The main goal of this exploratory study was the use of lanthanide-ligand complexes impregnated in silicon dioxide (SiO2) based nanotemplates (doped xerogels) to form stable fluorescent nanocomposites for the purpose of latent fingerprint detection.
This study demonstrates that lanthanide-ligand doped xerogels are useful fingerprint development agents because of their strong and narrow ligand-sensitized fluorescence emission signature of europium metal ions (Eu3+). The use of a narrow bandpass filter at 620 nm suppressed the background emission from the substrate due to the unique narrow emission characteristics of Eu3+. The use of 1,10-phenanthroline (OP) sensitizer in tetraethoxysilane (TEOS) template provided the best fluorescently doped xerogels applicable for latent fingerprint detection on various materials, including metal foil, glass, plastic, colored paper, and a green tree leaf. The fluorescence properties of the doped gels in storage or in labeled fingerprints were stable for months in the research laboratory. Whether or not other doped nanocomposites may further improve the detection of latent fingerprints will be explored in future studies. The descriptions of materials and methods encompasses chemicals; preparation of Eu3+/sensitizer solution; fabrication of Eu3+/sensitizer-doped silicone dioxide-based xerogels; preparation of magnetic Eu3+/sensitizer-doped silicone dioxide-based xerogel powder; development of latent fingerprints by magnetic Eu3+/sensitizer-doped silicone dioxide-based xerogel powder; spectroscopic measurements; and image processing. 8 figures and 15 references