Effect of Praseodymium Species on the Structural and Functional Properties of Nanocrystalline BiFeO3 Powders and Thin Films

2012 ◽  
Vol 1454 ◽  
pp. 39-44
Author(s):  
Gina Montes Albino ◽  
Marco Gálvez-Saldaña ◽  
Oscar Perales-Pérez
Keyword(s):  
Thin Films ◽  
Crystallite Size ◽  
Functional Properties ◽  
Doping Level ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ferroelectric Behavior ◽  
Structural And Functional Properties

ABSTRACTThe present study addressed the effect of the incorporation of Praseodymium species in the BiFeO3(BFO) structure on the corresponding structural and functional properties of powders and films. The level of the doping species varied from 0 at% to 4 at%. BFO powders and thin films were synthesized by a sol-gel method, where glycol was aggregated to the main solvent to increase the viscosity of the precursor solutions and promote their adhesion onto platinum substrates. The development of the host BFO structure was confirmed by XRD analyses of samples annealed at 700°C for one hour (powders) or 500°C for 2 hours (thin films), in air. The average crystallite size varied from 37 nm to 41 nm and 28nm to 40nm for powders and thin films, respectively, due to the increase of the doping level. The incorporation of specific dopant species played an important role in the ferromagnetic and ferroelectric behavior in the material.

Effect of Ca and Ag doping on the functional properties of BiFeO3 nanocrystalline powders and films

2014 ◽  
Vol 1675 ◽  
pp. 105-111 ◽  
Author(s):  
Gina Montes Albino ◽  
Oscar Perales-Pérez ◽  
Boris Renteria-Beleño ◽  
Yarilyn Cedeño-Mattei
Keyword(s):  
Thin Films ◽  
Functional Properties ◽  
Bismuth Ferrite ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Nitrogen Atmosphere ◽  
Nanocrystalline Powders ◽  
Systematic Evaluation ◽  
Gel Method ◽  
Structural And Functional Properties

ABSTRACTThe present work addresses the systematic evaluation of the influence of the incorporation of dopant species (Ca+2, Ag+1) on the structural and functional properties of bismuth ferrite (BFO) nanocrystalline powders and films. Pure and doped BFO powders and thin films were synthesized by a modified sol-gel method. The concentration of the doping species varied from 0 up to 7 at %. The development of the host BFO structure was confirmed by XRD analyses of samples annealed at 700°C for one hour in air and nitrogen atmosphere. Thicknesses of films varied between 80 and 200 nm, depending on the concentration of Ca+2 species. Doped BFO exhibited a magnetic behavior that turned from paramagnetic into ferrimagnetic with the increase of Ca+2 concentrations.

scholarly journals Au-TiO2 Synthesized by a Microwave- and Sonochemistry-Assisted Sol-Gel Method: Characterization and Application as Photocatalyst

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1052 ◽  
Author(s):  
Rafael Hernández ◽  
José Rosendo Hernández-Reséndiz ◽  
Marisela Cruz-Ramírez ◽  
Rodrigo Velázquez-Castillo ◽  
Luis Escobar-Alarcón ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Sol Gel ◽  
Synthesis Method ◽  
Physicochemical Characterization ◽  
Average Crystallite Size ◽  
Spherical Particles ◽  
One Pot ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Value

Titanium dioxide (TiO2) is a widely used and well studied photocatalyst synthesized using different methodologies, including sol-gel, which allows one to modify the material in a one-pot step. By using a microwave- and sonochemistry-assisted sol-gel method, x wt.% Au-TiO2 photocatalysts were successfully synthesized. Physicochemical characterization of the photocatalysts shows an average crystallite size of 10.5 nm and an even morphological distribution of spherical particles with the sonochemistry synthesis method. For the microwave method an average value of crystallite size of 8.3 nm was found and it presents an increase with the amount of Au load. The cyclic voltammetric response and Mott-Schottky analysis are consistent with a semiconductor material containing metallic particles and for a heterophase junction of anatase and brookite with oxygen vacancies, respectively. The photocatalytic activity was assessed by paracetamol degradation in an aqueous solution as model. The sonochemistry-synthesized photocatalysts display the most promising results as they have a better paracetamol removal and the amount of gold in the catalyst (0.7 wt.%) was found to be optimal for this process.

scholarly journals An Amalgam of Mg-Doped TiO2 Nanoparticles Prepared by Sol-Gel Method for Effective Antimicrobial and Photocatalytic Activity

2021 ◽  
Author(s):  
N NITHYA ◽  
S Gopi ◽  
G Bhoopathi
Keyword(s):  
Crystallite Size ◽  
Anatase Phase ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Gram Positive ◽  
Tem Analysis ◽  
Gram Negative ◽  
Gel Method ◽  
Sol Gel Method ◽  
And Shifts

