Raman and Photoluminescence Spectroscopic Study of 1-Undecene Functionalized Nanodiamonds

2013 ◽  
Vol 1597 ◽  
Author(s):  
Y. Astuti ◽  
N. R. J. Poolton ◽  
L. Šiller
Keyword(s):  
Optical Properties ◽  
Surface Modification ◽  
Structural Disorder ◽  
Surface Enhanced Raman Spectroscopy ◽  
Peak Position ◽  
Raman Signal ◽  
Chemical Surface ◽  
Chemical Surface Modification ◽  
Surface Enhanced Raman ◽  
Optical Applications

ABSTRACTNanodiamond holds great interest in a variety of optical applications, the properties being correlated with surface modification, and the presence of both impurities and defects (contained either on their surface or within the crystal structure). Undecyl-nanodiamond produced by attachment of 1-undecene onto the nanodiamond surface could be a good candidate as a luminescent marker in the future; therefore, understanding of its optical properties is essential. In this work, the optical properties of the acid-purified nanodiamond and undecyl-nanodiamond were characterised using surface enhanced Raman spectroscopy (SERS) and photoluminescence spectroscopy. The results demonstrate that the characteristic diamond Raman signal at 1330 cm-1 was still observed after chemical surface modification, while the signal at ∼1600 cm-1 (attributed to graphite bands) disappeared after the modification. Broad photoluminescence emission is detected in the range 1.5-2.5 eV (500-800 nm), as typically found for isolated nanodiamond; these emission bands became narrower with attachment of 1-undecene as compared to the sample without surface functionalisation. The observed emission could be related to structural disorder on the nanodiamond surface. The temperature dependence of the intensity, peak position and band widths of each sample has been characterised.

scholarly journals Rapid uropathogen identification using surface enhanced Raman spectroscopy active filters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon D. Dryden ◽  
Salzitsa Anastasova ◽  
Giovanni Satta ◽  
Alex J. Thompson ◽  
Daniel R. Leff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Surface Enhanced Raman Spectroscopy ◽  
Active Filters ◽  
Raman Signal ◽  
Rapid Diagnostics ◽  
Bacterial Classification ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

AbstractUrinary tract infection is one of the most common bacterial infections leading to increased morbidity, mortality and societal costs. Current diagnostics exacerbate this problem due to an inability to provide timely pathogen identification. Surface enhanced Raman spectroscopy (SERS) has the potential to overcome these issues by providing immediate bacterial classification. To date, achieving accurate classification has required technically complicated processes to capture pathogens, which has precluded the integration of SERS into rapid diagnostics. This work demonstrates that gold-coated membrane filters capture and aggregate bacteria, separating them from urine, while also providing Raman signal enhancement. An optimal gold coating thickness of 50 nm was demonstrated, and the diagnostic performance of the SERS-active filters was assessed using phantom urine infection samples at clinically relevant concentrations (105 CFU/ml). Infected and uninfected (control) samples were identified with an accuracy of 91.1%. Amongst infected samples only, classification of three bacteria (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae) was achieved at a rate of 91.6%.

scholarly journals Fabrication-friendly polarization-sensitive plasmonic grating for optimal surface-enhanced Raman spectroscopy

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Arpan Dutta ◽  
Tarmo Nuutinen ◽  
Khairul Alam ◽  
Antti Matikainen ◽  
Peng Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fill Factor ◽  
Surface Enhanced Raman Spectroscopy ◽  
Transverse Magnetic ◽  
Raman Signal ◽  
Optical Resonance ◽  
Excitation Light ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Plasmonic Gratings

Abstract Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance as a dip in its reflectivity with significant near-field enhancement only for transverse-magnetic (TM) polarization of light. We investigated the role of its fill factor, commonly defined as a ratio between the width of the grating groove and the grating period, on the SERS enhancement. We designed multiple gratings having different fill factors using finite-difference time-domain (FDTD) simulations to incorporate different degrees of spectral detunings in their reflection dips from our Raman excitation (488 nm). Our numerical studies suggested that by tuning the spectral position of the optical resonance of the grating, via modifying their fill factor, we could optimize the achievable SERS enhancement. Moreover, by changing the polarization of the excitation light from transverse-magnetic to transverse-electric, we can disable the optical resonance of the gratings resulting in negligible SERS performance. To verify this, we fabricated and optically characterized the modelled gratings and ensured the presence of the desired detunings in their optical responses. Our Raman analysis on riboflavin confirmed that the higher overlap between the grating resonance and the intended Raman excitation yields stronger Raman enhancement only for TM polarized light. Our findings provide insight on the development of fabrication-friendly plasmonic gratings for optimal intensification of the Raman signal with an extra degree of control through the polarization of the excitation light. This feature enables studying Raman signal of exactly the same molecules with and without electromagnetic SERS enhancements, just by changing the polarization of the excitation, and thereby permits detailed studies on the selection rules and the chemical enhancements possibly involved in SERS.

Raman Spectroscopy for the Study of XVI-XVII Centuries Colonial Paintings

2014 ◽  
Vol 1618 ◽  
pp. 141-151 ◽  
Author(s):  
Ma. A. García-Bucio ◽  
E. Casanova-González ◽  
J. L. Ruvalcaba-Sil
Keyword(s):  
Raman Spectroscopy ◽  
San Francisco ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Surface Enhanced Raman Spectroscopy ◽  
Raman Signal ◽  
Invasive Approach ◽  
Full Characterization ◽  
Surface Enhanced Raman ◽  
Historical Objects

ABSTRACTOutstanding information about the material composition and pictorial techniques of the New Spain Colonial painting can be obtained via a full characterization using a set of analytical techniques. Given the cultural importance of this painting, a non-invasive approach is preferred. Moreover, the preparation and use of reference materials using original recipes is necessary for a correct interpretation of the spectroscopic data from historical objects. Here, we present the results obtained via an in-situ Raman spectroscopic analysis of a set of pictorial reference materials, created according to XVI and XVII centuries’ recipes. Several difficulties were encountered, such as the low Raman detection signal, an intrinsic fluorescence of the material, and in some cases even laser-induced degradation. For this reason, the usual molecular Raman analysis was extended to Surface Enhanced Raman Spectroscopy (SERS), which enhances the Raman signal and quenches the fluorescence. It was then applied to the analysis of two wood paintings from the ex-convent San Francisco Tepeyanco, in Tlaxcala.

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