Influence of the Contact Geometry and Counterions on the Current Flow and Charge Transfer in Polyoxometalate Molecular Junctions: A Density Functional Theory Study

Polyoxometalates (POMs) are promising candidates for molecular electronic applications because (1) they inorganic molecules, which have better CMOS compatibility compared to organic molecules; (2) easily synthesized in a one-pot reaction from metal oxides (MOx) (where the M can be, e.g., W, V, or Mo, and x is an integer between 4 7); (3) POMs self-assemble form various shapes configurations, thus chemical synthesis be tailored specific device performance; (4) redox-active with multiple states that very low voltage switching polarized states. However, deep understanding required if we make commercial devices reality. Simulation modeling most time efficient cost-effective methods evaluate potential performance. Here, use density functional theory combination nonequilibrium Green’s function study transport properties of [W18O54(SO3)2]4–, POM cluster, variety junction configurations. Our calculations reveal profile not only linked structure molecule but also influenced by contact geometry presence ions. More specifically, number bonds electrodes determine current flow. Hence, strong reproducible leads mandatory establish reliable fabrication process. Moreover, although often ignored, our simulations show charge balancing counterions activate conductance channels intrinsic molecule, leading dramatic increase computed at bias. Therefore, role these cannot ignored when based fabricated. In summary, this work shows junctions determined electrode ions around molecule. This significantly impacts such nanoscale devices.