We have observed for the first time the surface-enhanced (SE) signal of water in an aqueous dispersion of silver nanoparticles in spontaneous (SERS) and femtosecond stimulated Raman (SE-FSRS) processes with different wavelengths of the Raman pump (515, 715, and 755 nm). By estimating the fraction of water molecules that interact with the metal surface, we have calculated enhancement factors (EF): 4.8 × 10 for SERS and (3.6-3.7) × 10 for SE-FSRS. Furthermore, we have tested the role of simultaneous plasmon resonance and Raman resonance conditions for the a + bν overtone mode of water (755 nm) in SE-FSRS signal amplification. When the wavelength of the Raman pump is within the plasmon resonance of the metal nanoparticles, the Raman resonance has a negligible effect on the EF. However, the Raman resonance with the a + bν mode strongly enhances the signal of the fundamental OH stretching mode of water.
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http://dx.doi.org/10.1021/acs.jpcc.0c06937 | DOI Listing |
Talanta
January 2025
MOE Key Laboratory for Analytical Science of Food Safety and Biology, College of Chemistry, Fuzhou University, Fuzhou, China. Electronic address:
The current surface-enhanced Raman scattering (SERS) substrates typically feature a single energy level, posing challenges in coordinating electromagnetic enhancement (EM) and chemical enhancement (CM), thereby limiting the sensitive detection of numerous crucial target molecules. In this study, novel aggregated nanorings (a-NRs) hybridizing Ag, Au and AgCl are constructed as SERS substrates. On one hand, the obtained a-NRs exhibit robust localized surface plasmon resonance absorption, whose wavelength can be tuned to match three commonly used laser wavelengths (532, 633 and 785 nm) to gain strong EM effect.
View Article and Find Full Text PDFRadiol Imaging Cancer
January 2025
From the Departments of Radiological Sciences (D.H.S.K., I.S., V.M., W.H., K.H.S., D.S.L., S.S.R.), Medicine Statistics Core (T.G.), Pathology (A.S.), and Urology (R.E.R., S.S.R.), David Geffen School of Medicine at UCLA, 885 Tiverton Dr, Los Angeles, CA 90095.
Purpose To determine which quantitative 3-T multiparametric MRI (mpMRI) parameters correlate with and help predict the presence of aggressive large cribriform pattern (LCP) and intraductal carcinoma (IDC) prostate cancer (PCa) at whole-mount histopathology (WMHP). Materials and Methods This retrospective study included 130 patients (mean age ± SD, 62.6 years ± 7.
View Article and Find Full Text PDFNano Lett
January 2025
University of Science & Technology of China, Hefei, Anhui 230026, China.
Metallic oxide can induce localized surface plasmon resonance (LSPR) through creating vacancies, which effectively achieve high carrier concentrations and offer advantages such as versatility and tunability. However, vacancies are typically created by altering the stoichiometric ratio of elements through doping, and it is challenging to achieve LSPR enhancement in the visible spectral range. Here, we have assembled CuO-superlattices to induce a high concentration of oxygen vacancies, resulting in LSPR within the visible spectrum.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Key Laboratory of UV-Emitting Materials and Technology (Northeast Normal University), Ministry of Education, Changchun, 130024, P. R. China.
A novel dual-mode detection method for microRNA-21 was developed. Photoluminescent (PL) and multiphonon resonant Raman scattering (MRRS) techniques were combined by using ZnTe nanoparticles as signal probes for reliable detection. The catalytic hairpin assembly (CHA) strategy was integrated with superparamagnetic FeO nanoparticle clusters (NCs) to enhance sensitivity.
View Article and Find Full Text PDFSci Rep
January 2025
Instituto de Alta Investigación, Universidad de Tarapacá, 1000000, Arica, Chile.
CuZnSn(S,Se) (CZT(S,Se)) thin films exhibit the characteristics necessary to be effective absorbers in solar cells. In this report, the room temperature experimental Raman scattering spectra, recorded at different excitation wavelengths, are systematically analyzed theoretically using the results of DFT harmonic frequencies calculations at the Γ-point for various modifications of kesterite (KS), stannite (ST), and pre-mixed Cu-Au (PMCA) crystal structures. The specific anharmonism-induced features in the spectra of CZT(S,Se) crystals are identified, and the spectral lineshapes at varied strengths of anharmonic interaction are simulated.
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