Rapid synthesis of C-dot@TiO2 core-shell composite labeling agent: Probing of complex fingerprints recovery in fresh water

Abstract

A straightforward and facile one-pot synthesis of carbon dots from pomegranate waste peels was performed using the hydrothermal carbonization technique at a gentle temperature (180 °C). The carbon dots/TiO2 (C-dot@TiO2) core-shell nanostructures (NSs) are prepared by hydrothermal route. The obtained products are well characterized for their chemical composition and morphological features by different spectroscopic and transmission electron microscopy. The synthesized C-dot@TiO2 are characterized by transmission electron microscopy (TEM), fluorescence spectrophotometer, UV−Vis absorption spectra as well as Fourier transform infrared spectroscopy (FTIR). The results reveal that the as-prepared C-dots are spherical shape with an average diameter of 6 μm. Powder dusting method is used to visualize latent fingerprints (LFPs) by staining uncoated and carbon coated NSs on various porous and non-porous surfaces under UV light. The optimized powders are also used to recover latent prints submerged in water on different non-porous dried surfaces including aluminum foil, glass, mica sheet and different textured marbles. Also, the duration of submersion affects the quality of FPs developed; the longer the duration, the worse the quality is. It is clear that core-shell NPs display high sensitivity, reproducibility, selectivity, reliability, and can obtain the complete three levels of friction ridge details.