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Powders and films composed of tin dioxide (SnO2) are promising candidates for a variety of high-impact applications, and despite the material’s prevalence in such studies, it remains of high importance that commercially available materials meet the quality demands of the industries that these materials would most benefit. Imaging techniques, such as scanning electron microscopy (SEM), atomic force microscopy (AFM), were used in conjunction with Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) to assess the quality of a variety of samples, such as powder and thin film on quartz with thicknesses of 41 nm, 78 nm, 97 nm, 373 nm, and 908 nm. In this study, the dependencies of the corresponding Raman, XPS, and SEM analysis results on properties of the samples, like the thickness and form (powder versus film) are determined. The outcomes achieved can be regarded as a guide for performing quality checks of such products, and as reference to evaluate commercially available samples.
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Chemical composition effect on latent print development using black fingerprint powders
Fingerprint development has been used to visualize latent prints since the 19th century, and several companies produce a variety of commercially available black fingerprint powders. While the method to develop fingerprints has been refined over the years, the composition of fingerprint powders that are used in print development has not been studied extensively. Six different black fingerprint powders were studied using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS) and zeta potential, attenuated total reflectance infrared spectroscopy (ATR-IR), Raman spectroscopy, powder X-ray diffraction (PXRD), and solution-phase nuclear magnetic resonance spectroscopy (NMR) in addition to a quality study involving certified latent print examiners. When comparing all chemical, physical, and morphological results for the fingerprint powder, this study determined that powders ranked best by latent print examiners are fingerprint powders that mainly contain carbon and oxygen with particle sizes around 50 nm and spherical morphology. Powders with large particle sizes, irregular shape, and elemental compositions consisting of many elements ranked poorly in the quality study performed.
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- Award ID(s):
- 1828358
- PAR ID:
- 10298807
- Date Published:
- Journal Name:
- Forensic chemistry
- Volume:
- 26
- ISSN:
- 2468-1709
- Page Range / eLocation ID:
- 100366
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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