Fingerprint imaging using N-doped carbon dots

Carbon Dots (CDs) were obtained using a hydrothermal method and used for the detection of fingerprints through fluorescent imaging. Synthesized CDs exhibited a brightness emission at 495 nm, which was related to their structural and chemical properties. The results of detailed surface characterizations by XPS, ss-NMR and fluorescence spectroscopies, suggested that the negative charge of the functionals groups promoted electrostatic interactions between the charged CDs surface functional groups (amine, amide and carboxylic) and the secretion components present in the thin layer of fluid left on the surface upon its direct contact with human fingers. The obtained results were validated by the scientific protocol of the Police Automated Fingerprint Identification System (AFIS) based on a biometric identification.