Control over Molecular Orbital Gating and Marcus Inverted Charge Transport in Molecular Junctions with Conjugated Molecular Wires. (30th November 2022)

• Record Type: Journal Article
• Authors: Nijhuis, Christian A.; Zhang, Ziyu; Adoah, Francis; Nickle, Cameron; Karuppannan, Senthil Kumar; Wang, Lejia; Jiang, Li; Tadich, Anton; Cowie, Bruce; Salim, Teddy; Qi, Dong‐Chen; Thompson, Damien; Barco, Enrique Del
• Is Part Of: Advanced Electronic Materials. Volume 9:Number 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-30
• Subjects: charge transport -- EGaIn, molecular electronics -- Marcus Inverted Region -- selfs‐assembled monolayers; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202200637
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: Recently it is discovered that molecular junctions can be pushed into the Marcus Inverted region of charge transport, but it is unclear which factors are important. This paper shows that the mechanism of charge transport across molecular wires can be switched between the normal and Marcus Inverted regions by fine‐tuning the molecule–electrode coupling strength and the tunneling distance across oligophenylene ethynylene (OPE) wire terminated with ferrocene (Fc) abbreviated as S‐OPEn Fc ( n = 1–3). Coherent tunneling dominates the mechanism of charge transport in junctions with short molecules ( n = 1), but for n = 2 or 3 redox reactions become important. By weakening the molecule—electrode interaction by interrupted conjugation, S‐CH2 ‐OPEn Fc, intramolecular orbital gating can occur pushing the junctions completely into the Marcus Inverted region. These results indicated that weak molecule—electrode coupling is important to push junctions into the Marcus Inverted Region. Abstract : This paper describes how the interplay between the molecule—electrode coupling strength, applied voltage and the tunneling distance (defined by the length of the molecules) can be used to switch between coherent tunneling and incoherent tunneling in Marcus normal and inverted regimes. This ability to control charge transport regimes may improve the energy efficiency of future molecular electronic circuits.