A study of the effect of morphology on the optical and electrical properties of TiO2 nanotubes for gas sensing applications

2020 ◽  
Vol 90 (3) ◽  
pp. 30102 ◽  
Author(s):  
Alba Arenas-Hernandez ◽  
Carlos Zúñiga-Islas ◽  
Julio César Mendoza-Cervantes
Keyword(s):  
Electrical Properties ◽  
Gas Sensing ◽  
Visible Spectrum ◽  
Electrolyte Solutions ◽  
Band Gap Energy ◽  
Electrochemical Anodization ◽  
Photoluminescence Intensity ◽  
Optical And Electrical Properties ◽  
Resistance Change ◽  
Sensing Applications

In this paper, we report the results of the optical and electrical properties of TiO2 nanotubes with different morphologies for gas sensing applications. Four nanomaterials of TiO2 were prepared by electrochemical anodization using four different electrolyte solutions: 0.255 wt% NH4F with 1 wt%, 3 wt%, 6 wt% and 9 wt% of deionized water in ethylene glycol. Micrographs by scanning electron microscopy (SEM) showed different morphologies caused by the variation in the water content of the solutions. Consequently, as an effect of morphology, the photoluminescence intensity in the visible spectrum was modified. By a change of the crystalline phase of TiO2 nanotubes, the oxygen vacancies increased and affected to the optical and electrical properties of TiO2 films. These films were used for detecting gas at room temperature. Hence, we studied and analyzed the relationship of the morphology, elemental composition, phase composition, band gap energy and defect states as a function of the electrical resistance change of TiO2 nanotubes to understand and improve the sensor response.

Taking advantage of optical and electrical properties of organic molecules for gas sensing applications

2001 ◽  
Vol 393 (1-2) ◽  
pp. 259-266 ◽  
Author(s):  
Tim H. Richardson ◽  
Colin M. Dooling ◽  
Oliver Worsfold ◽  
Liza T. Jones ◽  
Keizo Kato ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Organic Molecules ◽  
Gas Sensing ◽  
Optical And Electrical Properties ◽  
Sensing Applications

OPTICAL AND ELECTRICAL PROPERTIES OF ARGON ION BEAM IRRADIATED PVA/Ag NANOCOMPOSITES

2017 ◽  
Vol 24 (03) ◽  
pp. 1750038 ◽  
Author(s):  
A. M. ABDEL REHEEM ◽  
A. ATTA ◽  
T. A. AFIFY
Keyword(s):  
Silver Nanoparticles ◽  
Electrical Properties ◽  
Ion Beam ◽  
Composite Films ◽  
Band Gap Energy ◽  
Dielectric Measurement ◽  
Optical And Electrical Properties ◽  
Structure Property ◽  
Casting Technique ◽  
Argon Ion

In this work, PVA/Ag nanocomposites films were prepared using solution casting technique, these films were irradiated with Argon ion beam to modify the structure. The main objective of the study is to enhance the optical and electrical properties of the polymer nanocomposites films by irradiation. The conventional characterization techniques such as UV–Visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscope (TEM) and dielectric measurement are employed to understand the structure–property relations. FTIR analysis of these composite films shows chemical changes and a significant impact on them can be observed after irradiation. After doping, the XRD data shows silver nanoparticles formation in the PVA polymer. The band gap energy of samples is decreased with increases in the concentration of silver nanoparticles and ion beam fluence, which gives clear indication that ion beam irradiation induced defects are formed in the composite systems. The electrical conductivity, dielectric loss [Formula: see text] and dielectric constant [Formula: see text] are increased with increasing ion beam fluence and Ag dopant concentration.

