Optical Scattering and Absorption Characteristics of Silver and Silica/Silver Core/shell Nanoparticles.

Bilankohi, Sara Mohammadi

doi:10.13005/ojc/310452

Cited by 19 publications

(12 citation statements)

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“…Reflectance spectroscopy confirmed the presence of AgNPs with a surface plasmon resonance (SPR) at 460 nm (Figure S4a). Whereas microwave-produced AgNPs in colloid are characterized by a narrow SPR band at 406 nm (Figure S4b), surface modes of multiple AgNPs are coupled in aggregates, and the resulting SPR will be red-shifted and broadened when compared with individual nanoparticles. − Using ImageJ software, the calculated surface area of nanoparticles comprised ∼23.4% of the substrate surface area. This level of coverage (∼25%) was also observed by Hasi et al when using a similar approach …”

Section: Resultsmentioning

confidence: 99%

Detection and Quantitation of Trace Fentanyl in Heroin by Surface-Enhanced Raman Spectroscopy

Haddad

Comanescu

Green³

et al. 2018

Anal. Chem.

139

147

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The identification of fentanyl, a main culprit in opioid overdose deaths, has become critical. Whereas Raman spectroscopy is an effective tool for detecting illicit drugs, the weak intensity of Raman scattering can make it difficult to distinguish trace materials. This shortcoming is addressed by surface-enhanced Raman spectroscopy (SERS), which produces strong signal enhancements when target compounds are near metal nanoparticles. This work examines the use of a paper-based substrate impregnated with silver nanoparticles for the detection of trace quantities of fentanyl alone and as an adulterant in heroin. In addition, intensity ratios of diagnostic peaks associated with each substance were fitted to a Langmuir isotherm calibration model and used for the quantitative analysis of fentanyl in heroin mixtures. Linearity was observed at <6% fentanyl, a significant finding that is consistent with concentrations found in drugs seized during law enforcement efforts. In addition, swabbing with these paper-based SERS substrates facilitated the recovery of fentanyl from surfaces, showing this to be applicable for crime scene investigations. However, assessment using the calibration model proved difficult for swabbed samples. Overall, this work demonstrates a potentially simple and sensitive technique for the forensic analysis and quantitation of fentanyl in trace amounts.

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Section: Resultsmentioning

confidence: 99%

Detection and Quantitation of Trace Fentanyl in Heroin by Surface-Enhanced Raman Spectroscopy

Haddad

Comanescu

Green³

et al. 2018

Anal. Chem.

139

147

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“…The location of the LSPR peak of these gold-coated particles depends on their size and surface topology. 44 Figure 4a shows Au-PLLCB nanoparticles with protrusions formed in the suspension that had unbound PLL. In this sample, the gold first forms on the CB surface.…”

Section: Resultsmentioning

confidence: 99%

Carbon Black Templated Gold Nanoparticles for Detection of a Broad Spectrum of Analytes by Surface-Enhanced Raman Scattering

Abbasi

Oliveira

Bothun

et al. 2020

ACS Appl. Nano Mater.

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Surface-enhanced Raman scattering (SERS) is a powerful tool for detection of analytes at low concentrations. Because the electric field generated by surface plasmons decays exponentially with distance, the analyte must be in close proximity to the substrate to generate a measurable Raman signal. This often requires customization of the substrate for a specific subset of molecules. We have produced hybrid carbon−gold nanoparticles for the detection of a broad spectrum of molecules using SERS. Carboxyl-terminated carbon black (CB) nanoparticles were coated with the cationic polyelectrolyte poly(L-lysine) (PLL) and exposed to a tetrachloroauric acid solution. Gold−carbon black (Au-PLLCB) particles were formed by the reduction of gold chloride ions that concentrated on the surfaces of the PLL-coated CB templates. The Au-PLLCB particles produced strong SERS signals for 4-nitrobenzenethiol (4-NBT) in ethanol and for Congo red, crystal violet, and nitrate and sulfate ions in water. The underlying morphology of the carbon black template and the presence of PLL promoted the formation of highly curved gold structures on the surface, yielding hot spots for Raman enhancement. The underlying carbon acted as an absorbent for organic molecules, allowing analytes with poor affinity for the gold surface to concentrate in regions close enough to the particle surfaces to enable detection by SERS. The morphology and chemical nature of the underlying template make the Au-PLLCB particles applicable for SERS-based detection of a wide range of analytes in solution. KEYWORDS: surface-enhanced Raman spectroscopy (SERS), gold−carbon black nanoparticles, SERS-based sensor, analyte detection, nanosensor

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“…Since the radiation absorption by NP as a function of incident radiation wavelength is resonant due to plasmon oscillations, the sintering processes of NP arrays should significantly depend on the wavelength of laser radiation. It was previously established [35,36] that silver NP of spherical shape with an average size of 15 nm effectively absorb radiation with a wavelength 400 nm, and when the wavelength increases, for example, to 527 nm, the absorption efficiency of such particles sharply decreases. However, with the particles enlargement, the resonance wavelength of the absorbed radiation redshifts.…”

Section: Discussionmentioning

confidence: 99%

The Influence of Laser Sintering Modes on the Conductivity and Microstructure of Silver Nanoparticle Arrays Formed by Dry Aerosol Printing

et al. 2019

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The demand for the development of local laser sintering of nanoparticle arrays is explained by the expanding needs for printed electronics for functional microstructure formation, on heat-sensitive substrates in particular. This work is based on the research into the sintering of arrays of silver nanoparticles synthesized in a spark discharge and deposited on a substrate by focused aerosol flow. The sintering was done by continuous and pulsed lasers with wavelengths 527, 980 and 1054 nm. Sintered samples were studied by measuring the resistivity, cross-section profile area and microstructure features. The highest average conductivity, equal to the half of the bulk silver conductivity, was achieved when sintering by continuous radiation with a wavelength 980 nm. The results showed that when using pulsed radiation the direct heating of nanoparticles in the sample surface layer dominates with the formation of a pore-free conductive layer of around 0.5 μm thick and crystallite of 70–80 nm size. It was found that laser sintering by radiation with a wavelength 527 nm required an order of magnitude lower specific energy costs as compared to the longwave laser radiation. The high energy efficiency of laser sintering is explained by special conditions for radiation absorption at plasmon resonance.

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Optical Scattering and Absorption Characteristics of Silver and Silica/Silver Core/shell Nanoparticles.

Cited by 19 publications

References 0 publications

Detection and Quantitation of Trace Fentanyl in Heroin by Surface-Enhanced Raman Spectroscopy

Detection and Quantitation of Trace Fentanyl in Heroin by Surface-Enhanced Raman Spectroscopy

Carbon Black Templated Gold Nanoparticles for Detection of a Broad Spectrum of Analytes by Surface-Enhanced Raman Scattering

The Influence of Laser Sintering Modes on the Conductivity and Microstructure of Silver Nanoparticle Arrays Formed by Dry Aerosol Printing

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