Organic molecular crystals with controllable bending angles are crucial interconnectors in integrated optoelectronic chips, which can precisely guide optical signals along a predetermined path to achieve effective optical path steering. Nevertheless, current methods of tailoring molecular crystals with desired bent geometric features yet without fractured bending interface has not yet been fully realized. Here, we addresses this issue by proposing a universal "molecular cocrystal" strategy that introduces directional charge-transfer non-covalent interactions into molecular systems to weaken the original interactions, thereby triggering the spontaneous deformation transition from crystal slippage to bending. Significantly, a diverse range of self-assembled bent crystals with accurate angles ranging from 61.8° to 85.0° have been synthesized without destroying the structural integrity of the crystals. The proposed strategy is also applied to construct hierarchical bent microstructures with 2 to 6 bends. These as-prepared bent crystals exhibit excitation position-dependent anisotropic optical behaviors, which are applied into the photonics switch with adjustable on/off ratio. This methodology offers a versatile pathway to purposely design bent crystals with tailored angles, thereby laying a structural foundation for the on-chip organic optoelectronics.
Ma et al. (Thu,) studied this question.