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On the Non‐Metallicity of 2.2 nm Au 246 (SR) 80 Nanoclusters
Author(s) -
Zhou Meng,
Zeng Chenjie,
Song Yongbo,
Padelford Jonathan W.,
Wang Gangli,
Sfeir Matthew Y.,
Higaki Tatsuya,
Jin Rongchao
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201709095
Subject(s) - nanoclusters , femtosecond , ultrafast laser spectroscopy , materials science , spectroscopy , absorption spectroscopy , absorption (acoustics) , chemical physics , nanoparticle , femtochemistry , plasmon , atom (system on chip) , transition metal , molecular physics , chemistry , nanotechnology , optoelectronics , laser , optics , physics , biochemistry , quantum mechanics , computer science , composite material , embedded system , catalysis
The transition from molecular to plasmonic behaviour in metal nanoparticles with increasing size remains a central question in nanoscience. We report that the giant 246‐gold‐atom nanocluster (2.2 nm in gold core diameter) protected by 80 thiolate ligands is surprisingly non‐metallic based on UV/Vis and femtosecond transient absorption spectroscopy as well as electrochemical measurements. Specifically, the Au 246 nanocluster exhibits multiple excitonic peaks in transient absorption spectra and electron dynamics independent of the pump power, which are in contrast to the behaviour of metallic gold nanoparticles. Moreover, a prominent oscillatory feature with frequency of 0.5 THz can be observed in almost all the probe wavelengths. The phase and amplitude analysis of the oscillation suggests that it arises from the wavepacket motion on the ground state potential energy surface, which also indicates the presence of a small band‐gap and thus non‐metallic or molecular‐like behaviour.