Ultrasound assisted Eu3+–doped strontium titanate nanophosphors: Labeling agent useful for visualization of latent fingerprints

Abstract

We have established a controllable two–step strategy involving the ultrasound dispersion of the bulk solution to synthesize low–dimensional Eu3+–doped SrTiO3 (1–5 mol%) nanostructures. The crystal structure was carefully inspected by XRD which showed good agreement with a pure cubic phase, also indicating that the dopant's incorporation did not affect the crystalline structure. Photoluminescence emission spectra consists of characteristic red emissions owing to 5D0→7Fj (j= 0,1,2,3,4) transitions of Eu3+ ions. Morphological–behavior indicates that the grains were less agglomerated with a small average particle size of 45 nm. Finally, optimized nanoparticles were further utilized for the visualization of latent fingerprints on smooth surfaces. Visualized latent fingerprint exhibits high sensitivity, high contrast, and can obtain the complete ridge details. The results reveal that well–defined ridge characteristics were visualized under daylight and UV–light, demonstrating the material's efficacy in advanced–forensic investigations and the biometric–process of finger scanning.