Zinc oxide nanoparticles for detection of latent fingermarks on nonporous surfaces

In the present study, zinc oxide (ZnO) nanoparticles were synthesized using hydrothermal method. The prepared nanoparticles were characterized by powder X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, diffused reflectance spectroscopy and Fourier transform infrared spectroscopy. The PXRD confirms the hexagonal phase of the ZnO nanoparticles having space group P63mc and lattice parameters a = b = 3.2498 A, c = 5.2066 A. The obtained ZnO nanoparticles are spherical with an average size of -12.8 nm as confirmed by TEM. XPS analysis confirms Zn to be in the +2 oxidation state. These nanoparticles were used to develop fresh and aged (24 h old) latent fingermarks on dry and moist non-porous surfaces using powder dusting method. These nanoparticles develop sharp and clear fingerprints and second level details of the fingerprints without any background noise can be viewed on glass and aluminum surfaces. The developed nanoparticles are non-hazardous and cost-effective in nature. The proposed powder formulation is a simple to prepare and can be efficiently used to develop latent fingermarks on wide range of dry and wet, smooth, nonporous surfaces recovered from scene of crime.