title: A simple model for understanding the fluorescence behavior of Au25 nanoclusters.
abstract: In this work, we synthesized Au25 nanoclusters protected by 2-(naphthalen-2-yl)ethanethiolate. Our experiments revealed that the luminescence of this nanocluster consists of two bands, namely, band I centered at 740 nm and band II centered at 680 nm. Compared with 2-phenylethanethiolate protected Au25 nanoclusters, this new nanocluster has a much higher QY (quantum yield) value (6.5 times higher). Fluorescence lifetime measurements showed multiple components, i.e. 0.15 ns, ∼20 ns and ∼150 ns. With an increase in the electropositivity of the nanocluster, the fluorescence intensity of the nanocluster exhibits a significant enhancement. Since the 2-(naphthalen-2-yl)ethanethiolate protected Au25 nanocluster shares the same Au13/Au12 core-shell structure as the 2-phenylethanethiolate protected nanocluster, the band II fluorescence implies that the surface ligands play a major role in the origin of the fluorescence.
authors.affiliation: Department of Chemistry, Anhui University, Hefei, Anhui 230039, P. R. China. zmz@ahu.edu.cn.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Wang
authors.forename: Xiuyi
authors.initials: X
authors.lastname: Zhu
authors.forename: Tiantian
authors.initials: T
authors.lastname: Cao
authors.forename: Manzhou
authors.initials: M
authors.lastname: Zhu