Molecular-Scale Electronics: From Concept to Function

Abstract

Creating functional electrical circuits using individual or ensemble molecules, often termed as "molecular-scale electronics", not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits. Finally, we provide a critical discussion of limitations and main challenges that still exist for the development of molecular electronics. These analyses should be valuable for deeply understanding charge transport through molecular junctions, the device fabrication process, and the roadmap for future practical molecular electronics.

Tuning the Coupling in Single‐Molecule Heterostructures: DNA‐Programmed and Reconfigurable Carbon Nanotube‐Based Nanohybrids

“…The ability to interface individual molecules and nanomoieties to nanoelectronic systems with single‐molecule control is key for the fabrication of next generation molecular (opto)electronic devices 1. In particular, it is of uttermost importance to control both the exact position of active molecules or nanostructures onto nanoelectrodes, and the molecule–electrode separation, as small changes in the organization of the individual nanomoieties forming such nanohybrids can have a major impact on the coupling between the different components 2.…”

Intense redox-driven chiroptical switching with a 580 mV hysteresis actuated through reversible dimerization of an azoniahelicene

“…However, as the current top-down approach is rapidly reaching its physical limits, further miniaturisation will require a transition to the use of single molecules in electronic circuits. 1,2 In particular, the development of molecular switches, part of the 2016 Nobel prize-winning field of molecular machines, 3 will be necessary for the construction of molecular logic gates and memory devices. 4 To function as a memory device, a molecule needs to possess at least two stable forms that can be interconverted upon the application of an external stimulus and be distinguished by a read-out mechanism, usually optical or electrical.…”

“…4 To function as a memory device, a molecule needs to possess at least two stable forms that can be interconverted upon the application of an external stimulus and be distinguished by a read-out mechanism, usually optical or electrical. 1,4 Moreover, the bistability of these forms is important: for redox systems, it can lead to ''read-only'' potentials where both states are stable and not interconverted, thus affording signals that only depend on the redox history of the system, not the applied potential (see Fig. 2).…”

High‐Efficiency Photovoltaic Conversion at Selective Electron Tunneling Heterointerfaces

“…With such matched electronic states, the photoinduced electrons could directly tunnel from LUMO of Z907 molecules to CB of the TiO 2 layer, which is similar to the case of charge transport in single-molecule devices. [25][26][27] On the other hand, the highest occupied molecular orbit (HOMO) of Z907 molecules, lying at ≈ −5.2 eV, just matches the occupied states of SLG, where there is no matched energy band in the TiO 2 layer. For charge densities at −5.2 eV (Figure 1d), they just distribute in the Z907 and SLG layers.…”