Molecular Packing in Self-Assembled p-n and n-p-n Heterostructure Co-oligomers

The molecular packing structure in the self‐assembled p‐n and n‐p‐n heterostructure oligomers (OT₂O and T₂O₂) was investigated. The macroscopic properties of the two oligomers were systemically investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X‐ray diffraction (XRD), which revealed that the 3D (three‐dimensional) assemblies of the two oligomers exhibited obvious differences. The two‐dimensional assemblies (2D) of them were identified by scanning tunneling microscopy (STM) on a highly oriented poyrolytic graphite (HOPG) surface. Well‐ordered monolayer assembly structures were fabricated by symmetric molecules (OT₂Os), while the ordered dormain of asymmetric molecule (T₂O₂s) could not be clearly resolved. This system, as an excellent example, may provide guidance for the design of the novel p‐n heterostructure oligomer and polymer.