Detection and enhancement of latent fingerprint by powder method using bio-synthesized spherical-shaped Bismuth Oxychloride nanoparticles

Abstract Green fluorescent nanoparticles Bi0.95Tb³⁺0.5Li0.3OCl were successfully synthesized through the solution combustion method using Mimosa pudica as a biofuel. The nanoparticles, annealed at 1000⁰C for three hours, were characterized by X-ray diffraction, revealing a Body Centered Cubic structure. When excited with a 980 nm diode laser, the phosphor emitted a green color. The energy gap of the nanophosphor was estimated to be 3.64eV using diffuse reflectance spectra. High contrast latent fingerprints were developed on porous and semi-porous surfaces by exciting the phosphors with a 980nm diode laser. These fingerprints were compared with a commercially available green luminescent fingerprint. The synthesized nano phosphor proved to be a viable alternative to traditional luminescent powders for forensic applications, offering a simple, fast, highly sensitive, and eco-friendly method for detecting and enhancing fingermarks related to forensic materials.