Charge transport through molecular ensembles: Recent progress in molecular electronics

This review focuses on molecular ensemble junctions in which the individual molecules of a monolayer each span two electrodes. geometry favors quantum mechanical tunneling as dominant mechanism charge transport, translates perturbances scale bond lengths into nonlinear electrical responses. The ability to affect these responses at low voltages and with variety inputs, such de/protonation, photon absorption, isomerization, oxidation/reduction, etc., creates possibility fabricate molecule-scale electronic devices that augment; extend; and, some cases, outperform conventional semiconductor-based electronics. Moreover, devices, part, themselves by defining single-nanometer features atomic precision via self-assembly. Although share many properties single-molecule junctions, they also possess unique present different set problems exhibit properties. primary trade-off is complexity for functionality; disordered ensembles are significantly more difficult model, particularly atomistically, but static can be incorporated integrated circuits. Progress toward useful functionality has accelerated recent years, concomitant deeper scientific insight mediation transport experimental platforms enable empirical studies control defects artifacts. separates trade-offs, complexity, sensitivity their constituents; bottom electrode anchored nature anchoring chemistry both chemically respect coupling; layer relationship among structure, output; top realizes an junction its second molecule–electrode interface. Due growing interest accessibility this interdisciplinary field, there now sufficient parts able treat them separately. When viewed way, clear structure–function relationships emerge serve design rules extracting functionality.