Journal of Raman Spectroscopy最新文献

{"title":"Waveguide-based Raman enhancement strategies","authors":"Junyi Zhao,&nbsp;Xiumian Cao,&nbsp;Weiqing Xu,&nbsp;Shuping Xu","doi":"10.1002/jrs.6628","DOIUrl":"10.1002/jrs.6628","url":null,"abstract":"<p>Waveguide-enhanced Raman scattering (WERS) is a powerful branch of enhanced Raman technologies that has gained significant progress in recent years because of its advantages, such as reproducibility and robustness. As a complementary tool to surface-enhanced Raman spectroscopy (SERS), WERS provides a powerful solution for reproducible quantification of analytes. According to different Raman enhancement mechanisms, five major WERS implementation strategies, namely, (1) single-mode dielectric waveguide, (2) liquid core waveguide, (3) metal cladding waveguide, (4) resonance mirror waveguide, and (5) double metal cladding waveguide, are classified and described in detail in this review. The flexibility of WERS structures makes them easy to be integrated with 2D devices to obtain a complete on-chip detection scheme, allowing the WERS chip to combine excitation, detection, and data analysis in integrated chips, providing a powerful prospect for real-time and on-site analysis of target samples. This article highlights the principles, implementations, and application scenarios of WERS techniques and evaluates their advantages and limitations, respectively. Finally, the strengths and weaknesses of WERS techniques are summarized, and promising future applications are proposed. This review provides a panoramic view for researchers interested in waveguide-enhanced Raman technology.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"355-376"},"PeriodicalIF":2.5,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of gold nanocones for collocated tip-enhanced Raman spectroscopy and atomic force microscope imaging","authors":"Luke R. McCourt,&nbsp;Ben S. Routley,&nbsp;Michael G. Ruppert,&nbsp;Andrew J. Fleming","doi":"10.1002/jrs.6625","DOIUrl":"10.1002/jrs.6625","url":null,"abstract":"<p>Microcantilever probes for tip-enhanced Raman spectroscopy (TERS) have a grainy metal coating that may exhibit multiple plasmon hotspots near the tip apex, which may compromise spatial resolution and introduce imaging artefacts. It is also possible that the optical hotspot may not occur at the mechanical apex, which introduces an offset between TERS and atomic force microscope maps. In this article, a gold nanocone TERS probe is designed and fabricated for 638 nm excitation. The imaging performance is compared to grainy probes by analysing high-resolution TERS cross-sections of single-walled carbon nanotubes. Compared to the tested conventional TERS probes, the nanocone probe exhibited a narrow spot diameter, comparable optical contrast, artefact-free images, and collocation of TERS and atomic force microscope topographic maps. The 1/\u0000<math>\u0000 <msup>\u0000 <mrow>\u0000 <mi>e</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup></math> spot diameter was 12.5 nm and 19 nm with 638 nm and 785 nm excitation, respectively. These results were acquired using a single gold nanocone probe to experimentally confirm feasibility. Future work will include automating the fabrication process and statistical analysis of many probes.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"336-346"},"PeriodicalIF":2.5,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forensic analysis of white automotive paint of same manufacturer with Raman spectroscopy and chemometrics","authors":"Lei Lei,&nbsp;Geneviève Massonnet","doi":"10.1002/jrs.6626","DOIUrl":"10.1002/jrs.6626","url":null,"abstract":"<p>Discriminating paints of the same color has always been a challenge in automotive paint examination. The process is even more difficult when these paints originate from the same manufacturer and color. Raman spectroscopy is an effective and non-destructive method that is commonly used to differentiate automotive paint. This method is often used to provide a reliable information about pigments and extenders contained in topcoats and is barely used to examine other layers of paints. In this study, A total of 54 white automotive paints from one single manufacturer (Volkswagen) were prepared and analyzed by Raman Spectroscopy. Each layer of the samples was measured in order to evaluate if Raman spectroscopy can provide good discrimination power. Statistical methods were used to characterize and classify these samples. Correlations between paint characteristics and discriminating factors (such as model, topcoat color code, production year, and assembly plant) were also investigated to get a deeper understanding of automotive paints.