The Effect of Isotropic Pressure on the Electronic Structure and Superatomic Orbitals of Molecular [Ag44(SPhCOOH)30]4-, [Ag44(SPhF2)30]4- & [Ag25(SPhMe2)18]- Nanoclusters

Abstract

We present the first experimental investigation of the effect of increased isotropic pressure on the superatomic electronic structure of metal nanoclusters in the molecular state. Broad multiband absorbing [Ag44(SPhCOOH)30]4-, [Ag44(SPhF2)30]4- & [Ag25(SPhMe2)18]- nanoclusters were optically examined up to 200 MPa, revealing a reversible change to the superatomic electronic structure. Deviations from the ambient spectra became significant above 50 MPa, revealing both red and blue shifts to spectral features. Comparison of the spectral peaks to calculated electronic transitions indicate that electronic states on the ligand are destabilized and that the splitting of the superatomic orbitals decreases with increasing pressure. These findings highlight that under relatively modest pressure the fundamental superatomic electronic structure of metal nanoclusters can be manipulated, thus the optical and electronic properties of functional materials containing nanoclusters such as in solar cells and photocatalytic devices can be tuned by the application of pressure.