@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{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{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} } @article{HeStolteBurschkaetal.2015, author = {He, Tao and Stolte, Matthias and Burschka, Christian and Hansen, Nis Hauke and Musiol, Thomas and K{\"a}lblein, Daniel and Pflaum, Jens and Tao, Xutang and Brill, Jochen and W{\"u}rthner, Frank}, title = {Single-crystal field-effect transistors of new Cl\(_{2}\)-NDI polymorph processed by sublimation in air}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, number = {5954}, doi = {10.1038/ncomms6954}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149255}, year = {2015}, abstract = {Physical properties of active materials built up from small molecules are dictated by their molecular packing in the solid state. Here we demonstrate for the first time the growth of n-channel single-crystal field-effect transistors and organic thin-film transistors by sublimation of 2,6-dichloro-naphthalene diimide in air. Under these conditions, a new polymorph with two-dimensional brick-wall packing mode (\(\beta\)-phase) is obtained that is distinguished from the previously reported herringbone packing motif obtained from solution (\(\alpha\)-phase). We are able to fabricate single-crystal field-effect transistors with electron mobilities in air of up to 8.6 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\) (\(\alpha\)-phase) and up to 3.5 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\) (\(\beta\)-phase) on n-octadecyltriethoxysilane-modified substrates. On silicon dioxide, thin-film devices based on \(\beta\)-phase can be manufactured in air giving rise to electron mobilities of 0.37 cm\(^{2}\)V\(^{-1}\)s\(^{-1}\). The simple crystal and thin-film growth procedures by sublimation under ambient conditions avoid elaborate substrate modifications and costly vacuum equipment-based fabrication steps.}, 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{HechtLeowanawatGerlachetal.2020, author = {Hecht, Markus and Leowanawat, Pawaret and Gerlach, Tabea and Stepanenko, Vladimir and Stolte, Matthias and Lehmann, Matthias and W{\"u}rthner, Frank}, title = {Self-Sorting Supramolecular Polymerization: Helical and Lamellar Aggregates of Tetra-Bay-Acyloxy Perylene Bisimide}, series = {Angewandte Chemie International Edition}, volume = {59}, journal = {Angewandte Chemie International Edition}, number = {39}, doi = {10.1002/anie.202006744}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224586}, pages = {17084 -- 17090}, year = {2020}, abstract = {A new perylene bisimide (PBI), with a fluorescence quantum yield up to unity, self-assembles into two polymorphic supramolecular polymers. This PBI bears four solubilizing acyloxy substituents at the bay positions and is unsubstituted at the imide position, thereby allowing hydrogen-bond-directed self-assembly in nonpolar solvents. The formation of the polymorphs is controlled by the cooling rate of hot monomer solutions. They show distinctive absorption profiles and morphologies and can be isolated in different polymorphic liquid-crystalline states. The interchromophoric arrangement causing the spectral features was elucidated, revealing the formation of columnar and lamellar phases, which are formed by either homo- or heterochiral self-assembly, respectively, of the atropoenantiomeric PBIs. Kinetic studies reveal a narcissistic self-sorting process upon fast cooling, and that the transformation into the heterochiral (racemic) sheetlike self-assemblies proceeds by dissociation via the monomeric state.}, 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{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{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{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} }