Eu-Doped Gd₂MoB₂O₉ Phosphors for Latent Fingerprints Detection

The luminescent powders from rare-earth ions doped oxides have been successfully used for latent fingerprint detection due to high efficiency, high contrast and low background interface. The Gd₂MoB₂O₉:Eu³⁺ phosphors with varying compositions of Eu³⁺ions were synthesized by solid state reaction method. These phosphors were investigated by X-ray diffraction (XRD), diffuse reflectance spectroscopy, photoluminescence (PL), and decay curves studies. Multiphoton relaxation decay rate and coupling strength was evaluated using phonon side band spectrum showing 0.4 mol% doped samples show less non radiative decay rate. The 0.40 mol% of Eu³⁺ ion concentration doped in the Gd₂MoB₂O₉ host lattice show highest photoluminescence emission intensity at 613 nm, in orange red region, monitored at 394 nm excitation. The Gd₂MoB₂O₉:Eu³⁺ phosphors samples were optimized to 900 °C sintering temperature and optimum milling time at 3 min in the present work. The latent fingerprints detection that developed from Gd₂MoB₂O₉:Eu³⁺ phosphors in this work exhibited clearly ridge characteristics under UV illumination. The results revealed thatGd₂MoB₂O₉:Eu³⁺ phosphors are potential practical forensic science applications.