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 2","pages":"148-160"},"PeriodicalIF":2.5,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Verification of Si wafer first-order phonon peaks for reliable calibration of Raman microscopes","authors":"Nobuyasu Itoh","doi":"10.1002/jrs.6630","DOIUrl":"10.1002/jrs.6630","url":null,"abstract":"<p>Raman microscopes are widely used in various fields and their spectral resolutions differ greatly depending on the system and optical components. Thus, the microscopes must be calibrated before measurement to obtain reliable results. Although the first-order phonon peak of Si wafers at ⁓520 cm⁻¹ is generally used as a calibrant of Raman microscopes, not only is it unclear how the positions of the first-order phonon peaks are comparable over Si wafers of different manufacturers, dopant types and crystal orientations, but they also shift with the temperature and residual stress. We examined the changes in the position of the first-order phonon peak at different temperatures using a HeNe laser at 633 nm and its plasma lines. Because a comparable linear relationship between the temperature and the wavenumber was obtained regardless of the Si wafer examined, most commercially available Si wafers can be used for the calibration of Raman microscopes. Although shifting of the peak was introduced by the laser power due to an increase in temperature at the laser spot, it was less sensitive than broadening of the peak width. A peak shift was observed with a 532-nm laser at 2.1 mW using a 100× air objective lens (numerical aperture: 0.9), but this did not occur with a 633- or 785-nm laser even at more than 10 mW. Thus, less laser power should be used to calibrate Raman microscopes using the first-order phonon peak of Si wafers under high-resolution conditions, especially for a 532-nm laser.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"377-385"},"PeriodicalIF":2.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carrier–phonon interaction and anharmonic phonon decay in ZnS thin film studied by resonance Raman scattering","authors":"Manzar Mushaf Yaqoob,&nbsp;Muhammad Faisal Iqbal,&nbsp;Deliang Wang","doi":"10.1002/jrs.6627","DOIUrl":"10.1002/jrs.6627","url":null,"abstract":"<p>Resonance Raman scattering was carried out on polycrystalline zinc sulfide (ZnS) thin film. The resonance Raman spectra revealed strong carrier–phonon interaction where longitudinal optical phonon (LO) with overtones up to the fourth order and its combination phonons with transverse acoustic (TA) phonons were observed, namely, nLO + mTA (where n and m are integers). The resonance Raman scattering processes were well explained within the framework of the cascade scattering model. The wavenumber of the LO phonon with increased temperature was dominated by anharmonic phonon decay. Detailed experimental data fittings showed that thermal expansion contribution to the nLO phonon overtones differed from the fundamental LO phonon due to the involvement of the scattering of the LO phonons at the Brillion zone edge. The negative value of the mode-Grüneisen parameter for the TA phonon slowed down the wavenumber shift of the combination nLO + mTA phonon modes with increasing temperature compared to the nLO phonons. The anharmonic phonon decay of combination nLO + mTA phonons were dominated by anharmonic phonon decay of nLO phonons.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"347-354"},"PeriodicalIF":2.5,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 20th century and its new colours: Investigating the molecular structures of historical synthetic dyes using Raman spectroscopy","authors":"Alessandro Ciccola,&nbsp;Kathryn Raeburn McClure,&nbsp;Ilaria Serafini,&nbsp;Flaminia Vincenti,&nbsp;Camilla Montesano,&nbsp;Alessandra Gentili,&nbsp;Roberta Curini,&nbsp;Gabriele Favero,&nbsp;Paolo Postorino","doi":"10.1002/jrs.6624","DOIUrl":"10.1002/jrs.6624","url":null,"abstract":"<p>Characterising synthetic dyes on heritage textiles represents a relatively recent research frontier, which aims to obtain new information about the evolution of textile manufacturing and industrial chemistry. Whilst spectral enhancement or amplification methods are often considered a requirement for the Raman analysis of textile dyes, this work highlights the potential of standard Raman spectroscopy for the non-invasive analysis of synthetically dyed fibres. In this research, Raman spectroscopy was used for the chemical characterisation of early 20th century synthetic dyes, in both powder form and on dyed fibres. The dyes were produced by the Italian company Azienda Coloranti Nazionali e Affini (ACNA) and housed in the Sapienza University Museum of Chemistry. The investigation first employed literature research into the ACNA's commercial nomenclature. This information was used to hypothesise likely molecular structures of the dyes, pointing towards the azo dye class. The application of Raman spectroscopy confirmed these hypotheses and the high-quality spectra collected provided structural information about the dye molecules. Spectral features of azo-groups, aromatic moieties, and substituents were observable in spectra. Comparison with a Raman spectrum of wool allowed confident dye signal attribution, and some spectra displayed features linked to changes in the fibre during the dyeing process. Combining literature research and Raman vibrational information proved a powerful non-invasive approach for the characterisation of synthetic dyes, allowing molecular identification of some colorants and structural information for most. Standard Raman spectroscopy may provide a widely applicable, non-invasive method for acquiring information about synthetically dyed historical and artistic textiles in future research.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"324-335"},"PeriodicalIF":2.5,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuously wavelength tunable, continuous wave laser ideal for UV Raman spectroscopy","authors":"Ryan D. Roppel,&nbsp;Sanford A. Asher","doi":"10.1002/jrs.6622","DOIUrl":"10.1002/jrs.6622","url":null,"abstract":"<p>We utilize a novel, high-power, tunable, continuous wave (CW) deep UV laser to measure resonance Raman spectra of phenolate solutions with high signal-to-noise ratios (SNR). In UV resonance Raman (UVRR), increased coupling of the excitation light with a chromophore can transfer molecules into excited states that cause increased heating and photochemistry. Deep UV lasers have traditionally utilized high peak powers to enable efficient single-pass nonlinear conversion from visible into near infrared light. Nonlinear phenomena such as the formation of transient radical species, Raman saturation, thermal heating, and dielectric breakdown can introduce extraneous light sources that can complicate the interpretation of the Raman spectrum. Dielectric breakdown can increase the baseline, increase noise, and sometimes saturate the detector, preventing Raman detection. Spontaneous Raman scattering intensities should scale linearly with the excitation light intensity. However, this linear behavior does not always occur with pulsed laser excitation. This occurs because stimulated Raman scattering can cause a superlinear intensity response, or transient absorption can cause sublinear intensity responses. CW laser excitation excites samples with electric fields that are much lower than typical pulsed laser excitation. This eliminates the nonlinear responses. The geometry of our new CW laser enables high gain in the harmonic generation cavities that achieve high harmonic generation efficiencies. Average power in the deep UV is &gt;30 mW for wavelengths as short as 206 nm. In the work here, we demonstrate that CW excitation is ideal for resonance Raman measurements in general to reduce spectral complexity.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"311-315"},"PeriodicalIF":2.5,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An overview of Principal Components Analysis approaches in Raman studies of cultural heritage materials","authors":"Alessia Coccato,&nbsp;Maria Cristina Caggiani","doi":"10.1002/jrs.6621","DOIUrl":"10.1002/jrs.6621","url":null,"abstract":"<p>The present overview answers the need of assessing the current state of the art concerning the application of principal components analysis (PCA) to Raman spectroscopy investigations of cultural heritage and related materials. An increment of the employment of this multivariate statistic technique to Raman results in the mentioned field began between 15 and 10 years ago, after a very slow start at the turn of the millennium. A delay of about a decade was observed with respect to PCA applied to elemental quantitative data of archaeometric analyses, likely a consequence of the required spectral pre-treatment and to results of complex interpretation. Therefore, it is by now the time to summarize this evolution in a comprehensive, yet very specific way. In this overview, painting constituents were considered, both colouring materials and binders, in addition to natural and synthetic glasses, and biogenic and mineral gemmological materials. A marked unbalance between the studies pertaining to the different sections has been noticed, revealing a concentration of the work mainly on painting materials, including the study of ageing and alteration. The different aims of PCA application to Raman spectra, the various approaches and the achievable results, with the possible arising problems, were underlined, too. Special attention was given to the pre-treatment of the spectra, which was observed to be essential to overcome the influence of several issues concerning bands intensity, spectral noise, background, fluorescence and so on.