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

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

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.756993

DOI=10.3389/fchem.2021.756993

ISSN=2296-2646

ABSTRACT=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 evidences 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 PL of metal NCs, which elucidates the abnormal PL emission phenomena, including solvent effect, pH-dependent behavior, surface ligand effect, multiple emitter centers, large-Stoke’s shift, etc.