Molecular diodes with rectification ratios exceeding 105 driven by electrostatic interactions

Abstract

Molecular diodes operating in the tunnelling regime are intrinsically limited to a maximum rectification ratio R of ∼10. To enhance this rectification ratio to values comparable to those of conventional diodes (R ≥ 10) an alternative mechanism of rectification is therefore required. Here, we report a molecular diode with R = 6.3 × 10 based on self-assembled monolayers with Fc-C≡C-Fc (Fc, ferrocenyl) termini. The number of molecules (n(V)) involved in the charge transport changes with the polarity of the applied bias. More specifically, n(V) increases at forward bias because of an attractive electrostatic force between the positively charged Fc units and the negatively charged top electrode, but remains constant at reverse bias when the Fc units are neutral and interact weakly with the positively charged electrode. We successfully model this mechanism using molecular dynamics calculations.

The Drive Force of Electrical Breakdown of Large‐Area Molecular Tunnel Junctions

“…[26e,38] Therefore, the changes in the SAM‐bottom electrode resistance is overshadowed by the large SAM//top electrode resistance in our junctions leaving J 0 independent of M. Note, the values of J and J 0 reported here are determined using the geometric contact area of the junctions, but the effective contact area is ≈10 6 times smaller than the geometrical contact area (see ref. for details and ref. [36b] for more discussions).…”

Tunable rectification in a molecular heterojunction with two-dimensional semiconductors

“…T he ultimate objectives in the field of molecular electronics are to realize electronic functionalities, such as rectifying, optical switching, and thermoelectric effects, at the device miniaturization limit and to systemize all the aspects of the charge transport mechanisms for rational device design [1][2][3][4][5][6][7][8][9][10][11][12] . Specially designed molecular species have been utilized for the realization of specific (or desired) device functions.…”

“…This asymmetric energy alignment in the junction can cause the different sequential tunneling through the acceptor and donor depending on the polarity of the applied voltage, which could yield the rectification property of the molecular junction. In the case of the ferrocenyl molecules that composed of long alkyl chain and ferrocenyl termini unit, they can also exhibit the rectification characteristic because the charge transport pathways are mainly determined by the relative HOMO level of the ferrocenyl unit according to voltage polarities 11,12 . In this sense, specially designed molecular species that can differently engineer the band alignment of the molecular units according to the voltage polarity is dispensable for implementing a desirable diode's behavior in molecular electronic junction.…”

Simultaneous implementation of resistive switching and rectifying effects in a metal-organic framework with switched hydrogen bond pathway

“…(ii) The switched hydrogen bond pathway can impart the proton channels with voltage-gated effect and then increase the ON/OFF ratio of the devices. (iii) Asymmetric structure that originated from the chiral proton channel can endow the device with rectifying effect, as in the cases of the molecular rectifiers (43). Moreover, high-density storage is another important performance pursued by the semiconductor industry, and the characteristics of the long-range order of MOFs in microcosmic may provide a possibility for high-density storage.…”