The π-π stacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/aggregates. However, the exact role of π-to-π channels within typical single crystalline organic semiconductors remains unclear as the orientations of these molecules are diverse, and their control usually requires additional side chain groups that misrepresent the intrinsic properties of the original semiconducting molecules. Therefore, the construction of conduction channels with intrinsic π-π stacking in the molecule-based device is crucial for the utilization of their unique transport characteristics and understanding of the transport mechanism. To this end, we present a molecular intercalation strategy that integrates two-dimensional layered materials with functional organic semiconductor molecules for functional molecule-based electronics. Various organic semiconductor molecules can be effectively intercalated into the van der Waals gaps of semi-metallic TaS₂ with π-π stacking configuration and controlled intercalant content. Our results show that the vertical charge transport in the stacking direction shows a tunneling-dominated mechanism that strongly depends on the molecular structures. Furthermore, we demonstrated a new type of molecule-based vertical transistor in which TaS₂ and π-π stacked organic molecules function as the electrical contact and the active channel, respectively. On/off ratios as high as 447 are achieved under electrostatic modulation in ionic liquid, comparable to the current state-of-the-art molecular transistors. Our study provides an ideal platform for probing intrinsic charge transport across π-π stacked conjugated molecules and also a feasible approach for the construction of high-performance molecule-based electronic devices.

Van der Waals (vdW) integration affords semiconductor heterostructures without constrains of lattice matching and opens up a new realm of functional devices by design. A particularly interesting approach is the electrochemical intercalation of two-dimensional (2D) atomic crystal and formation of superlattices, which can provide scalable production of novel vdW heterostructures. However, this approach has been limited to the use of organic cations with non-functional aliphatic chains, therefore failed to take the advantage of the vast potentials in molecular functionalities (electronic, photonic, magnetic, etc.). Here we report the integration of 2D crystal (MoS₂, WS₂, highly oriented pyrolytic graphite (HOPG), WSe₂ as model systems) with electrochemically inert organic molecules that possess semiconducting characteristics (including perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), pentacene and fullerene), through on-chip electrochemical intercalation. An unprecedented long-range spatial feature of intercalation has been achieved, which allowed facile assembly of a vertical MoS₂-PTCDA-Si junction. The intercalated heterostructure shows significant modulation of the lateral transport, and leads to a molecular tunneling characteristic at the vertical direction. The general intercalation of charge neutral and functional molecules defines a versatile platform of inorganic/organic hybrid vdW heterostructures with significantly extended molecular functional building blocks, holding great promise in future design of nano/quantum devices.