A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol

TL;DR

This study demonstrates a single-molecule device using two Pd nanocrystals linked by a conjugated dithiol, exhibiting negative differential resistance and Coulomb blockade, with temperature-dependent voltage shifts.

Contribution

It introduces a novel single-molecule switch based on Pd nanocrystals linked by a conjugated dithiol, with detailed tunneling spectroscopy analysis.

Findings

NDR observed at 0.67 V at 300 K

NDR shifts to 1.93 V at 90 K

Coulomb blockade region around ±0.3 V

Abstract

Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, $\sim$5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential resistance (NDR) on a background M-I-M characteristics. The NDR feature occurs at $\sim$0.67 V at 300 K and shifts to a higher bias of 1.93 V at 90 K. When the tip is held in the middle region of the device, a coulomb blockade region is observed ($\pm\sim$0.3 V).