A molecular design principle towards luminescent polymorphic organic heterostructured architectures

Abstract

Polymorph-selective synthesis of organic heterostructured architectures represents a tough challenge due to the diversity of organic species and the growth complexity of seed crystals with specific polymorphs as well as complicated epitaxial relationships among diverse constituent materials. Herein, we employ three polymorphic π-conjugated molecules to construct three types of binary organic heterostructures based on a molecular design principle via a solution seeded-mediated strategy, where pre-existing crystals with a specific polymorph serve as seeds to afford epitaxial growth of another organic crystal. As a consequence, the crystal form of the second growth component can be exclusively determined regardless of the synthetic procedures. Indeed, epitaxial growth of these dual-color-emitting organic heterostructures was realized depending on the small lattice mismatch between two specific polymorphs of any two constituent materials, which is determined by their structural compatibility and elaborate selection of the seed crystals. The present work offers a promising platform to understand polymorph-selective synthesis of organic heterostructured microstructures, which may be used to achieve unprecedented photonic and electronic properties.