Latent Fingerprint Imaging Using Dy and Sm Codoped HfO2 Nanophosphors: Structure and Luminescence Properties

Abstract

AbstractThe development of latent fingerprints (LFPs) detected at the site of crime is considered as an imperative physical evidence in forensic investigations. Herein, a rapid and cost‐effective approach using nonhazardous Dy and Sm codoped HfO2 nanophosphors is demonstrated to be utilized for LFP imaging. Sol–gel method can produce Dy and Sm codoped HfO2 of monoclinic phase with crystallite size ranging from ≈10 to 25 nm. While selected area electron diffraction and lattice spacing calculated from high‐resolution transmission electron microscopy confirm monoclinic phase, Le‐Bail profile refinement of X‐ray diffraction (XRD) patterns demonstrate an exponential increase in lattice volume with incorporating various concentrations of Dy and Sm in HfO2 lattice. Exciting Dy and Sm codoped HfO2 with 393 nm photoluminescence spectra show emissions in blue, yellow, and near red regions emerging primarily due to energy transfer from Dy3+ to Sm3+ through multipolar interaction suggested by time resolved decay spectra. Combining excitation and emission spectra, an energy band diagram is proposed. Owing to excellent emissions, Dy and Sm codoped HfO2 are explored for LFP imaging with good selectivity and resolution over multivariate surfaces like float glass and aluminum foil. The third‐level details like enclosure and termination–bifurcation are extracted due to nanosized nature of particles.