Red‐Emitting Magnetic Nanocomposites Assembled from Ag‐Decorated Fe3O4@SiO2 and Y2O3:Eu3+: Impact of Iron‐Oxide/Silver Nanoparticles on Eu3+ Emission. Issue 4 (29th January 2018)

• Record Type: Journal Article
• Authors: Khan, Latif U.; Zambon, Luis F. M.; Santos, Jacinete L.; Rodrigues, Rodrigo V.; Costa, Luelc S.; Muraca, Diego; Pirota, Kleber R.; Felinto, Maria C. F. C.; Malta, Oscar L.; Brito, Hermi F.
• Is Part Of: ChemistrySelect. Volume 3:Issue 4(2018)
• Page Start: 1157
• Page End: 1167
• Publication Date: 2018-01-29
• Subjects: Iron oxides/Silver -- Y2O3:Eu3+ -- Luminescence -- Magnetism -- Nanocomposites; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201702478
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: The new multistep approach for co‐assembling magnetic iron oxide nanoflowers with red‐emitting Y2 O3 :Eu 3+ to form luminescent and magnetic nanocomposites was reported. The Fe3 O4 core prepared by solvothermal method was layered by SiO2 shell and decorated with small size spherical Ag nanoparticles as well as further coated with Y2 O3 :Eu 3+ luminophore. The nanoflower shape Fe3 O4 core of size ∼110 nm and crystalline cubic structure of bifunctional iron‐oxide@Y2 O3 :Eu 3+, Fe3 O4 @SiO2 @Y2 O3 :Eu 3+ and Fe3 O4 @SiO2 ‐Ag@Y2 O3 :Eu 3+ (1 mol%) nanomaterials were confirmed from X‐rays diffraction, EDS spectra and transmission electron microscopy (TEM) images. The static magnetic measurements supported and manifested nonsuperparamagnetic behavior of the materials at 300 K. The iron oxides are usually luminescence quenchers. In order to rationalize this effect, their optical properties based on their emission spectral data and luminescence decay curves were studied. Experimental intensity parameters (Ωλ ), lifetimes (τ), intrinsic quantum yield ( Q L n L n ) as well as radiative (Arad ) and non‐radiative (Anrad ) decay rates were calculated to probe the local chemical environment of the Eu 3+ ion and to better understand the phenomena of iron oxide induced luminescence quenching. The highest value of the intrinsic quantum yield ( Q L n L n =74%) for the α‐Fe2 O3 @Y2 O3 :Eu 3+ (1 mol%) among all the luminescent and magnetic nanocomposites suggests that α‐Fe2 O3 phase induces a lower luminescence quenching then Fe3 O4 /γ‐Fe2 O3 . The SiO2 thin layer leads to improve the luminescence efficiency, whereas the Ag nanoparticles act as luminescence quencher. These novel Eu 3+ nanomaterials may act as a red emitting layer for magnetic and light converting molecular devices. Abstract : The Fe3 O4 and Ag nanoparticles act as luminescence quencher when the Eu 3+ ion is in contact or close proximity to these particles. This result is indicated by the lower values of intrinsic quantum yield( Q L n L n ) for the Fe3 O4 @SiO2 ‐Ag@Y2 O3 :Eu 3+ and Fe3 O4 @Y2 O3 :Eu 3+ (1 mol%) nanocomposites, when compared to the Y2 O3 :Eu 3+ (1 mol%) nanophospor. In addition, α‐Fe2 O3 @Y2 O3 :Eu 3+ (1 mol%) exhibits high value of Q L n L n among all the magneto‐luminescent nanomaterials, suggesting that α‐Fe2 O3 phase induces lower luminescence quenching compared to γ‐Fe2 O3 /Fe3 O4 phases.