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 2","pages":"125-147"},"PeriodicalIF":2.5,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6621","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and classification of chill-damaged versus sound kiwifruit using Raman spectroscopy and chemometrics","authors":"Garagoda Arachchige P. Samanali,&nbsp;David J. Burritt,&nbsp;Jeremy N. Burdon,&nbsp;Chelsea Kerr,&nbsp;Sara J. Fraser-Miller,&nbsp;Keith C. Gordon","doi":"10.1002/jrs.6623","DOIUrl":"10.1002/jrs.6623","url":null,"abstract":"<p>The early detection of fruit disorders is crucial to maintaining a consistent, high-quality kiwifruit product. Chilling injury is a physiological disorder found in kiwifruit that can be challenging to identify until it reaches a severe stage or the fruit is cut and opened. Considering this, Raman spectroscopy combined with chemometrics was investigated for sound and chill-damaged ‘Zesy002’ kiwifruit. We carried out spectral analysis on fruit harvested in 2018 and 2019. Damaged and sound fruit samples were separated based on spectral signatures from phenyl propanoids and sugars. Furthermore, the 2018 fruit sample set was used to construct, validate, and test models using support vector machine, principal component analysis–linear discriminant analysis, and partial least squares–discriminant analysis. Additionally, the robustness of the model was assessed using the 2019 fruit sample set considering test set accuracy, sensitivity, and specificity. Support vector machine models were developed and resulted in a 93% accuracy, 85% sensitivity, and 100% specificity to differentiate the test set fruit (2018 season). Principal component analysis–linear discriminant analysis models and partial least squares–discriminant analysis model built with the same data set gave &gt;83% and 93% test accuracy, respectively. Models showed robustness with samples from the 2019 season. This study provides insights into the potential of using Raman spectroscopy for identifying chilling injury in kiwifruit.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 3","pages":"316-323"},"PeriodicalIF":2.5,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134954563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Challenges in surface-enhanced Raman scattering signal for ethephon detection: Theoretical and experimental approaches","authors":"Isabela Bianchi-Carvalho,&nbsp;Cibely S. Martin,&nbsp;Gabriel G. B. Alves,&nbsp;Jaqueline N. Silva,&nbsp;Augusto Batagin-Neto,&nbsp;Carlos J. L. Constantino","doi":"10.1002/jrs.6617","DOIUrl":"10.1002/jrs.6617","url":null,"abstract":"<p>Ethephon, a widely used growth regulator in fruits and vegetables, requires careful monitoring because of its toxicity. However, as far as we know, only two works are found in the literature regarding surface-enhanced Raman scattering (SERS) ethephon detection. Indeed, obtaining the SERS signal revealed to be challenging. Therefore, we have evaluated the SERS signal of ethephon using theoretical (as density functional theory and charge-assisted fragment interaction) and experimental approaches, addressing this limited literature knowledge. Theoretical Raman spectra with Ag or Au atoms at reactive sites exhibited enhanced ethephon SERS signal via Ag<span></span>Cl bonding, consistent with the experimental data. Multiple experimental procedures were employed to obtain the SERS signal, including pH variations, salt addition, excitation laser lines, time dependency, and different SERS substrates (Ag colloid and Ag island films). Salt addition (NaCl) improved SERS signal, correlating with Ag colloid aggregation. Analysis in Ag colloid showed the pH 7.0 as optimal for ethephon detection, using freshly prepared Ag colloid + ethephon dispersion with ethephon powder being directly dissolved into Ag colloid. Only the Ag<span></span>Cl band intensity improved with time. Ag colloid (wet medium — 633 nm laser line) outperformed Ag island films (dry medium — 785 nm laser line).</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 1","pages":"75-85"},"PeriodicalIF":2.5,"publicationDate":"2023-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135036905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}