Various visualization of latent fingerprints with Eu3+-activated CaBi2Nb2O9 fluorescent labeling agent

Fingerprints have been effectively used in forensic surveys to identify individuals and provide information. The CaBi2(1,)Nb2O9:2xEu3+ powders were successfully fabricated by a convenient solid-state reaction. The crystal structure, particle morphology, luminescent properties, thermal stability, and ridge-shape details were investigated comprehensively. The X-ray diffraction graphs indicated that the CaBi2(1,0Nb2O9:2xEu3+ phosphors crystallized the orthorhombic phase. Photoluminescence emission spectra displayed an intense peak at 616 nm upon an excitation of 395 nm. The predominant concentration-quenching principle of Eu3+ followed the electric dipole-dipole interaction. The thermal-quenching temperature (T0.5) exceeded 420 K. Internal quantum efficiency (IQE) of the CaBi2Nb2O9:0.20Eu3+ sample reached 71.37%. The right whorl of latent fingerprint (LFP) was also observed clearly on substrates (aluminum foil, glass, and plastic) under a UV of 395 nm and sunlight illumination using optimized CaBi2Nb2O9:0.20Eu3+ samples. These results demonstrate that CaBi2 (1- x)Nb2O9:2xEu3+ phosphors have fingerprint identification application prospects.

Automated summary

This study successfully fabricated CaBi2(1,)Nb2O9:2xEu3+ powders and comprehensively investigated their crystal structure, luminescent properties, and potential applications in fingerprint identification. The results demonstrate the prospects of using these phosphors for fingerprint recognition.