Thermal growth of organic supramolecular crystals with screw dislocations

We report here a simple pathway to thermally assemble acene-based molecules into large crystals without modification of their chemical structures. Differential scanning calorimetry was used to characterize properly thermal events occurring during successive heating and cooling processes. More interestingly, observations by means of polarized light microscopy (POM) revealed that a spontaneous formation of screw dislocations within crystals during the isothermal treatment triggered a structural reorganization by forming large and well-defined spiral architectures. After this reorganization, new crystals showed an excellent ordering in both vertical and horizontal directions. Due to the richness in pi-electrons of acene-based molecules, we expect this work of importance to organic electronics, especially in the design of new molecular building blocks and investigation of their assembly into sophisticated supramolecular structures.