Effect of chain length on the tunneling conductance of gold quantum dots at room temperature

Abstract

Understanding the electronic structure of nanometer-sized metal particles which bridge the gap between the molecules and bulk materials is important due to the fabrication of many nanodevices, like single-electron transistors and molecular switches. Using a simple core-shell model, here, we investigate the variation of electrostatic charging properties of metallic nanoclusters with the chain length of the passivating molecule and cluster core size. The estimation of capacitance (C_c) and charging energy (E_c) as 2Πε₀ε_rR_c/(1+2r/R_c) and e²(1+2r/R_c)/4Πε₀ε_rR_c, respectively, as a function of the core size as well as the intercluster spacing, reveals that longer chains (8 to 10 methylene units) limit the electron transport beyond usefulness.