scholarly journals Synthesis of Lead-Free CaTiO3 Oxide Perovskite Film through Solution Combustion Method and Its Thickness-Dependent Hysteresis Behaviors within 100 mV Operation

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5446
Author(s):  
Subin Lee ◽  
Soyeon Kwak ◽  
Taehyun Park ◽  
Byoungchul Son ◽  
Hyung Joong Yun ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Low Voltage ◽  
Metal Structure ◽  
Combustion Method ◽  
Lead Free ◽  
Morphological Properties ◽  
Free Calcium ◽  
Solution Combustion ◽  
X Ray

Perovskite is attracting considerable interest because of its excellent semiconducting properties and optoelectronic performance. In particular, lead perovskites have been used extensively in photovoltaic, photodetectors, thin-film transistors, and various electronic applications. On the other hand, the elimination of lead is essential because of its strong toxicity. This paper reports the synthesis of lead-free calcium titanate perovskite (CaTiO3) using a solution-processed combustion method. The chemical and morphological properties of CaTiO3 were examined as a function of its thickness by scanning electron microscopy, X-ray diffraction (XRD), atomic force microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible spectrophotometry. The analysis showed that thicker films formed by a cumulative coating result in larger grains and more oxygen vacancies. Furthermore, thickness-dependent hysteresis behaviors were examined by fabricating a metal-CaTiO3-metal structure. The electrical hysteresis could be controlled over an extremely low voltage operation, as low as 100 mV, by varying the grain size and oxygen vacancies.

Augmentation of ferromagnetism in CuO–Al2O3 nanocomposite synthesized via solution combustion method

2019 ◽  
Vol 9 (6) ◽  
pp. 653-659 ◽  
Author(s):  
Mir Waqas Alam ◽  
Farooq Ahmad Dar ◽  
Fida Mohmed ◽  
Abdullah Aljaafari ◽  
Osama Saber
Keyword(s):  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Finite Size ◽  
Combustion Method ◽  
Cuo Nanoparticles ◽  
Finite Size Effect ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
Microscopy Imaging ◽  
X Ray

The finite size effect of CuO nanoparticles and their effect on the magnetic behavior of a CuO–Al2O3 nanocomposite synthesized via a solution combustion method are discussed here. It is observed that the introduction of CuO nanoparticles of ∼20 nm in size on the surfaces of Al2O3 nanosheets strongly influences the magnetic moment of the nanocomposite. The X-ray diffraction pattern reveals the presence of a CuO phase in the CuO–Al2O3 nanocomposite. Electron microscopy imaging shows the presence of CuO nanoparticles distributed over the surfaces of Al2O3 nanosheets. Magnetic measurements performed at 5 and 300 K revealed a strong enhancement in the saturation magnetization of the CuO–Al2O3 nanocomposite at both temperatures. This increase is due to the formation of CuO nanoparticles on the surfaces of the Al2O3 nanosheets. These CuO nanoparticles show a ferromagnetic nature due to the uncompensated surface Cu2+ spins of the copper ions. The presence of the Cu2+ state in the CuO nanoparticles in the CuO–Al2O3 nanocomposite was confirmed by X-ray photoelectron spectroscopy (XPS) measurements.

scholarly journals Efficient Removal of Levofloxacin by Activated Persulfate with Magnetic CuFe2O4/MMT-k10 Nanocomposite: Characterization, Response Surface Methodology, and Degradation Mechanism

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3583
Author(s):  
Junying Yang ◽  
Minye Huang ◽  
Shengsen Wang ◽  
Xiaoyun Mao ◽  
Yueming Hu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Photoelectron Spectroscopy ◽  
Degradation Mechanism ◽  
Sol Gel ◽  
Combustion Method ◽  
Copper Ferrite ◽  
X Ray ◽  
Rsm Model

