Pristine Graphic Carbon Nitride Quantum Dots for the Visualized Detection of Latent Fingerprints

User-friendly fingerprint powders, namely efficient, low-cost and nontoxic ones, are always desirable for the development of latent fingerprints (LFPs). Here, we described the use of pristine graphic carbon nitride quantum dots (g-C3N4 QDs) as a new kind of user-friendly fingerprint powder. The g-C3N4 QDs can be easily prepared from urea and sodium citrate precursors through low temperature solid-phase reaction. Due to their good optical properties and selective interactions with secretion residuals, the g-C3N4 QDs powders were exploited to develop LFPs on different substrates by the powder dusting technique. The LFP images on a plastic bag exhibited a high ridge and furrow contrast ratio, allowing for easy identification of level 1 - 3 details of LFPs. This work indicates that the g-C3N4 QD powders provide good performance for LFP visualization and is likely to be adopted for some applications in forensic investigations.