\(^{-1}\) for the tetraphenyl- and tetra-2-naphthyl-substituted derivatives, which is among the highest racemization barriers for axially chiral PBIs. Variable temperature NMR studies reveal the presence of a multitude of up to fourteen conformational isomers in solution that are interconverted via smaller activation barriers of about 65 kJ mol\(^{-1}\). The redox and optical properties of these core-twisted PBIs have been characterized by cyclic voltammetry, UV/Vis/NIR and fluorescence spectroscopy and their respective atropo-enantiomers were further characterized by circular dichroism (CD) and circular polarized luminescence (CPL) spectroscopy.},
  language  = {en}
}
@article{BoldStolteShoyamaetal.2022,
  author    = {Bold, Kevin and Stolte, Matthias and Shoyama, Kazutaka and Holzapfel, Marco and Schmiedel, Alexander and Lambert, Christoph and W{\"u}rthner, Frank},
  title     = {Macrocyclic donor-acceptor dyads composed of a perylene bisimide dye surrounded by oligothiophene bridges},
  series = {Angewandte Chemie Internationale Edition},
  volume    = {61},
  journal   = {Angewandte Chemie Internationale Edition},
  number    = {1},
  doi       = {10.1002/anie.202113598},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256569},
  year      = {2022},
  abstract  = {Two macrocyclic architectures comprising oligothiophene strands that connect the imide positions of a perylene bisimide (PBI) dye have been synthesized via a platinum-mediated cross-coupling strategy. The crystal structure of the double bridged PBI reveals all syn-arranged thiophene units that completely enclose the planar PBI chromophore via a 12-membered macrocycle. The target structures were characterized by steady-state UV/Vis absorption, fluorescence and transient absorption spectroscopy, as well as cyclic and differential pulse voltammetry. Both donor-acceptor dyads show ultrafast F{\"o}rster Resonance Energy Transfer and photoinduced electron transfer, thereby leading to extremely low fluorescence quantum yields even in the lowest polarity cyclohexane solvent.},
  language  = {en}
}
@article{KimSchembriBialasetal.2022,
  author    = {Kim, Jin Hong and Schembri, Tim and Bialas, David and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Slip-Stacked J-Aggregate Materials for Organic Solar Cells and Photodetectors},
  series = {Advanced Materials},
  volume    = {34},
  journal   = {Advanced Materials},
  number    = {22},
  doi       = {10.1002/adma.202104678},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276537},
  year      = {2022},
  abstract  = {Dye-dye interactions affect the optical and electronic properties in organic semiconductor films of light harvesting and detecting optoelectronic applications. This review elaborates how to tailor these properties of organic semiconductors for organic solar cells (OSCs) and organic photodiodes (OPDs). While these devices rely on similar materials, the demands for their optical properties are rather different, the former requiring a broad absorption spectrum spanning from the UV over visible up to the near-infrared region and the latter an ultra-narrow absorption spectrum at a specific, targeted wavelength. In order to design organic semiconductors satisfying these demands, fundamental insights on the relationship of optical properties are provided depending on molecular packing arrangement and the resultant electronic coupling thereof. Based on recent advancements in the theoretical understanding of intermolecular interactions between slip-stacked dyes, distinguishing classical J-aggregates with predominant long-range Coulomb coupling from charge transfer (CT)-mediated or -coupled J-aggregates, whose red-shifts are primarily governed by short-range orbital interactions, is suggested. Within this framework, the relationship between aggregate structure and functional properties of representative classes of dye aggregates is analyzed for the most advanced OSCs and wavelength-selective OPDs, providing important insights into the rational design of thin-film optoelectronic materials.},
  language  = {en}
}