Frontiers in Chemistry (Sep 2021)

Physical Origin of Dual-Emission of Au–Ag Bimetallic Nanoclusters

  • Bo Peng,
  • Liu-Xi Zheng,
  • Pan-Yue Wang,
  • Jia-Feng Zhou,
  • Meng Ding,
  • Hao-Di Sun,
  • Bing-Qian Shan,
  • Kun Zhang,
  • Kun Zhang,
  • Kun Zhang

DOI
https://doi.org/10.3389/fchem.2021.756993
Journal volume & issue
Vol. 9

Abstract

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On the origin of photoluminescence of noble metal NCs, there are always hot debates: metal-centered quantum-size confinement effect VS ligand-centered surface state mechanism. Herein, we provided solid evidence that structural water molecules (SWs) confined in the nanocavity formed by surface-protective-ligand packing on the metal NCs are the real luminescent emitters of Au-Ag bimetal NCs. The Ag cation mediated Au-Ag bimetal NCs exhibit the unique pH-dependent dual-emission characteristic with larger Stokes shift up to 200 nm, which could be used as potential ratiometric nanosensors for pH detection. Our results provide a completely new insight on the understanding of the origin of photoluminescence of metal NCs, which elucidates the abnormal PL emission phenomena, including solvent effect, pH-dependent behavior, surface ligand effect, multiple emitter centers, and large-Stoke’s shift.

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