Bianthrone in a Single-Molecule Junction: Conductance Switching with a Bistable Molecule Facilitated by Image Charge Effects

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• 作者：Samuel Lara-Avila ; Andrey Danilov ; Victor Geskin ; Sad Bouzakraoui ; Sergey Kubatkin ; Jrme Cornil ; Thomas Bj&#248 ; rnholm
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：December 9, 2010
• 年：2010
• 卷：114
• 期：48
• 页码：20686-20695
• 全文大小：468K
• 年卷期：v.114,no.48(December 9, 2010)
• ISSN：1932-7455

文摘

Bianthrone is a sterically hindered compound that exists in the form of two nonplanar isomers. Our experimental study of single-molecule junctions with bianthrone reveals persistent switching of electric conductance at low temperatures, which can be reasonably associated with molecular isomerization events. Temperature dependence of the switching rate allows for an estimate of the activation energy of the process, on the order of 120 ± 50 meV. Quantum-chemical calculations of the potential energy relief of neutral bianthrone and its anion, including identification of transition states, yields the isolated molecule isomerization barriers too high vs the previous estimate, though compatible with previous experimental studies in solution. Nevertheless, we show that the attraction of the anion in the vicinity of the metal surface by its image charge can change the energetic landscape, in particular, by significantly reducing the barrier to values compatible with the observed switching behavior.