Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Abstract

We report the synthesis of spherical-shaped rare-earth (Eu3+ and Tb3+) ions doped CaMoO4 nanoparticles in double solvents (IPA and H2O) with the help of autoclave. The X-ray diffraction patterns well match with the standard values and confirm the crystallization in a tetragonal phase with an I41/a (88) space group. The luminescence spectra exhibit the strong red and green emissions from Eu3+ and Tb3+ ions doped samples, respectively. The X-ray photoelectron spectroscopy results show the oxidation states of all the elements present in the sample. The temperature-dependent luminescence spectra reveal the stability of Eu3+ and Tb3+ ions doped samples. The red- and green-emitting Eu3+ and Tb3+ ions doped CaMoO4 samples were used for detection and enhancement of latent fingerprints which are the common evidences found at crime scenes. The enhanced latent fingerprints obtained on different surfaces have high contrast with low background interference. The minute details of the fingerprint which are useful for individualization are clearly observed with the help of these nanopowders.

Interpol review of fingermarks and other body impressions 2016–2019

“…For ethical and health and safety reasons, this practice should be avoided at all costs. Similarly to the 2013–2016 report, we have taken the decision to cite these publications without describing their content further [ [257] , [258] , [259] , [260] , [261] , [262] , [263] , [264] , [265] , [266] , [267] , [268] , [269] , [270] , [271] , [272] , [273] , [274] , [275] , [276] , [277] , [278] , [279] , [280] , [281] , [282] , [283] , [284] , [285] , [286] , [287] , [288] , [289] , [290] , [291] , [292] , [293] , [294] , [295] , [296] , [297] , [298] , [299] , [300] , [301] , [302] , [303] , [304] , [305] , [306] , [307] , [308] , [309] , [310] , [311] ,…”

In-vivo evaluation of molybdenum as bioabsorbable stent candidate

“…The chemistry of Mo in its higher oxidation states is dominated by molybdate compounds (such a as calcium molybdate (such as CaMoO 4 , MgMoO 4 and/or Na 2 MoO 4 ) [ [49] , [50] , [51] ]. The strong absorption bands situated at 750-875 cm −1 are originated from the antisymmetric stretching vibrations in the tetrahedral MoO 4 2- [ 50 , 52 ]. The splitting of the Mo O stretching at 993 and 1028 cm −1 reflects the good crystallinity of the protective films.…”

Nanoparticles used for fingermark detection—A comprehensive review

“…Seeta Rama Raju et al synthesized CaCd 2 ZnO 5 :Eu of width 550 nm and length 1.8 μm in size and observed good ridge detail without background staining on various substrates (Seeta Rama Raju et al, ). Bharat et al used 300 to 500 nm‐sized red and green emitting CaMoO 4 :Eu and CaMoO 4 :Tb UCNPs (Bharat, Raju, & Yu, ). Detecting aged fingermarks with CaMoO 4 :Eu was substrate dependent but CaMoO 4 :Tb gave consistently good ridge detail irrespective of the substrate.…”