Graphene Oxide-Assisted Molecular Crystal Co-Assembly for Large-Scale Freestanding 2D Photoresponse Heterostructures with Synaptic Plasticity

2D van der Waals heterostructures (2D vdWHs) have been gaining significant attention in neuromorphic electronics. However, the facile synthesis of large-scale, high-quality freestanding 2D vdWHs remains challenge, particularly for organic counterparts due to susceptible nucleation behaviors and weak intermolecular interactions. Here, the study reports a graphene oxide (GO)-assisted molecular crystal co-assembly method for one-step growth of centimeter-scale freestanding heterostructures. This co-assembly involves the simultaneous assembling of organic and GO precursors at the liquid–liquid interface, where the amphiphilic nature of GO nanosheets facilitates the diffusion of organic molecules and 2D nucleation of organic crystals, and the nanosheets also become enriched to grow a quasi-solid film for the bilayer formation. Owing to integrated photosensitive and charge-trapping properties as well as type II band structure, this heterostructure exhibits exceptional photonic synaptic behaviors, with a paired-pulse facilitation index of 141% and image recognition of 91%.