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%. A centimeter-scale free-standing 2D heterostructure from molecular crystal and graphene oxide is prepared by a one-step interfacial co-assembly method. The heterostructure exhibits highly sensitive photoresponse and photonic synaptic plasticity for neuromorphic vision application. image