Bistable Interface: Reversible Switching of Rectifying to Nonrectifying Current Across Heterostructured Thin Films of MOFs

A diverse range of physicochemical properties offered by metal-organic frameworks (MOFs) is highly engaging in thin film configurations, specifically for device applications. Heterostructured thin films of MOFs allow to utilize the unique interfaces that develop within such configurations. Typically, interface is monostable and electrical transport across heterostructured MOF thin films has so far been realized to be either Ohmic or rectifying (p-n junction) type. This work reports the emergence of a bistable interface in a heterostructured thin film of Mott-like electrically insulating MOFs whereby rectifying to nonrectifying current can be reversibly switched by applying thermal energy. The inherent resistive switching behavior of both the individual MOF layers at different temperatures coupled with charge-transfer apparently makes the interface complex. This work presents the fabrication of a lattice-mismatched MOF-on-MOF heterostructured thin film, consisting of two Mott-like insulators, Cu(Cys)2 and Cu-TCNQ. Electrical transport measurements across this well-defined interface unveil bifunctionalities of both p-n junction diodes and memory storage devices within a single design architecture.image