Dimensional Control in Contorted Aromatic Materials

Abstract

This Account details key developments in dimensional control of contorted aromatics for organic electronics. Coronene, perylene, pyrene, and [4]helicene, which are fragments of graphene, can be contorted using facile synthetic chemistry into large nanoribbons and nano‐architectures. In comparing contorted or higher‐dimensional graphene architectures to planar or lower‐dimensional species, the materials properties are reliably enhanced for the contorted aromatics. Examples of enhanced properties include optical absorptivity, conductivity, device photoconversion efficiency, and solubility. These enhancements are exemplified in organic photovoltaics, photodetectors, field effect transistors, and perovskite solar cells. Described herein are key advances in dimensional control of contorted aromatics that have resulted in world record photoconversion efficiencies, photodetection capabilities matching inorganic state‐of‐the‐art devices, and ∼5 nm long ultrathin soluble graphene nanoribbons.

D–π–D molecular semiconductors for perovskite solar cells: the superior role of helical versus planar π-linkers

“…6 Contorting the molecules allows new types of intermolecular contacts to emerge and in some cases can enhance intermolecular charge transfer. 7 In particular, racemic helicenes have great potential for the growth of single crystals featuring multi-dimensional charge transport. In 2004, Rajca et al reported a racemic single crystal of thia [7] helicene, with the characteristic of two-dimensional charge transport.…”

“…7 In particular, racemic helicenes have great potential for the growth of single crystals featuring multi-dimensional charge transport. In 2004, Rajca et al reported a racemic single crystal of thia [7] helicene, with the characteristic of two-dimensional charge transport. 8 In 2015, Itami et al synthesized a double helicene with three-dimensional lamellar packing.…”

Helical Nanographenes Containing an Azulene Unit: Synthesis, Crystal Structures, and Properties

“…Contorted polycyclic aromatic hydrocarbons (PAHs, or nanographenes) have received considerable attention in the past decades because of their intriguing optoelectronic properties and applications in organic electronics . Among the contorted PAHs, helicenes represent an important class of compounds because of their unique nonplanarity, inherent chirality, and dynamic behavior .…”

Rubicene, an Unusual Contorted Core for Discotic Liquid Crystals

“…[45,46] The contorted π-conjugated molecules have been identified as ideal receptors of molecular recognition. [47] The co-assembled structures of these contorted systems with spherical molecules have been very well documented in the literature. [48] Helicenes are one of the best examples of the contorted core.…”

“…The literature has reported that the co‐assembly involving curved π‐fused systems and electron‐deficient systems display promising photovoltaic effect [43,44] and OLEDs [45,46] . The contorted π‐conjugated molecules have been identified as ideal receptors of molecular recognition [47] . The co‐assembled structures of these contorted systems with spherical molecules have been very well documented in the literature [48] .…”