A porous Au–Ag hybrid nanoparticle array with broadband absorption and high-density hotspots for stable SERS analysis

Li, Kuanguo; Liu, Guangju; Zhang, Sheng; Dai, Yanqiu; Ghafoor, Sonia; Huang, Wanxia; Zu, Zewen; Lu, Yonghua

doi:10.1039/c9nr01744e

Cited by 54 publications

(32 citation statements)

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“…The positions of the characteristic peaks of R6G including 613, 775, 1187, 1309, 1360, 1506, 1569 and 1648 cm −1 could be clearly found in the spectrum, which are in agreement with previous studies. 7,42 The homogeneity of Raman signals is vital to SERS based sensors for a quantitative determination of target analytes. To evaluate the homogeneity of the Raman signal on the 3D hybrid structure, we detect the SERS spectra of R6G molecules with a concentration of 10 −7 M at 50 randomly selected locations within an area of 30 × 30 μm, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The Raman intensity at 1360 cm −1 on the substrates, which is assigned to the aromatic C-C stretching of the R6G molecule, 43 is selected for enhancement factor (EF) estimation. We estimate the sensitivity by using the SERS enhancement factor (EF), which is defined by comparing the intensity of the SERS signal with that of the non-SERS signal: 10,42 are also calculated for the 3D-Ag-HNA substrate at 514 and 633 nm, as plotted in Fig. 5(d).…”

Section: Resultsmentioning

confidence: 99%

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Broadband SERS detection with disordered plasmonic hybrid aggregates

et al. 2020

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Broadband SERS detection with disordered plasmonic hybrid aggregates

et al. 2020

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“…The Raman spectra collected from the flat gold film shows a messy spectrum with fuzzy detectable intensity at 1077 and 1590 cm −1 . The total SERS enhancement factor at CNGAs with G = 1 nm is estimated to be about 6.04 × 10 8 (detail in Figure S4 in the Supporting Information), the Raman spectra of 1 m PATP molecule absorbed on a flat Au film as a reference, which is at the mainstream level in this field.…”

Section: Resultsmentioning

confidence: 99%

Integrated “Hot Spots”: Tunable Sub‐10 nm Crescent Nanogap Arrays

Zhang

Wang

et al. 2019

Advanced Optical Materials

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trapping, [5] single-molecule analysis, [6,7] surface plasmon (SP) enhanced spectroscopy. [6,8,9] To achieve the extremely concentrated and strong electric fields, lots of efforts are contributed to fabricate kinds of plasmonic structures, revealing that sub-10 nm nanogap and nanotip are the two key characteristics. [10,11] In theory, as predicted by Maxwell's equations, the electric fields would become stronger with the decreasing distance between metal nanostructures and can be confined in the gaps; [12][13][14][15][16][17][18][19][20][21] for nanotips, more electrons are distributed at the structural features with high curvature and thus lead to stronger electric fields. [22][23][24][25][26][27][28][29][30] Various plasmonic nanostructures with either nanogaps or nanotips have been fabricated, successfully enhancing the electric fields to several orders of magnitude and confining them in extremely small areas. To obtain better performances, a natural thought is to include both nanogaps and nanotips in one plasmonic nanostructure, i.e., integrated "hot spots." Impressive efforts have been made to develop the multifeature nanostructures. For example, spilt-wedge antenna structures with sub-5 nm gaps, [10] 3D sub-10 nm nanostar dimers gap, [6] and 3D sub-10 nm Ag/SiN x gap with an pair of uniform tips, [31] have been fabricated and highly boosted the local optical field intensity. The fabrication of most these structures has primarily relied on electron beam lithography (EBL) [6,[32][33][34] and focused-ion beam (FIB). [35] These techniques can facilely control the patterns and precisely tune the size and separation, but they suffer from the drawbacks of high-cost, time-consuming, and low-throughput. It is urgently needed to develop a simple and scalable process for their production.Nanoskiving, that combines the deposition of thin metal layers on substrates (flat or structured) and sectioning using a unity of ultramicrotome and diamond knife, would be an alternative fabrication technique for plasmonic nanostructures with both nanogaps and nanotips. [36][37][38][39] Compared with the conventional fabrication techniques (EBL and FIB), nanoskiving is uncomplicated, fast, and scalable, requiring no sophisticated equipment. Nanoskiving has been widely used in fabricating numerous nanostructures, showing the strong capability for nanostructures on-demand. In particular, our research group has reported 3D zig-zag nanowires that possess both nanogaps and nanotips via combining photolithography Plasmonic crescent nanogap arrays (CNGAs) integrated by nanoscale gaps and nanotips exhibit strong capability of light confinement and thus lead to extremely electric field enhancement. The CNGAs with tunable gap-width are fabricated via a low-cost and simple process combining colloidal lithography and nanoskiving techniques. Incident light is captured in the nanogaps and at the two tips of nanocrescent, where extremely strong electric fields are excited. The strong electric fields lead to greatly enhanced surface-enhanced Raman s...

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“…Multiple sensing applications are benefited from the random (but highly dense) arrangement of the plasmon-mediated electromagnetic (EM) hot spots within the structure allowing to obtain the spectrally broadband signal enhancement over the entire visible and near-IR spectral range [11][12][13][14]. Indeed, incorporation of the nanopores into the bulk plasmonic nanostructures with a sub-wavelength overall size provides more intense SERS signal due to multiple hot spots and enlarged surface area increasing probability for analyte molecules to reach these hot spots [15][16][17][18]. Nevertheless, upon excitation with EM radiation, both the arrangement of the nanosized pores and the overall nanostructure geometry govern the resulting response [19,20].…”

Section: Introductionmentioning

confidence: 99%

Laser Printing of Plasmonic Nanosponges

et al. 2020

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Three-dimensional porous nanostructures made of noble metals represent novel class of nanomaterials promising for nonlinear nanooptics and sensors. Such nanostructures are typically fabricated using either reproducible yet time-consuming and costly multi-step lithography protocols or less reproducible chemical synthesis that involve liquid processing with toxic compounds. Here, we combined scalable nanosecond-laser ablation with advanced engineering of the chemical composition of thin substrate-supported Au films to produce nanobumps containing multiple nanopores inside. Most of the nanopores hidden beneath the nanobump surface can be further uncapped using gentle etching of the nanobumps by an Ar-ion beam to form functional 3D plasmonic nanosponges. The nanopores 10–150 nm in diameter were found to appear via laser-induced explosive evaporation/boiling and coalescence of the randomly arranged nucleation sites formed by nitrogen-rich areas of the Au films. Density of the nanopores can be controlled by the amount of the nitrogen in the Au films regulated in the process of their magnetron sputtering assisted with nitrogen-containing discharge gas.

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A porous Au–Ag hybrid nanoparticle array with broadband absorption and high-density hotspots for stable SERS analysis

Abstract: An Au–Ag hybrid nanoparticle array with dense hotspots was constructed through a low-cost route for SERS detection with high sensitivity and stability.

Cited by 54 publications

References 50 publications

Broadband SERS detection with disordered plasmonic hybrid aggregates

Broadband SERS detection with disordered plasmonic hybrid aggregates

Integrated “Hot Spots”: Tunable Sub‐10 nm Crescent Nanogap Arrays

Laser Printing of Plasmonic Nanosponges

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