title: Effect of surface coating on optical properties of Eu(3+)-doped CaMoO4 nanoparticles.
abstract: A simple polyol method has been used for the synthesis of CaMoO4:Eu (core), CaMoO4:Eu@CaMoO4 (core/shell) and their silica coated CaMoO4:Eu@CaMoO4 (core/shell/shell) nanoparticles. X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Fourier transform Raman (FT-Raman), Fourier transform infrared (FT-IR), UV/Vis absorption and photoluminescence (PL) spectroscopies techniques has been employed for their characterization. XRD patterns and FT-Raman spectra showed that these nanoparticles have a scheelite-type tetragonal structure without the presence of deleterious phases. These nanoparticles were easily dispersed in water, producing a transparent colloidal solution. The optical energy band-gap decreases after core/shell formation due to increase the crystalline size. The photoluminescence (PL) spectra of the as-synthesized core, core/shell and core/shell/shell nanoparticles measured with an excitation source wavelength of 325nm showed that the emission intensity was increases after shell formation around the surface of core nanoparticles.
authors.affiliation: King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. Electronic address: aneesaansari@gmail.com.
authors.forename: Anees A
authors.initials: AA
authors.lastname: Ansari
authors.affiliation: Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Parchur
authors.affiliation: Research Center, College of Science, King Saud University, P.O. Box 2455, Riyadh, Saudi Arabia.
authors.forename: Manawwer
authors.initials: M
authors.lastname: Alam
authors.affiliation: King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
authors.forename: Abdallah
authors.initials: A
authors.lastname: Azzeer
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D005063:Europium / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013818:Thermogravimetry
chemical_list: D002412:Cations; D049408:Luminescent Agents; C044659:molybdate; D005063:Europium; D012822:Silicon Dioxide; D008982:Molybdenum; D002118:Calcium
keywords: Band gap energy; Calcium molybdate nanoparticles; Photoluminescence