Synthesis of Photoluminescent Core–Shell-Structured Carbon dots@silica Nanocomposite Fingermark Powders for Latent Fingermarks Visualization

Abstract

To obtain solid-state photoluminescent core–shell-structured carbon dots@silica (C-dots@SiO2) nanocomposites, the C-dots were synthesized by microwave irradiation and were dispersed in SiO2through sol–gel technique. Then, the excellent fluorescent property with excitation-independent feature and the core–shell structure of C-dots@SiO2nanocomposites were successfully characterized through the fluorescence spectroscopy, ultraviolet–visible absorption spectroscopy (UV-Vis), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The as-prepared C-dots@SiO2powder was mixed with reduced iron powder and then applied to latent fingermark detection. The latent fingermarks on several surfaces labeled with C-dots@SiO2fingermark powders emitted blue fluorescence under 365[Formula: see text]nm UV light and exhibited high contrast between the background and the ridges. Additionally, the C-dots@SiO2fingermark powder as a fluorescent label for enhancing latent fingermarks demonstrated greater advantages as compared to the conventional fluorescent fingermark powder especially for latent fingermark deposited on porous surfaces.