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.

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.

Thanks to exciting chemical and optical features, perylene bisimide (PBI) J-aggregates\ud are ideal candidates to be employed for high-performance plastic photonic devices.\ud However, they generally tend to form - stacked H-aggregates that are unsuitable for\ud implementation in polymer resonant cavities. In this work, we demonstrate the efficient\ud compatibilization of a tailored perylene bisimide forming robust J-aggregated\ud supramolecular polymers into amorphous polypropylene. The new nanocomposite was\ud then implemented into an all-polymer planar microcavity which provides strong and\ud directional spectral redistribution of the J-aggregate photoluminescence, owing to a\ud strong modification of the photonic states. A systematic analysis of the photoemitting\ud processes, including photoluminescence decay and quantum yields, shows that the\ud optical confinement in the polymeric microcavity does not introduce any additional nonradiative\ud de-excitation pathways to those already found in the J-aggregate\ud nanocomposite film and pave the way to PBI-based high-performance plastic photonic\ud devices

An aqueous-solution-processed photoconductive cathode interlayer is developed, in which the photoinduced charge transfer brings multiple advantages such as increased conductivity and electron mobility, as well as reduced work function. Average power conversion efficiency over 10% is achieved even when the thickness of the cathode interlayer and active layer is up to 100 and 300 nm, respectively.