Field effect and photoconduction in Au25 Nanoclusters Films

TL;DR

This study shows that by selecting specific sizes and ligands, gold nanocluster films can be made to exhibit semiconducting behavior, including field effect and photoconductivity, highlighting their potential in electronic devices.

Contribution

It demonstrates for the first time that Au nanocluster films can be engineered to be semiconducting with field effect and photoconductivity, using controlled size and ligand chemistry.

Findings

Au nanocluster films exhibit semiconducting behavior.

Electrical coupling depends on core size and ligand structure.

Transport mechanism is hopping, similar to organic semiconductors.

Abstract

Quantum confined Au nanoclusters exhibit molecule-like properties, including atomic precision and discrete energy levels. The electrical conductivity of Au nanocluster films can vary by several orders of magnitude, and is determined by the strength of the electronic coupling between the individual nanoclusters in the film. Similar to quantum confined, semiconducting quantum dots, the electrical coupling in films is dependent on the size and structure of the Au core and the length and conjugation of the organic ligands surrounding it. Unlike quantum dots, however, semiconducting transport has not been reported in Au nanocluster films. We demonstrate that through a simple yet careful choice of cluster size and organic ligands, stable Au nanocluster films can electronically couple and become semiconducting, exhibiting electric field effect and photoconductivity. The molecule-like nature of the Au nanoclusters is evidenced by a hopping transport mechanism reminiscent of doped, disordered organic semiconductor films. These results demonstrate the potential of metal nanoclusters as a solution processed material for semiconducting devices.