Facet-Selective Growth of Heterostructured Molecular Crystals Enabled by a Solid-Solution-Mediated Strategy

Area of Science:

• Materials Science
• Crystallography
• Supramolecular Chemistry

Background:

• Constructing heterojunction interfaces in molecular crystals is challenging due to lattice parameter and packing mismatches.
• These mismatches destabilize interfaces, limiting heteroepitaxy between different molecular crystals.

Purpose of the Study:

• To develop a strategy for creating heterostructured molecular crystals from components that do not typically form heterojunctions.
• To overcome interfacial lattice mismatches using a solid-solution-mediated approach.

Main Methods:

• On-seed-surface crystallization using Fe(II) and Co(II) complexes.
• Employing solid-solution crystals as secondary components to achieve lattice matching with a seed crystal.
• Systematic variation of the Fe(II)/Co(II) feed ratio and analysis of resulting crystal structures.

Main Results:

• Direct heteroepitaxy failed due to significant lattice mismatch between Fe(II) and Co(II) complexes.
• Solid-solution crystals facilitated lattice matching, enabling the formation of core-shell and dumbbell-like heterostructured crystals.
• Facet-selective crystallization was achieved by controlling the solid-solution composition, leading to anisotropic lattice mismatch.

Conclusions:

• Solid-solution-mediated lattice matching is a viable strategy for constructing heterostructured molecular crystals.
• This method allows for the formation of complex crystal architectures from incompatible molecular components.
• The resulting heterostructures exhibit the crystal structure of the seed, even with low content of the secondary component.