Metal ions have an important impact on the precise control of the synthesis and atomic structural arrangement of noble metal nanoclusters. In this work, the effect of metal ions on the isomer generation of metal nanoclusters is revealed for the first time. Compared with the previous Ag23 nanoclusters with two face-centered cubic (fcc) unit cells twisting 27°, the Ag23 isomer had a higher symmetry structure with two fcc unit cells almost overlapping. In addition, the UV/Vis absorption spectrum of the isomer showed a slight redshift of approximately 14 nm. The redshift might be because of the modulation of electronic structure, which is derived from fine-tuned crystal structure. Based on the experimental results, we provide mechanisms to explain the Cu2+ effect on the structural isomer. This work reports a significant finding to tune precisely the crystal structure and understand the mechanism of shape-controlled synthesis of metal nanoclusters.
Keywords: Ag23 nanoclusters; metal ion effect; optical properties; structural isomers; transformation mechanism.
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