Interplay of kernel shape and surface structure for NIR luminescence in atomically precise gold nanorods.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39174541.
- Also identified by DOI 10.1038/s41467-024-51642-w and PMC identifier 11341786.
- Licence recorded as CC BY-NC-ND.
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Abstract
It is challenging to attain strong near-infrared (NIR) emissive gold nanoclusters. Here we show a rod-shaped cluster with the composition of [Au<sub>28</sub>(p-MBT)<sub>14</sub>(Hdppa)<sub>3</sub>](SO<sub>3</sub>CF<sub>3</sub>)<sub>2</sub> (1 for short, Hdppa is N,N-bis(diphenylphosphino)amine, p-MBT is 4-methylbenzenethiolate) has been synthesized. Single crystal X-ray structural analysis reveals that it has a rod-like face-centered cubic (fcc) Au<sub>22</sub> kernel built from two interpenetrating bicapped cuboctahedral Au<sub>15</sub> units. 1 features NIR luminescence with an emission maximum at 920 nm, and the photoluminescence quantum yield (PLQY) is 12%, which is 30-fold of [Au<sub>21</sub>(m-MBT)<sub>12</sub>(Hdppa)<sub>2</sub>]SO<sub>3</sub>CF<sub>3</sub> (2, m-MBT is 3-methylbenzenethiolate) with a similar composition and 60-fold of Au<sub>30</sub>S(S‑t‑Bu)<sub>18</sub> with a similar structure. time-dependent DFT(TDDFT)calculations reveal that the luminescence of 1 is associated with the Au<sub>22</sub> kernel. The small Stokes shift of 1 indicates that it has a very small excited state structural distortion, leading to high radiative decay rate (k<sub>r</sub>) probability. The emission of cluster 1 is a mixture of phosphorescence and thermally activated delayed fluorescence(TADF), and the enhancement of the NIR emission is mainly due to the promotion of k<sub>r</sub> rather than the inhibition of k<sub>nr</sub>. This work demonstrates that the metal kernel and the surface structure are both very important for cluster-based NIR luminescence materials.