Unveiling novel grub-style pentacene crystals driven by hierarchical self-assembled crystallization

Abstract

Organic-semiconductor-based electronic devices have become a pivotal area of research, particularly owing to their promising applications in cost-effective and flexible electronics. Refinement of the crystalline structure of organic semiconductors is one of the most important strategies for improving device performance. Herein, we aim to expand our knowledge of single-crystalline organic semiconductors and elucidate the crystallization mechanism and growth dynamics of novel grub-shaped pentacene single crystals synthesized via a solvent-assisted drying technique. These crystals exhibit a unique grub-like morphology, distinct from the planar or ribbon-like structures typically reported for high-solubility organic semiconductors. The findings reveal that pentacene molecules, self-assembled through pi-pi interactions, form numerous small sub-grub crystals, which subsequently coalesce into larger, well-defined crystals. This hypothesis was supported by the presence of a hierarchical structure combined with sub-grub-like crystals on the grub-shaped pentacene crystal surface. Electrical evaluations demonstrated substantial current densities in the low-drain-voltage regime, underscoring the potential of these crystals for advanced organic electronic applications. This study offers significant insight into the unique crystallization behavior of low-solubility organic semiconductors and highlights their potential for use in high-performance electronics.