Potential of Sr₄Al₁₄O₂₅: Eu ²⁺,Dy³⁺ inorganic oxide-based nanophosphor in Latent fingermark detection

In this paper, the potential of the Sr₄Al₁₄O ₂₅: Eu²⁺,Dy³⁺ fluorescent nanophosphor is explored to visualize the latent fingermarks. The nanophosphor has been synthesized using self-propagating high temperature synthesis and shows intense luminescence and strong long after glow properties. These nano particles have been characterized for their particle size, crystalline phase, and photoluminescent properties. The calculated PL CIE coordinates (0.138, 0.359) correspond to the blue-green shade. Different porous, non-porous, as well as slightly non-smooth surfaces are taken and successfully tested for latent fingerprints development with the prepared Sr₄Al₁₄O ₂₅: Eu²⁺,Dy³⁺ fluorescent nanophosphor powder. Present nano powder is advantageous to use on luminescent or multicolored surfaces as it gives greater contrast and also eliminates the problem of background interferences with the friction ridges due to its strong long after glow property. The results are very good when latent fingerprints were developed on the currency notes with optical variable ink and highly fluorescent pattern areas.