Fig. 1: Optical properties and PL dynamics of Au₂₄.

a Anatomy of the atomic structure of Au₂₄ determined by single-crystal X-ray diffraction³⁰. Purple = core Au; magenta = surface Au; yellow = S; Carbon tails are omitted for clarity. b UV-Vis absorption (black) and PL (gray) spectra (the asterisk denotes the spectrum “structuration”, which is induced by the solvent). c PL excitation spectra for the two emissions, measured at 650 nm (blue) and 1050 nm (red), respectively. d, e Time-correlated single-photon counting (TCSPC) trajectories of the PL I (detected from 550 to 750 nm) and PL II (detected from 900 to 1000 nm). f Comparison of the TCSPC trajectories of PL I (blue) and PL II (red) in the early 1.5 ns. PL photoluminescence, τ PL lifetime component.