title: A strategy to achieve efficient dual-mode luminescence in lanthanide-based magnetic hybrid nanostructure and its demonstration for the detection of latent fingerprints.
abstract: We have synthesized a novel inorganic-organic hybrid nanostructure (IOHN) composed of fluoride nanophosphor (NaGd0.78Er0.02Yb0.2F4) and β-diketones complex (Eu(DBM)3Phen). The Le Bail fitting of X-ray diffraction data suggests that the nanophoshor crystallizes in a hexagonal structure (P63/m space group). The TEM studies reveal that the nanophosphor and the IOHN both have average particle size of 6-8nm. The Eu(DBM)3Phen and NaGd0.78Er0.02Yb0.2F4show characteristic down-shifting (DS) and up-conversion (UC) emission, under UV and NIR excitation, respectively. The IOHN comprises an excellent dual-mode optical features (DS and UC) of both the phases. Energy transfer from Er3+(doped in inorganic phase) to Eu3+(coordinated in organic phase) clearly demonstrates for a viable coupling between both the phases. IOHN material was found to be unique for the visualization of latent fingermarks. Because of ultrafine particle size the surface to volume ratio is relatively higher which improves the attachment of particles with the fingermarks. On the other hand, the strong paramagnetic property helps to remove excess material with magnetic wand easily. These properties provide an opportunity to probe even very weak fingermarks. Notwithstanding this, the dual-mode emission is useful for the visualization of latent fingermarks on multi-color surfaces as well.
authors.affiliation: Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Shahi
authors.affiliation: Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Priyam
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Physics, Banaras Hindu University, Varanasi 221005, India. Electronic address: akhilesh_singh343@yahoo.com.
authors.forename: Akhilesh K
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Singh
authors.affiliation: Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Shyam B
authors.initials: SB
authors.lastname: Rai
authors.affiliation: School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Prakash
keywords: Dual-mode luminescence; Energy transfer; Lanthanide complexes; Latent fingerprints; Nanophosphor