Structural and optical properties of KNN nanoparticles synthesized by a sol–gel combustion method

2017 ◽  
Vol 31 (15) ◽  
pp. 1750175 ◽  
Author(s):  
Gh. H. Khorrami ◽  
M. Mousavi ◽  
M. Dowran

In this paper, potassium sodium niobate (KNN) nanopowders were successfully obtained by sol–gel combustion method. According to thermogravimetric analysis (TGA) results, the produced xerogel was calcined at 500[Formula: see text]C, 600[Formula: see text]C, and 700[Formula: see text]C to obtain KNN powders. The structural and optical properties of the prepared powders were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and UV–vis spectroscopy. The XRD patterns indicated formation of orthorhombic KNN samples. The Scherrer formula and size–strain plot (SSP) method were employed to calculate crystallite size and lattice strain of the KNN powders. The TEM image revealed that the average particle size of the prepared samples is about 30 nm and they have cubic shape. The optical band gap energy of the samples was calculated using UV–vis absorbance spectra of the samples along with Tauc relation.

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 454 ◽  
Author(s):  
A. Méndez-López ◽  
O. Zelaya-Ángel ◽  
M. Toledano-Ayala ◽  
I. Torres-Pacheco ◽  
J.F. Pérez-Robles ◽  
...  

Zirconium oxide (ZrO2) thin films were prepared by the sol-gel dip coating technique, in combination with annealing at different temperatures in air atmosphere, with the final goal of studying the water wettability of the surface. The annealing effects on the structural and optical properties of the ZrO2 films were investigated to check the characteristics of the material. X-ray diffraction (XRD) patterns of ZrO2 annealed at 450 °C and 550 °C show the formation of tetragonal phase, with layers constituted by nanoparticles with average particle size of 21 nm and 25 nm, respectively. Fourier-transform infrared spectroscopy (FT-IR) spectra revealed the presence of vibrational modes associated to ZrO2. Photoluminescence (PL) and ultraviolet-visible spectroscopy (UV–Vis) spectroscopy was used for optical properties. All deposited ZrO2 thin films presented a high optical transparency, with an average transmittance above 70% in the visible range (400–700 nm). The hydrophilic properties of ZrO2 films were characterized by means of the measurements of the contact angle. When the sample was annealed at 550 °C, the hydrophilicity reached the best behavior, which was explained as an effect of the structural and morphological change of the films.


2016 ◽  
Vol 42 (9) ◽  
pp. 10551-10558 ◽  
Author(s):  
Shima Shirinparvar ◽  
Reza Shoja Razavi ◽  
Fatemeh Davar ◽  
Mohammad Reza Loghman-Estarki ◽  
Morteza Hajizadeh-Oghaz ◽  
...  

2021 ◽  
Vol 23 (2) ◽  
pp. e21310965
Author(s):  
Edgar Eduardo Mosquera ◽  
Daniela Herrera-Molina ◽  
Jesús Diosa

TiO2 nanoparticles were successfully synthesized using a facile and scalable sol-gel method and their structural and optical properties studied. XRD ad FTIR was used to identify the phase, crystallite size, and functional groups present in the nanoparticles. The prepared samples crystallize in the anatase structure with highly crystalline order. TEM/EDX shows that the nanoparticles are pure, spherical, and with an average particle size of 15 ± 2 nm. The bandgap energy was 3.59, 3.79, and 3.64 eV, respectively. PL emission is attributed to oxygen vacancies (Vo). The calcination temperature at 450 °C suggests a better photocatalytic performance under visible light compared with other sample's thermal treatments.


2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.


2014 ◽  
Vol 185 ◽  
pp. 86-91 ◽  
Author(s):  
Alexandre R. Bueno ◽  
Renata F.M. Oman ◽  
Paula M. Jardim ◽  
Nicolás A. Rey ◽  
Roberto R. de Avillez

2018 ◽  
Vol 526 (1) ◽  
pp. 187-192 ◽  
Author(s):  
S. B. Bankar ◽  
N. S. Meshram ◽  
N. N. Sarkar ◽  
H. S. Ahamad ◽  
S. J. Dhobale ◽  
...  

2019 ◽  
Vol 33 (10) ◽  
pp. 1950081 ◽  
Author(s):  
Madeeha Riaz ◽  
Rehana Zia ◽  
Snudia Aslam ◽  
Alliya Qamar ◽  
Tousif Hussain ◽  
...  

In this paper, low temperature, economical sol–gel combustion method was adopted to synthesize wollastonite ceramic. Calcium nitrate tetrahydrate and tetraethyl orthosilicate were taken as source for Ca and Si, while citric acid and nitric acid were used as chelating/combustion agents. The yielded powder calcined at 600[Formula: see text]C for 4 h was characterized by FTIR, XRD and SEM techniques. Results showed that the citrate combustion method was the most efficient method to prepare wollastonite at low temperature. Moreover, in vitro bioactivity test performed in simulated body fluid (SBF) showed good bioactivity of synthesized wollastonite ceramics.


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