SnO2 Nano/Microfibers for Gas Sensors

2020 ◽  
Vol 405 ◽  
pp. 324-329
Author(s):  
Erika Mudra ◽  
Ivan Shepa ◽  
Alexandra Kovalcikova ◽  
Ondrej Milkovič ◽  
Jan Dusza
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Band Gap Energy ◽  
Calcination Process ◽  
Sensing Applications ◽  
Amorphous Nature ◽  
Coating Method ◽  
Type Semiconductor

SnO2 is an n-type semiconductor with the band gap energy of 3.6 eV. It has been widely studied for gas sensing applications, the sensitivity of which can be easily tuned by the operating temperature. The presented paper is focused on the preparation and detailed characterization of the hollow SnO2 nano/microfibers suitable for gas detection sensors. Ceramic SnO2 fibers were produced by needleless electrospinning and followed by the calcination process. The characterization was performed by SEM, TEM, XRD, and Raman spectroscopy. The precursor PVP/SnO2 fibers had amorphous nature. The calcination of the electro spun precursor resulted in the formation of hollow crystalline fibrous structures. The formation mechanism of hollow fibers has been described. Subsequently, a homogeneous fibrous layer was created by the spin coating method for gas sensing applications.

scholarly journals Influence of the La3+, Eu3+, and Er3+ Doping on Structural, Optical, and Electrical Properties of BiFeO3 Nanoparticles Synthesized by Microwave-Assisted Solution Combustion Method

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Angelika Wrzesinska ◽  
Alexander Khort ◽  
Izabela Bobowska ◽  
Adam Busiakiewicz ◽  
Aleksandra Wypych-Puszkarz
Keyword(s):  
Rare Earth ◽  
Electrical Properties ◽  
Bismuth Ferrite ◽  
Solution Combustion Synthesis ◽  
Combustion Method ◽  
Band Gap Energy ◽  
Rare Earth Doping ◽  
Optical And Electrical Properties ◽  
Solution Combustion ◽  
Microwave Assisted

In this study, nanocrystalline (18–28 nm) perovskite-like bismuth ferrite rare earth-doped powders (Bi0.9RE0.1FeO3, where RE = La (BLaFO), Eu (BEuFO), and Er (BErFO)) were obtained by microwave-assisted modification of solution combustion synthesis (SCS). The influence of high load La3+, Eu3+, and Er3+ doping on structural, optical, and electrical properties of BiFeO3 was investigated. It was found that rare earth doping along with fast phase formation and quenching significantly distorts the crystal cells of the obtained materials, which results in the formation of mixed rhombohedral- (R3c-) orthorhombic (Pbnm) crystal structures with decreased lengths of Bi-O and Fe-O bonds along with a decreasing radius size of doping ions. This promotes reduction of the optical band gap energy and suppression of ionic polarization at high frequencies and results in enhanced dielectric permittivity of the materials at 1 MHz.

scholarly journals The effect of annealing temperature on the structural, optical, and electrical properties of CdS films

2010 ◽  
Vol 25 (1) ◽  
pp. 189-196 ◽  
Author(s):  
Hulya Metin ◽  
Mehmet Ari ◽  
Selma Erat ◽  
Semra Durmuş ◽  
Mehmet Bozoklu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Phase Transformation ◽  
Electrical Properties ◽  
Electronic Transport ◽  
Annealing Temperature ◽  
Optical Band Gap ◽  
Urbach Energy ◽  
Band Gap Energy ◽  
Optical And Electrical Properties ◽  
Gap Energy

Cadmium sulfide (CdS) photocatalyst films were grown on glass by chemical bath deposition (pH 9.4, 70 °C) and then annealed in nitrogen from 423 K to 823 K in steps of 100 K. The XRD crystallite size increases in a sigmoidal manner from 60 nm to 100 nm while the optical band gap energy decreases from 2.42 eV to 2.28 eV. This trend is paralleled by the decreasing Urbach energy, but only up to 623 K, where it increases again. This is the temperature where the Cd effectively surpasses the phase transformation from cubic to hexagonal, and the activation energy for electronic transport drops by a factor of nearly two.

Structural characterization, electrical properties and gas sensing applications of polypyrrole/Cu-Al2O3 hybrid nanocomposites

2020 ◽  
Vol 32 (6) ◽  
pp. 719-728 ◽  
Author(s):  
S Sankar ◽  
K Parvathi ◽  
MT Ramesan
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Electrical Properties ◽  
Gas Sensing ◽  
Xrd Analysis ◽  
High Energy ◽  
Dc Conductivity ◽  
Hybrid Nanocomposites ◽  
Ammonia Gas ◽  
Sensing Applications

