Application of core-shell-structured CdTe@SiO _2 quantum dots synthesized via a facile solution method for improving latent fingerprint detection

摘要

Fingerprint detection is important in criminal investigation. This paper reports a facile powder brushing technique for improving latent fingerprint detection using core-shell-structured CdTe@SiO _2 quantum dots (QDs) as fluorescent labeling marks. Core-shell-structured CdTe@SiO _2 QDs are prepared via a simple solution-based approach using NH _2NH _2 H _2O as pH adjustor and stabilizer, and their application for improving latent fingerprint detection is explored. The obtained CdTe@SiO _2 QDs show spherical shapes with well-defined core-shell structures encapsulating different amounts of QDs depending on the type of the pH adjustor and stabilizer. Moreover, the fluorescence of CdTe@SiO _2 QDs is largely enhanced by surface modification of the SiO _2 shell. The CdTe@SiO _2 QDs overcome the oxidation problem of pure CdTe QDs in air, thus affording better variability with strong adhesive ability, better resolution, and bright emission colors for practical application in latent fingerprint detection. In comparison with the conventional fluorescence powders, silver powders, and others, the effectiveness of CdTe@SiO _2 QD powders for detection of latent fingerprints present on a large variety of object surfaces is greatly improved. The synthesismethod for CdTe@SiO _2 QDsis simple, cheap, and easy for large-scale production, and thus offers many advantages in the practical application of fingerprint detection.