Luminescent distyrylbenzenes: tailoring molecular structure and crystalline morphology

The last few years have seen a steady increase in small molecule based conjugated materials, which promise innovative (opto)electronic applications. This requires however a systematic understanding of structure-property relationships, which can only be achieved via libraries of structurally well-defined single crystalline materials based on systematically designed molecular structures. In this feature article, we are presenting structure-property relationships of functionalized distyrylbenzene (DSB), which is one of the most extensively investigated pi-conjugated molecular materials. This will provide a general insight into the specific implications of intermolecular arrangements on their solid state optoelectronic properties, discussing H-vs. J-aggregation, herringbone vs. pi-stacks, the occurrence of excimers, size effects, and polycrystallinity. The systematic insight into DSB functionalization will then suggest pathways towards targeted molecular design strategies, with special focus on the cyano-vinylene motif (DCS materials) which allows for highly fluorescence solid state samples due to synergetic packing effects promoted by its twist elasticity and secondary bonding interaction. Finally, recent advances in the application of DSB-/DCS-based materials are shortly reviewed.