Exploring the mechanism of asymmetric growth of organic polar crystals: Inherent properties, specific intermolecular interactions

Organic polar crystals (OPCs) are the foundation for photonic and non-linear optical applications in advanced materials. High-quality crystals are a key in achieving efficient performance for OPCs. This work explores the properties and mechanisms of OPC growth along the polar axis. Melt microdrop growth experiments confirm that asymmetric growth is an inherent property of OPCs and relates to the intrinsic crystal structure. Notably, the solvent also plays a non-negligible role in OPCs growth. Solvent-crystal face interactions are strongly influenced by the crystal face structure. A rough surface has a slower growth rate, and a specific recognition of the solvent molecules. Asymmetric growth correlates with the modified attachment energy model and reveals the role of the solvent in inhibiting of crystal growth. Finally, the growth pattern in different solvents is explained by the interfacial adsorption model. This work will further enrich the asymmetric growth mechanism of OPCs and provide guidance for obtaining high-quality OPCs in solution.