In this study, a magnetic copper ferrite/montmorillonite-k10 nanocomposite (CuFe2O4/MMT-k10) was successfully fabricated by a simple sol-gel combustion method and was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunner–Emmett–Teller (BET) method, vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS). For levofloxacin (LVF) degradation, CuFe2O4/MMT-k10 was utilized to activate persulfate (PS). Due to the relative high adsorption capacity of CuFe2O4/MMT-k10, the adsorption feature was considered an enhancement of LVF degradation. In addition, the response surface methodology (RSM) model was established with the parameters of pH, temperature, PS dosage, and CuFe2O4/MMT-k10 dosage as the independent variables to obtain the optimal response for LVF degradation. In cycle experiments, we identified the good stability and reusability of CuFe2O4/MMT-k10. We proposed a potential mechanism of CuFe2O4/MMT-k10 activating PS through free radical quenching tests and XPS analysis. These results reveal that CuFe2O4/MMT-k10 nanocomposite could activate the persulfate, which is an efficient technique for LVF degradation in water.

scholarly journals Hydrothermal Synthesis of Iodine-Doped Nanoplates with Enhanced Visible and Ultraviolet-Induced Photocatalytic Activities

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jiang Zhang ◽  
Zheng-Hong Huang ◽  
Yong Xu ◽  
Feiyu Kang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Diffuse Reflectance Spectroscopy ◽  
Synergetic Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities

The iodine-doped Bi2WO6(I-BWO) photocatalyst was prepared via a hydrothermal method using potassium iodide as the source of iodine. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of I-BWO for the degradation of rhodamine B (RhB) was higher than that of pure BWO and I2-BWO regardless of visible light (>420 nm) or ultraviolet light (<400 nm) irradiation. The results of DRS analysis showed that the I-BWO and I2-BWO catalysts had narrower band gaps. XPS analysis proved that the multivalent iodine species including I0and were coadsorbed on the defect surface of Bi2WO6in I-BWO. The enhanced PL intensity revealed that a large number of defects of oxygen vacancies were formed by the doping of iodine. The enhanced photocatalytic activity of I-BWO for degradation of RhB was caused by the synergetic effect of a small crystalline size, a narrow band gap, and plenty of oxygen vacancies.

scholarly journals Ferromagnetic Properties of N-Doped and Undoped TiO2 Rutile Single-Crystal Wafers with Addition of Tungsten Trioxide

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1934 ◽  
Author(s):  
Jing Xu ◽  
Haiying Wang ◽  
Zhongpo Zhou ◽  
Zhaorui Zou
Keyword(s):  
Magnetic Properties ◽  
Single Crystal ◽  
Saturation Magnetization ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Tio2 Surface ◽  
Doped Tio2 ◽  
X Ray ◽  
N Doping ◽  
Tio2 Rutile

In this work, undoped, N-doped, WO3-loaded undoped, and WO3-loaded with N-doped TiO2 rutile single-crystal wafers were fabricated by direct current (DC) magnetron sputtering. N-doping into TiO2 and WO3 loading onto TiO2 surface were used to increase and decrease oxygen vacancies. Various measurements were conducted to analyze the structural and magnetic properties of the samples. X-ray diffraction results showed that the N-doping and WO3 loading did not change the phase of all samples. X-ray photoelectron spectroscopy results revealed that W element loaded onto rutile single-crystal wafers existed in the form of WO3. UV-Vis spectrometer results showed that the absorption edge of WO3-loaded undoped and WO3-loaded with N-doped TiO2 rutile single-crystal wafers had red shift, resulting in a slight decrease in the corresponding band gap. Photoluminescence spectra indicated that oxygen vacancies existed in all samples due to the postannealing atmosphere, and oxygen vacancies density increased with N-doping, while decreasing with WO3 loading onto TiO2 surface. The magnetic properties of the samples were investigated, and the saturation magnetization values were in the order N-doped > WO3-loaded with N-doped > undoped > WO3-loaded undoped rutile single-crystal wafers, which was the same order as the oxygen vacancy densities of these samples. N-doping improved the saturation magnetization values, while WO3-loaded decreased the saturation magnetization values. This paper reveals that the magnetic properties of WO3-loaded with N-doped rutile single-crystal wafers originate from oxygen vacancies.