Abstract In this study, undoped and Magnesium doped TiO2 nanoparticles (Mg-TiO2 NPs) were successfully synthesized via a simple sol-gel method cost-effectively. The prepared Mg- TiO2 NPs were characterized by UV-Vis, FTIR, PL, XRD, FESEM, TEM, and EDAX. UV – Visible Spectroscopy showed that an increase in the optical bandgap concerning the concentration of dopant Mg increases. The bandgap values were found to be 3.57-3.54 eV. FTIR spectra showed that the presence of the characteristic stretching and bending vibrational band of Ti – O bonding at 468 cm-1 and shifts in vibrational bands were observed for Mg-TiO2 NPs. PL spectra of Mg- TiO2 NPs at different concentrations exhibit a strong UV emission band. X-ray diffraction confirmed the formation of the tetragonal anatase phase. The average crystallite size of prepared samples was found to be 22-19 nm. The average crystallite size of Mg- TiO2 NPs decreases with increasing the concentration of dopant Mg. The FESEM and TEM analysis confirmed that the spherical morphology for both TiO2 and Mg-TiO2 NPs. SAED pattern confirms the crystalline nature of prepared samples. EDAX spectra confirm the presence of Ti, O, and Mg and confirm that Mg2+ ions are present in the TiO2 lattices. The prepared samples were investigated against gram-positive (B. subtilis and S. aureus) and gram-negative (P. eugenia and K. Pneumonia) bacteria. The prepared samples showed potent antibacterial activity against gram-negative bacteria than the gram-positive bacteria. The prepared samples show the excellent photocatalytic degradation for Methylene blue.

scholarly journals Effect of alumina incorporation on restricting grain growth of nanocrystalline tin(IV) oxide

2010 ◽  
Vol 8 (2) ◽  
pp. 331-340 ◽  
Author(s):  
Y. Al-Angari ◽  
M. Kadi ◽  
I. Ismail ◽  
Mohamed. Gabal
Keyword(s):  
Crystallite Size ◽  
Surface Area ◽  
Grain Growth ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Pure Sno2 ◽  
Gel Method ◽  
Sol Gel Method ◽  
Coated Materials ◽  
Average Grain Size

AbstractIn this project, nanocrystalline SnO2 powders were successfully prepared by (a) citrate sol-gel and (b) direct precipitation methods. Powders were characterized using thermal analysis techniques (DTA-TG-DSC), X-ray powder Diffraction (XRD), surface area (BET) and electrical conductivity measurements. XRD patterns showed the presence of the cassiterite structure. SnO2 particles, prepared through sol-gel method exhibit crystallite sizes in the range from 3.1 to 22.3 nm when the gel is heat treated at different temperatures up to 900°C. SnO2 nanocrystallites prepared by the precipitation method are comparatively larger in size. The higher specific surface area was obtained for the powder prepared using sol-gel method and the obtained average grain size (d) is relatively large compared with that of the average crystallite size. The powders show a semiconducting behavior with increasing temperature. The higher conductivity obtained for SnO2 prepared by sol-gel method can be attributed to their smaller average crystallite size. XRD of alumina doped powder exhibits finer particles than pure SnO2. TEM images showed that the particles are spherical in shape and consist of a core of SnO2 surrounded by a coating of alumina. The calculated surface area was found to decrease with temperature increases. Due to the effective role of Al2O3 additive as a grain growth inhibitor for the matrix grains, the observed surface area for the coated materials are predominantly higher than for the uncoated materials.

Fabrication and Characterization of TiO2-Doped ZnAl2O4 Nanocrystals via Sol-Gel Method for GPS Antenna

2016 ◽  
Vol 846 ◽  
pp. 331-344 ◽  
Author(s):  
Huda Abdullah ◽  
Wan Nasarudin Wan Jalal ◽  
Mohd Syafiq Zulfakar ◽  
Mohammad Tariqul Islam ◽  
Badariah Bais ◽  
...  
Keyword(s):  
Thin Films ◽  
Crystallite Size ◽  
Sol Gel ◽  
Microwave Antenna ◽  
Patch Antennas ◽  
Gel Method ◽  
Sol Gel Method ◽  
Direct Band ◽  
Xrd Patterns ◽  
Gps Antenna

The Zn(1-x)TixAl2O4 (x = 0.00, 0.05, 0.15 & 0.25) nanocrystals thin films were prepared by sol-gel method. The properties of Zn(1-x)TixAl2O4 were investigated by X-ray diffraction (XRD), Atomic Force Microscope (AFM), Fourier transform infrared spectra (FTIR) and (UV-Vis). By indexing the XRD patterns, we identified three structural types which is ZnAl2O4, anatase and rutile. The addition of TiO2 increased the crystallite size from 14.65 to 25.25 nm. The direct band gap was found to be around 3.35 to 3.84 eV. The addition of TiO2 increased the crystallite size, surface roughness, and lattice parameters of the resultant films, evidently affecting their density and dielectric constant (). The thin films were characterized in the certain frequency to determine the using LCR spectrometer. The and density value of the Zn(1-x)TixAl2O4 films increase linearly from 8.56 to 13.48 and 4.60 to 4.70 g/cm3 with the increasing of x value, respectively. Based on the material analysis and microwave antenna theory, GPS patch antennas were fabricated using the Zn(1-x)TixAl2O4 material. The fabricated GPS antenna with the highest (13.48) material exhibits the smallest size of antenna which is 7.45 cm2. The performances and the operating frequencies were measured using a PNA series network analyzer. The result showed that all patch antennas operate at frequency of 1.570 GHz. The GPS patch antenna fabricated from Zn0.25Ti0.75Al2O4 showed an excellent combination of return loss (-29.6 dB), smallest size (7.85 cm2), and wide bandwidth (195 MHz). All fabricated antennas are meets the requirements of GPS applications.

Fe2O3 - TiO2 THIN FILMS PREPARED BY SOL-GEL METHOD

2011 ◽  
Vol 10 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Ramona-Crina Suciu ◽  
Marcela Corina Rosu ◽  
Teofil Danut Silipas ◽  
Emil Indrea ◽  
Violeta Popescu ◽  
...  
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Gel Method ◽  
Sol Gel Method
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