Rapid visualization of latent fingerprints using novel CaSiO3:Sm3+ nanophosphors fabricated via ultrasound route

Abstract

Latent fingerprints (LFPs) were the most significant identification method for individualization. Most commonly available fingerprints (FPs) in crime spot investigation were latent and patent types. Generally, LFPs were invisible and thus the effective visualization technique necessitates for the analysis of such FPs. In the past years, many traditional visualization techniques have been employed, but suffered with low resolution, sensitivity, contrast and high background noise. To overcome such limitations, we synthesized Sm3+ doped CaSiO3 nanophosphors (NPs) via an ultrasound irradiation route using mimosa pudica (m. p.) leaves extract as a bio-surfactant. The morphological behavior of the prepared samples was extensively studied by varying the concentration of the m. p. extract, ultrasound irradiation duration, pH level of the precursor solution and sonication power. The photoluminescence (PL) emission spectra exhibit characteristic peaks at ∼ 561, 601 and 647 nm, which were attributed to 5G5/2→6HJ (J = 5/2, 7/2 and 9/2) transitions of Sm3+ ions. The Judd-Ofelt (J-O) intensity parameters and other radiative properties were estimated using PL data. The Commission International de I'Eclairage (CIE) color coordinates were positioned in orange-red region shows average correlated color temperature (CCT) value of ∼3576 K. The optimized samples can be used as a labeling agent for the visualization of LFPs on various porous and non-porous surfaces under normal light irradiation. The visualized FPs reveals well defined ridge characteristics, namely whorl, loop, arch, bifurcation, eye, island, bridge, sweat pores, etc. with high sensitivity, selectivity, low contrast and background hindrance. Aforementioned results evidence that the prepared CaSiO3:Sm3+ NPs were promising luminescent materials for solid state lighting and forensic applications.