Facile Synthesis of Lead-Free Piezoelectric Sodium Niobate (NaNbO3) Powders via the Solution Combustion Method

2011 ◽  
Vol 415 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Nopsiri Chaiyo ◽  
Anucha Ruangphanit ◽  
Banjong Boonchom ◽  
Naratip Vittayakorn
Keyword(s):  
Combustion Method ◽  
Lead Free ◽  
Sodium Niobate ◽  
Facile Synthesis ◽  
Solution Combustion ◽  
Solution Combustion Method

Morphology of Silver Thin Films Deposited on TiO2(110) Surfaces

1998 ◽  
Vol 05 (01) ◽  
pp. 387-392 ◽  
Author(s):  
D. Abriou ◽  
D. Gagnot ◽  
J. Jupille ◽  
F. Creuzet
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Two Dimensional ◽  
Silver Films ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Silver Deposits ◽  
Silver Thin Films

The growth mode of silver films deposited at room temperature on TiO 2(110) surfaces has been examined by means of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum (UHV) conditions, On clean vacancy-free TiO 2(110) surfaces, 0.1-nm-thick (on average) Ag deposits form a two-dimensional (2D) layer. When the thickness of the silver overlayer is increased, 3D clusters are shown to appear while the 2D film is preserved, furthermore, the influence of surface oxygen vacancies on the growth of Ag/TiO 2(110) is evidenced by well-characterized differences in the morphology of 9-nm-thick silver deposits.

scholarly journals Characterization of MgO:Cd thin films grown by SILAR method

2018 ◽  
Vol 96 (7) ◽  
pp. 804-809 ◽  
Author(s):  
Harun Güney ◽  
Demet İskenderoğlu
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Soda Lime ◽  
Morphological Properties ◽  
Emission Region ◽  
Soda Lime Glass ◽  
Silar Method ◽  
Soda Lime Glass Substrate ◽  
X Ray ◽  
Cd Doping

The undoped and 1%, 2%, and 3% Cd-doped MgO nanostructures were grown by SILAR method on the soda lime glass substrate. X-ray diffractometer (XRD), ultraviolet–visible spectrometer, scanning electron microscope, photoluminescence (PL), and X-ray photoelectron spectroscopy measurements were taken to investigate Cd doping effects on the structural, optical, and morphological properties of MgO nanostructures. XRD measurements show that the samples have cubic structure and planes of (200), (220) of MgO and (111), (200), and (220) of CdO. It was observed that band gaps increase with rising Cd doping rate in MgO thin film. The surface morphology of samples demonstrates that MgO nanostructures have been affected by the Cd doping. PL measurements show that undoped and Cd-doped MgO thin films can radiate in the visible emission region.

scholarly journals Air Annealing Effect on Oxygen Vacancy Defects in Al-doped ZnO Films Grown by High-Speed Atmospheric Atomic Layer Deposition

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5043
Author(s):  
Chia-Hsun Hsu ◽  
Xin-Peng Geng ◽  
Wan-Yu Wu ◽  
Ming-Jie Zhao ◽  
Xiao-Ying Zhang ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
High Speed ◽  
Oxygen Vacancies ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Zno Films ◽  
X Ray ◽  
Layer Deposition

In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 °C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 °C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 °C can further remove the oxygen defects introduced mid-gap states.

scholarly journals Enhancing Short-Term Plasticity by Inserting a Thin TiO2 Layer in WOx-Based Resistive Switching Memory

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 908 ◽  
Author(s):  
Hyojong Cho ◽  
Sungjun Kim
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Short Term Memory ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
X Ray ◽  
Short Term Plasticity ◽  
Good Retention

In this work, we emulate biological synaptic properties such as long-term plasticity (LTP) and short-term plasticity (STP) in an artificial synaptic device with a TiN/TiO2/WOx/Pt structure. The graded WOx layer with oxygen vacancies is confirmed via X-ray photoelectron spectroscopy (XPS) analysis. The control TiN/WOx/Pt device shows filamentary switching with abrupt set and gradual reset processes in DC sweep mode. The TiN/WOx/Pt device is vulnerable to set stuck because of negative set behavior, as verified by both DC sweep and pulse modes. The TiN/WOx/Pt device has good retention and can mimic long-term memory (LTM), including potentiation and depression, given repeated pulses. On the other hand, TiN/TiO2/WOx/Pt devices show non-filamentary type switching that is suitable for fine conductance modulation. Potentiation and depression are demonstrated in the TiN/TiO2 (2 nm)/WOx/Pt device with moderate conductance decay by application of identical repeated pulses. Short-term memory (STM) is demonstrated by varying the interval time of pulse inputs for the TiN/TiO2 (6 nm)/WOx/Pt device with a quick decay in conductance.

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