Spectroscopic characterization of Er,Yb:Y2Ti2O7 phosphor for latent fingerprint detection

Er3+ doped, Yb3+ doped, and Er3+/Yb3+ co-doped Y2Ti2O7 phosphors with various concentrations of Er3+ (12–20%), Yb3+ (1-10 at%), and Er3+Yb3+ (1%, and 1,2,3%, respectively) were prepared by solid-state reaction. The phase structure and purity of all prepared phosphors were studied by X-ray diffraction analysis followed by measurement of the hydrodynamic diameter of each sample by Dynamic light scattering. The formation of the pyrochlore structure was confirmed by the observation of relative vibrations by Fourier Transform Infrared Spectroscopy. Moreover, photoluminescence spectra of different co-doped Y2Ti2O7 compounds are presented to check the energy transfer processes of Er3+ and Yb3+ ions. Finally, phosphors were used for the detection of latent fingermarks on various surfaces and a fingerprint minutia extraction algorithm was used for the analysis of extracted minutiae. The analyses confirm that the co-doped phosphors can be useful for the visualization of latent fingerprints once a good detection of their minutiae is obtained.