Centrifugation-induced assembly of dense hotspots based SERS substrate for enhanced Raman scattering and quenched fluorescence

Dan Su; Xiao-Yang Zhang; Xia-Yao Chen; Shan-Jiang Wang; Qing-Dian Wan; Tong Zhang

doi:10.1088/1361-6528/ac57d3

Centrifugation-induced assembly of dense hotspots based SERS substrate for enhanced Raman scattering and quenched fluorescence

Nanotechnology. 2022 Mar 17;33(23). doi: 10.1088/1361-6528/ac57d3.

Authors

Dan Su^{1

2}, Xiao-Yang Zhang^{1

3}, Xia-Yao Chen¹, Shan-Jiang Wang¹, Qing-Dian Wan¹, Tong Zhang^{1

2

3}

Affiliations

¹ Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China.
² Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China.
³ Suzhou Key Laboratory of Metal Nano-Optoelectronic Technology, Southeast University Suzhou Campus, Suzhou 215123, People's Republic of China.

PMID: 35196262
DOI: 10.1088/1361-6528/ac57d3

Abstract

Hanging (aggregation stuck to the centrifugal tube) in the centrifugation process is always regarded as an unwanted condition. In this work, we develop a centrifugation-induced assembly of dense hotspots surface-enhanced Raman scattering (SERS) substrates from the hanging phenomenon. We discovered interesting sintering-resistant behavior (maintain the sharp nanotip features) of star-like Au nanoparticles after centrifugation-induced assembly, which is in stark contrast with the sintering phenomenon of sphere-like nanoparticles. We also found that one side of centrifugal-induced Au assemblies is two-dimensional (2D, root mean square (rms) roughness down to ∼10 nm), while the other is three-dimensional (3D, rms roughness more than 100 nm). The close-packed feature of the Au assemblies makes them candidates as dense hotspots based SERS substrates. Through systematic investigation of SERS performance of centrifugation-induced assemblies with different morphology (star-like and sphere-like, 2D and 3D), it was found that the 3D side of star-like Au nanoparticles assembly exhibits the highest SERS enhancement together with quenched fluorescence. The star-like SERS substrate also displays high detection uniformity (with 10^-7M Rhodamine 6G) and a low detection limit (down to 10^-12M Rhodamine 6G).

Keywords: SERS; dense hotspots; plasmonic nanostructure; sintering-resistant.