Magnetic-plasmonic Ni@Au core-shell nanoparticle arrays and their SERS properties

Lu Wang; Zuobin Wang; Li Li; Jingran Zhang; Jinyun Liu; Jing Hu; Xiaomin Wu; Zhankun Weng; Xueying Chu; Jinhua Li; Zhongliang Qiao

doi:10.1039/c9ra10354f

Magnetic-plasmonic Ni@Au core-shell nanoparticle arrays and their SERS properties

RSC Adv. 2020 Jan 14;10(5):2661-2669. doi: 10.1039/c9ra10354f.

Authors

Lu Wang^{1

2}, Zuobin Wang^{1

2}, Li Li^{1

2}, Jingran Zhang¹, Jinyun Liu³, Jing Hu¹, Xiaomin Wu¹, Zhankun Weng^{1

2}, Xueying Chu⁴, Jinhua Li⁴, Zhongliang Qiao⁵

Affiliations

¹ International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China wangz@cust.edu.cn lil@cust.edu.cn +86 431 85582925 +86 431 85582926.
² Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology Changchun 130022 China.
³ College of Information Engineering, North China University of Science and Technology Tangshan 063210 China.
⁴ School of Science, Changchun University of Science and Technology Changchun 130022 China.
⁵ Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province, School of Physics and Electronic Engineering, Hainan Normal University Haikou 571158 China qzhl2007@hotmail.com +86 898-65861468 +86 898 65861468.

Abstract

In this paper, large-area magnetic-plasmonic Ni@Au core-shell nanoparticle arrays (NPAs) with tunable compositions were successfully fabricated by a direct laser interference ablation (DLIA) incorporated with thermal dewetting method. The magnetic properties of the Ni@Au core-shell NPAs were analyzed and the saturation magnetization (M _s) of the Ni₈₀@Au₂₀ nanoparticles was found to be higher than that of nickel-only nanoparticles with the same diameter. Using Rhodamine 6G (R6G) as a Raman reporter molecule, the surface enhanced Raman scattering (SERS) property of the Ni@Au core-shell NPAs with a grain size distribution of 48 ± 42 nm and a short-distance order of about 200 nm was examined. A SERS enhancement factor of 2.5 × 10⁶ was realized on the Ni₅₀@Au₅₀ NPA substrate, which was 9 times higher than that for Au nanoparticles with the same size distribution. This was due to the enhanced local surface plasmon resonance (LSPR) between the ferromagnetic Ni cores and the surface polariton of the Au shells of each nanoparticle. The fabrication of the Ni@Au core-shell NPAs with different compositions offers a new avenue to tailor the optical and magnetic properties of the nanostructured films for chemical and diagnostic applications.