Evolution of CaGd2ZnO5:Eu3+ nanostructures for rapid visualization of latent fingerprints
Nanostructured inorganic materials are potential building blocks for advanced materials and devices with desired functions. Latent fingerprint technology requires cost-effective and high-quality luminescent nanomaterials to identify an individual with sufficient information. We report the synthesis and growth mechanism of novel nanostructured CaGd2ZnO3(CO3)2·H2O and CaGd2ZnO5 materials through a urea- and EDTA-mediated hydrothermal process. The conversion from the carbonate to the oxide form is explained using physicochemical measurements. Furthermore, when doped with Eu3+ ions, CaGd2ZnO5 nanostructures exhibit superior luminescent properties to replace conventional red phosphors for latent fingerprint technology. In contrast to previously reported individual fluorescent nanoparticles, CaGd2ZnO5:5Eu3+ nanostructures provide three levels of identification with high-quality imaging on various hydrophilic and hydrophobic substrates. These properties demonstrate that CaGd2ZnO5:Eu3+ nanorod bundles are a promising luminescent material for solid-state lighting and latent fingerprint technologies.