Blueshift of plasmon resonance with decreasing cluster size in Au nanoclusters embedded in silica matrix

TL;DR

This study investigates how the plasmon resonance in gold nanoclusters embedded in silica shifts to higher energies as the cluster size decreases, revealing size-dependent optical properties.

Contribution

It demonstrates a size-dependent blueshift of plasmon resonance in Au nanoclusters and suggests a possible interface porosity effect influencing this behavior.

Findings

Plasmon resonance shifts to higher energy with decreasing cluster size.

Blueshift observed in clusters with radii 1.04-1.74 nm.

Interface porosity may influence plasmon behavior.

Abstract

Gold nanoclusters are grown by 1.8 MeV Au++ implantation in silica matrix and subsequent air annealing in the temperature range of 873K-1273K. Post-annealed samples show plasmon resonance in the optical region (~ 2.38-2.51 eV) for average cluster radii ~1.04-1.74 nm. A blueshift of the plasmon peak is observed with decreasing cluster size in the annealed samples. Similar trend of blueshift with decreasing cluster size in case of Au nanoclusters embedded in the porous alumina matrix [B. Palpant, et al., Phys. Rev. B 57, 1963 (1998)] has convinced us to assume a possible role of 'rind' like porosity at the Au nanocluster-matrix interface with available open volume defects in the amorphous silica matrix.