The present work focused on the synthesis of polypyrrole (PPy) wrapped nano copper-alumina (Cu-Al2O3) composite by an in situ polymerization of pyrrole in the presence of Cu-Al2O3 nanoparticles. The polymerized samples were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The properties such as AC and DC conductivity, dielectric constant, and ammonia gas sensing performance of PPy/Cu-Al2O3 composites were investigated in detail as a function of Cu-Al2O3 content. The FTIR spectra showed the existence of sharp and resolved infrared bands of nanoparticles in the PPy chain. The presence of the crystalline peaks of Cu-Al2O3 in the PPy matrix was confirmed from the XRD analysis. SEM images revealed the homogenous growth of Cu-Al2O3 in the polymer with the formation of spherically shaped particles. The HR-TEM observation showed that Cu-Al2O3 particles were dispersed at a nanometer level in the nanocomposites with a width of 30–60 nm. The glass transition temperature of composites obtained from DSC was found to be increased with increase in the content of nanoparticles. TGA analysis proved that the nano Cu-Al2O3 in the content in the composites acted as a mass transport barrier that retards the degradation of the product. The AC conductivity and dielectric constant of the nanocomposite showed that the maximum electrical properties were observed for the composite with 5 weight percentage loading of Cu-Al2O3. DC conductivity showed that the PPy/Cu-Al2O3 composites have higher electrical conductivity than PPy. The ammonia gas sensing property of the composites was significantly enhanced by the addition of Cu-Al2O3 nanoparticles. Therefore, the improved properties of synthesized PPy/Cu-Al2O3 nanocomposite can be useful for developing functional composite material for the fabrication of sensors, electronic devices, and high energy storage capacitors.

scholarly journals Electrochemical Anodization and Characterization of Titanium Oxide Nanotubes for Photo Electrochemical Cells

2021 ◽  
Vol 2070 (1) ◽  
pp. 012073
Author(s):  
C U Bhadra ◽  
D Henry Raja ◽  
D Jonas Davidson
Keyword(s):  
Titanium Oxide ◽  
Oxygen Vacancies ◽  
Ammonium Fluoride ◽  
Band Gap Energy ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Photoluminescence Intensity ◽  
Titania Nanotube Arrays ◽  
Titanium Oxide Nanotubes ◽  
Inner Diameter

Abstract Due to its multitude of applications, titanium oxide is one of the most coveted and most sought-after materials. The above experiment demonstrated that TiO2 nanotube arrays might be formed by electrochemical anodization of titanium foil. The 0.25 wt% ammonium fluoride (NH4F) was added to a solution of 99% ethylene glycol. Anodization is carried out at a constant DC voltage of 12V for 1 hour. Then, the annealing process is carried out for 1 hour at 4800C, which is known as an annealing. FE-SEM were utilized to evaluate the surface morphology of the nanotube arrays that were made. At the wavelength of 405 nm, sharply peaked photoluminescence intensity was observed, which corresponded tothe band gap energy (3.2 eV) of the anatase TiO2 phase. Since free excitations appear at 391 and 496 nm, and since oxygen vacancies are developed on the surface of titania nanotube arrays, it is reasonable to conclude that free excitations and oxygen vacancies are the causes of humps at 391 and 496 nm, and that they may also be present at 412 and 450 nm. FESEM results showed uniformly aligned TiO2 nanotube arrays with an inner diameter of 100 nm and a wall thickness of 50 nm

W–Ti–O layers for gas-sensing applications: Structure, morphology, and electrical properties

1998 ◽  
Vol 13 (6) ◽  
pp. 1568-1575 ◽  
Author(s):  
L. Sangaletti ◽  
E. Bontempi ◽  
L. E. Depero ◽  
R. Salari ◽  
M. Zocchi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Gas Sensing ◽  
Phase Segregation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Applications ◽  
Structure Morphology ◽  
Structural And Electrical Properties ◽  
Kinetics Of ◽  
Structurally Stable

The kinetics of phase transitions and phase segregation induced by annealing temperature on the Ti–W–O gas-sensing layer was studied by x-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The main goal was to identify, on the basis of kinetics studies, structurally stable Ti–WO3 thin film phases and compare their response to polluting gases in order to determine possible correlations between structural and electrical properties of the sensing layers.

Sign in / Sign up

Export Citation Format

Share Document