Raman spectroscopy of nanostructures and nanosized materials

Abstract

The interest in micro and tip-enhanced Raman spectroscopy in analyzing nanosized and nanostructured materials, chiefly semiconductors, oxides and pristine or functionalized carbon nanotubes, is reviewed in the light of contributions to this Special Issue. Particular attention is paid to the fact that chemical reactions, size or shape distribution, defects, strain and couplings may add to nanodimensionality in defining the Raman signature.

The role of brookite in mechanical activation of anatase-to-rutile transformation of nanocrystalline TiO2: An XRD and Raman spectroscopy investigation

“…15 As a complementary tool, Raman spectroscopy has already proven to be a reliable method to characterize the small variations in the microstructural characteristics of nc-materials. 16 Raman spectroscopy can provide phase identification and, possibly, size estimation. 16 Correct interpretation of the Raman spectra of nc-TiO 2 powders enables the estimation of various characteristics, such as the existence of mixed phases (anatase in combination with considerable amount of rutile or brookite phase), crystallite size and crystallite size distribution, discrepancy from stoichiometry as well as the type of any stoichiometric defects.…”

“…16 Raman spectroscopy can provide phase identification and, possibly, size estimation. 16 Correct interpretation of the Raman spectra of nc-TiO 2 powders enables the estimation of various characteristics, such as the existence of mixed phases (anatase in combination with considerable amount of rutile or brookite phase), crystallite size and crystallite size distribution, discrepancy from stoichiometry as well as the type of any stoichiometric defects. 6,12 This paper addresses a study of the mechanical activation of polymorphic phase transformation in nc-TiO 2 powder by a combination of X-ray diffraction and Raman spectroscopy methods.…”

Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques

“…Raman spectroscopy measures the inelastic scattering of a light source by a compound that occurs as a result of lowenergy, symmetrical vibrational and rotational modes of the compound, and can be performed on aqueous samples as an alternative to FT-IR. 42,43 In contrast with electron microscopy, Raman spectroscopy relies on light and is not limited by the environmental conditions of an electron beam. This technique is typically used to analyze small-molecule moieties, but at the nanoscale, phonons induced by the incident optical field are confined by the spatial dimensions of the particle being analyzed, yielding unique Raman spectra for nanomaterials attributed to their size, allowing this technique to be applied for both molecular characterization and …”

“…42,44,45 Raman spectroscopy, in combination with microscopy, can prove particularly useful for characterization of nanomaterials that have heterogeneous surfaces. [46][47][48][49][50] WITec, a German company, has recently launched the first commercially available SEM-Raman instrument.…”

“…8,42 In addition, optical phonon confinement in Raman spectroscopy can reveal the physical features of nanomaterials during the manufacturing process. 44 In this way, this instrument can help the applicant monitor the chemical reactivity of the drug or DDS along the synthesis process.…”