Decouple the intermolecular interaction by encapsulating an insulating sheath

Abstract

Single-molecule junctions are building blocks for constructing molecular devices. However, intermolecular interactions like winding bring additional interference among the surrounding molecules, which inhibits the intrinsic coherent transport through single-molecule junctions. Here, we employed a nanocavity (dimethoxypillar [5] arene, DMP[5]), which is analogous to electric cables, to confine the conformation of flexible chains (1,8-diaminooctane, DAO) via host-guest interaction. Single-molecule conductance measurements indicate that the conductance of DAO encapsulated with DMP[5] is as high as that of pure DAO, as reproduced by theoretical simulations. Intriguingly, the molecular lengths of the DAO encapsulated with DMP[5] increase from 1.13 nm to 1.46 nm compared with the pure DAO, indicating that DMP[5] keeps DAO upright-standing via the confinement effect. This work provides a new strategy to decouple the intermolecular interaction by employing an insulating sheath, enabling the high-density integration of single-molecule devices.