Speaker
Description
Abstract
Latent fingerprint detection using powder dusting relies on achieving high contrast between the fingerprint details and the underlying surface. Conventional and near-ultraviolet (NUV)-excited powders often suffer from background interference, limiting their effectiveness on multicoloured or fluorescent substrates. Near-infrared (NIR)-to-visible upconversion materials offer a promising alternative by enabling excitation in the NIR region, thereby minimizing background interference and enhancing detection sensitivity. In this study, Ca5Mg4(VO4)6 phosphors co-doped with Yb3+/Er3+ and Yb3+/Ho3+ were synthesized via a solid-state reaction method and investigated as potential upconversion-based fingerprint powders. The phase purity of the phosphors was confirmed by X-ray powder diffraction (XRPD). Under 980 nm excitation, the Yb3+/Er3+ system exhibited strong green emission (~550 nm), while the Yb3+/Ho3+ system showed dominant red emission (~650 nm). Power-dependent and temperature-dependent luminescence measurements were conducted to further evaluate the upconversion behaviour and thermal response of the materials. The distinct and tuneable emissions highlight the potential of these materials for high-contrast latent fingerprint visualization across a range of surfaces, particularly where conventional and UV-based methods are limited, while also expanding the limited understanding of Ca5Mg4(VO4)6 as an upconversion host.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |