Additive-Assisted Perylene Polymorphism Controlled via Secondary Bonding Interactions

The influence of molecular additives or impurities on crystal growth, morphology, and polymorphism has broad importance in various fields of material science and pharmaceutical engineering. There are numerous examples demonstrating the effect of impurities on the crystallization of pharmaceutical substances; however, systematic studies on the additives’ effect on crystallization and properties of organic semiconductors have not yet been reported. Here, we studied additive-assisted crystallization of a model aromatic hydrocarbon compound–perylene–to elaborate the crystal engineering tool for organic optoelectronics and to reveal the underlying mechanism. Anthracene, tetracene, 9,10-diphenylanthracene, and rubrene were used as representative additives. We found the optimal additive and conditions for perylene crystallization allowing us to control its polymorphic outcome. The addition of 9,10-diphenylanthracene was demonstrated to lead to a preferable crystallization of metastable β-form of perylene, whereas in the neat conditions, α-form was typically obtained as a stable one. The crystallization of perylene with 9,10-diphenylanthracene in high concentrations resulted in their stoichiometric co-crystallization. The perylene:9,10-diphenylanthracene co-crystal structure and optoelectronic properties were evaluated. The co-crystal demonstrated a photoluminescence quantum yield of 45% and hole mobility of 0.025 cm 2 /V s. The co-crystal structure analysis pointed on the stabilization of herringbone packing of perylene by interlayer C–H···π interactions, allowing the 9,10-diphenylanthracene layers to serve as the template for perylene β-polymorph nucleation. The results obtained could serve as the basis for crystallization control and engineering of high-performance materials in organic optoelectronics.