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

• CaBi 2 Nb 2 O 9 :Eu3+ phosphors have been synthesized via solid-state reaction firstly. • IQE of the CaBi 2 Nb 2 O 9 :0.20Eu3+ phosphor under an excitation of 395 nm reached 71.37%. • CaBi 2 Nb 2 O 9 :0.20Eu3+ phosphors can be applied in various substrates for LFPs visualization. • The fluorescent LFPs developed with the CaBi 2 Nb 2 O 9 :0.20Eu3+ phosphor has the long-term photostability. Fingerprints have been effectively used in forensic surveys to identify individuals and provide information. The CaBi 2(1− x) Nb 2 O 9 :2 x Eu3+ 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 CaBi 2(1− x) Nb 2 O 9 :2 x Eu3+ 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 (T 0.5) exceeded 420 K. Internal quantum efficiency (IQE) of the CaBi 2 Nb 2 O 9 :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 CaBi 2 Nb 2 O 9 :0.20Eu3+ samples. These results demonstrate that CaBi 2(1− x) Nb 2 O 9 :2 x Eu3+ phosphors have fingerprint identification application prospects. [Display omitted] [ABSTRACT FROM AUTHOR]