Charge Transport through Linear Carbon Atomic Chains

The linear carbon allotrope carbyne has been predicted to display outstanding electrical and mechanical properties, but its preparation and characterisation are hindered by synthetic challenges. Whilst oligoyne and cumul[n]ene models of carbyne have been explored, the end-groups employed to avoid decomposition have a profound effect on their electronic configuration. Here, we show that transmetallation of linear carbon fragments from bulky Au(I) species to Au(0) electrodes delivers stable Au|CCCC…|Au devices. Scanning tunnelling microscope break junction (STMBJ) techniques were used to characterise charge-transport behaviour in these 1D chains (4 − 16 carbon atoms) free of end-capping groups. Shorter chains exhibited oligoyne structures with conductance attenuation as a function of length, while longer chains show evidence of cumulenic equalisation and remarkably enhanced charge-transport. Direct Au|C interfaces grant high conductance and quasi-ballistic transport to 1D carbon chains, providing a pathway to advanced carbon-based nanoelectronics based on the stabilisation of carbyne within the junction environment.

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