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Au Atoms Anchored on Amorphous C3N4 for Single-Site Raman Enhancement
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2022-11-23 , DOI: 10.1021/jacs.2c07413
Jian Yu 1 , Chao Chen 2 , Qinghua Zhang 3 , Jie Lin 1 , Xiuyi Yang 1 , Lin Gu 3 , Hui Zhang 4 , Zhi Liu 4 , Yu Wang 5 , Shuo Zhang 5 , Xiaotian Wang 1 , Lin Guo 1
Affiliation  

From spanning bulks to nanoclusters, surface-enhanced Raman scattering (SERS) substrates of noble metals have frequently been explored for a long time. However, further downsizing nanoclusters to the atomic level, the surface plasmon resonance effect disappears, making the research on the SERS effect of atom-scale noble metal still lacking. Here, we discover a single-atom enhanced Raman scattering (SAERS) effect based on Au single atoms anchored on amorphous C3N4 nanosheets (Au1/ACNs). The Au1/ACN exhibits an excellent spectral stability and reproducibility, as the uniform dispersed Au single atoms avoid the agglomeration of Au atoms to generate nonuniformly dispersed “hotspots” that suffer from poor SERS stability and reproducibility. Even only ∼2.5% Au-coated area in the laser illuminated area can yield an enhancement factor of 2.5 × 104. The SAERS effect is attributed to the synergistic effect of Au single atoms anchored on amorphous C3N4, which increases the dipole moment and polarizability of molecules, enhancing the Raman signal of probe molecules. Furthermore, we propose a novel single-atom charge transfer mechanism that single-atom Au dominates higher electron delocalizability and higher electronic density of states near the HOMO level than the Au cluster. Our results will erect a new milepost for the application of single-atom materials in the field of enhanced Raman spectroscopy.

中文翻译:

锚定在无定形 C3N4 上的 Au 原子用于单点拉曼增强

从跨越块体到纳米团簇,贵金属的表面增强拉曼散射 (SERS) 基板经常被探索很长时间。然而,进一步将纳米团簇缩小到原子水平,表面等离子体共振效应消失,使得原子尺度贵金属的SERS效应研究仍然缺乏。在这里,我们发现了基于锚定在非晶 C 3 N 4纳米片 (Au 1 /ACNs)上的 Au 单原子的单原子增强拉曼散射 (SAERS) 效应。金1/ACN 表现出优异的光谱稳定性和重现性,因为均匀分散的 Au 单原子避免了 Au 原子的团聚产生不均匀分散的“热点”,这些“热点”的 SERS 稳定性和重现性差。即使激光照射区域中只有 ∼2.5% 的 Au 涂层区域也能产生 2.5 × 10 4的增强因子。SAERS效应归因于锚定在非晶C 3 N 4上的Au单原子的协同效应,增加了分子的偶极矩和极化率,增强了探针分子的拉曼信号。此外,我们提出了一种新的单原子电荷转移机制,即单原子 Au 在 HOMO 能级附近比 Au 团簇具有更高的电子离域性和更高的电子态密度。我们的成果将为单原子材料在增强拉曼光谱领域的应用树立一个新的里程碑。
更新日期:2022-11-23
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