Tunable Electrical Conductivity of Flexible Metal-Organic Frameworks

Abstract

We present the computational design of naphthalene diimide [M(NDIDP), M = Zn, Co, and Fe] judiciously bestowed with both framework flexibility and electrical conductivity. M(NDIDP) MOFs exhibit "wine rack" type flexibility, allowing them to partake in pressure-induced structural transitions at low pressures and room temperature. The MOFs are also equipped with closely packed redox-active NDI moieties, which results in dispersive conduction band minima for efficient charge transport and conductivity. Remarkably, structural transitions of the designed MOFs are found to facilitate the rearrangement of NDI moieties. As a result, charge transport properties of M(NDIDP) MOFs can be finely tuned, which is evidenced by the gradual shift from one-dimensional to twodimensional charge transport and up to 7.5-fold reduction in carrier effective mass (2.76m0-0.37m0) when transitioning between different structural configurations. The unprecedented discovery of flexible MOFs with tunable electrical conductivity arising from configuration-dependent charge transport behavior firmly establishes MOFs as versatile candidate materials for multifunctional electronics.