Molecular-Template Vertical Epitaxial Growth of 2D Stacked Organic Cocrystal

2D organic stacked heterostructures (2D OSHs) have become an ideal material for developing on-chip integrated optoelectronic devices due to their unique interlayer coupling effects and interface engineering potentials. However, achieving a controlled synthesis of 2D OSHs remains challenging due to the inherent difficulty of regulating organic molecular orientations and overcoming thermodynamic barriers. Herein, a cocrystal engineering-based template method is reported, where cocrystals are engineered into 2D templates to induce vertical epitaxial growth of other cocrystals, enabling the large-scale synthesis of 2D OSHs. The thickness ratio of two layers can be precisely regulated and exhibits a continuously tunable emission from yellow to blue, where the OSHs with the ratio of 0.25 exhibit near-white emission (CIE: 0.33, 0.35). In addition, the OSHs exhibit excellent dual-band optical waveguide performance. This work provides a new synthesis method for OSH's functional integrated materials in the fields of optical displays and waveguides, promoting their application in the next generation of integrated optoelectronic devices.