2025

Ruoko, Tero Petri; Stoeckel, Marc Antoine; Puttreddy, Rakesh; Yang, Chi Yuan; Zhang, Silan; Wu, Ziang; Candeias, Nuno R.; Samorì, Paolo; Woo, Han Young; Fabiano, Simone; Priimagi, Arri

The solid-state structure and morphology of organic semiconductors are critical in determining the performance of organic electronic devices, as they directly influence charge carrier mobility. Improved molecular packing and ordering are key to achieving better device performance. While halogen bonding (XB) has been extensively used in supramolecular crystal engineering, its potential for organic electronics remains largely untapped. Here, we show that strong and directional XB can significantly enhance the morphology and optoelectronic properties of pyridine-substituted naphthalene diimide (NDI) derivatives. By employing various XB donors with differing interaction strengths and comparing them to a non-bonding reference compound, we achieve a two-orders-of-magnitude improvement in field-effect mobility and ION-IOFF ratio. Furthermore, the geometric substitution pattern of the XB donors is found to strongly influence molecular packing, crystalline domain formation, and, ultimately, device performance.