Magnetic perovskite nanoparticles for latent fingerprint detection

Fingerprints form when fingers touch a solid surfaceand are considered the best way for individual identification. However, the current latent fingerprint (LFP) developing methods cannot meet the demand for high sensitivity and being convenient and healthy. Herein, bifunctional Fe 3 O 4 @SiO 2 -CsPbBr 3 powders have been designed and fabricated and exhibit good magnetic and strong fluorescent properties. The magnetism of Fe 3 O 4 can avoid dust flying, while the fluorescence of CsPbBr 3 ensures the high definition of LFPs. Clear fingerprints have been detected on various solid substrates using the Fe 3 O 4 @SiO 2 -CsPbBr 3 powders instead of eikonogen. Detailed characterization studies suggest that the ammonium cationic groups on the surface of nanoparticles (NPs) have strong adhesive interactions with the residues of fingerprints because of the electrostatic attraction between them. Therefore, the convenient operation and excellent resolution offer great opportunity in the practical application of fingerprint detection and other areas. Fe 3 O 4 @SiO 2 -CsPbBr 3 as a new type of bifunctional magnetic-fluorescent nanoparticle has been designed to detect latent fingerprints and showed excellent performance in detecting fingerprints.