Origins of Visible and Near-Infrared Emissions in [Au25(SR)18]- Nanoclusters

The origin of photoluminescence in [Au-25(SR)(18)](-) nanoclusters remains elusive, and there is not a universal model that can well explain the experimental result. Here, we design Au-25 nanoclusters protected by four different types of ligands for investigation of the photoluminescence mechanism by looking into the visible to near-infrared emissions. On the basis of time-resolved emission and nanosecond transient absorption spectroscopy analyses, we propose a model that can well explain the emission bands of Au-25 nanoclusters. The visible and near-infrared emissions have different lifetimes and are found to arise from the core-shell charge transfer state and the Au-13 core state, respectively. The obtained insight will help to understand how the excited state deactivates and to further engineer the photoluminescence of metal nanoclusters.

Automated summary

A model that can explain the emission bands of Au-25 nanoclusters was proposed based on time-resolved emission and nanosecond transient absorption spectroscopy analyses. The visible and near-infrared emissions were found to arise from the core-shell charge transfer state and the Au-13 core state, respectively. This insight will aid in understanding how the excited state deactivates and in further engineering the photoluminescence of metal nanoclusters.