Observation of Optical Band-Gap Narrowing and Enhanced Magnetic Moment in Co-Doped Sol–Gel-Derived Anatase TiO2 Nanocrystals

2018 ◽  
Vol 122 (46) ◽  
pp. 26592-26604 ◽  
Author(s):  
V. R. Akshay ◽  
B. Arun ◽  
Guruprasad Mandal ◽  
Geeta R. Mutta ◽  
Anupama Chanda ◽  
...  
Keyword(s):  
Band Gap ◽  
Magnetic Moment ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Anatase Tio2 ◽  
Tio2 Nanocrystals ◽  
Band Gap Narrowing ◽  
Co Doped

Significant reduction in the optical band-gap and defect assisted magnetic response in Fe-doped anatase TiO2 nanocrystals as dilute magnetic semiconductors

2019 ◽  
Vol 43 (15) ◽  
pp. 6048-6062 ◽  
Author(s):  
V. R. Akshay ◽  
B. Arun ◽  
Guruprasad Mandal ◽  
Anupama Chanda ◽  
M. Vasundhara
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Magnetic Behavior ◽  
Anatase Tio2 ◽  
Magnetic Response ◽  
Tio2 Nanocrystals

The nature of BMPs, whether overlapped or isolated, determines the magnetic behavior of Fe-doped TiO2.

scholarly journals Correlation of film thickness to optical band gap of Sol-gel derived Ba0.9Gd0.1TiO3 thin films for optoelectronic applications

2017 ◽  
Vol 162 ◽  
pp. 01042
Author(s):  
Yen Chin Teh ◽  
Ala’eddin A. Saif ◽  
Zul Azhar Zahid Jamal ◽  
Prabakaran Poopalan
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Optoelectronic Applications

THE EFFECT OF HIGH N-DOPED ANATASE TiO2 ON THE BAND GAP NARROWING AND REDSHIFT BY FIRST-PRINCIPLES

2012 ◽  
Vol 26 (27) ◽  
pp. 1250179 ◽  
Author(s):  
QINGYU HOU ◽  
YONGJUN JIN ◽  
CHUN YING ◽  
ERJUN ZHAO ◽  
YUE ZHANG ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Formation Energy ◽  
Doping Concentration ◽  
Covalent Bond ◽  
Anatase Tio2 ◽  
Structure Population ◽  
Densities Of States ◽  
N Doping ◽  
Band Gap Narrowing

Anatase TiO 2 supercells were studied by first-principles, in which one was undoped and another three were high N -doping. Partial densities of states, band structure, population and absorption spectrum were calculated. The calculated results indicated that in the condition of TiO 2-x N x (x = 0.0625, 0.125, 0.25), the higher the doping concentration is, the shorter will be the lattice parameters parallel to the direction of c-axis. The strength of covalent bond significantly varied. The formation energy increases at first, and then decreases. The doping models become less stable as N -doping concentration increases. Meanwhile, the narrower the band gap is, the more significant will be the redshift, which is in agreement with the experimental results.

Effect of compressive stress inducing a band gap narrowing on the photoinduced activities of sol–gel TiO2 films

2011 ◽  
Vol 520 (3) ◽  
pp. 1147-1154 ◽  
Author(s):  
Mohamed N. Ghazzal ◽  
N. Chaoui ◽  
M. Genet ◽  
Eric M. Gaigneaux ◽  
D. Robert
Keyword(s):  
Band Gap ◽  
Compressive Stress ◽  
Sol Gel ◽  
Tio2 Films ◽  
Band Gap Narrowing

INFLUENCE OF ANNEALING TEMPERATURE ON THE CHARACTERISTICS OF NANOCRYSTALLINE SnO2 THIN FILMS PRODUCED BY Sol–Gel AND CHEMICAL BATH DEPOSITION FOR GAS SENSOR APPLICATIONS

2017 ◽  
Vol 24 (07) ◽  
pp. 1750104 ◽  
Author(s):  
SELMA M. H. AL-JAWAD ◽  
ABDULHUSSAIN K. ELTTAYF ◽  
AMEL S. SABER
Keyword(s):  
Band Gap ◽  
Gas Sensor ◽  
Chemical Bath Deposition ◽  
Annealing Temperature ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Dip Coating ◽  
Rutile Structure ◽  
Sensor Applications ◽  
Average Grain Size

Pure nanocrystalline SnO2 films were grown on a clean glass substrate by using sol–gel dip coating and chemical bath deposition (CBD) techniques for gas sensor applications. The films were annealed in air at 300[Formula: see text]C, 400[Formula: see text]C, and 500[Formula: see text]C for 60[Formula: see text]min. The deposited films with a thickness of approximately 300 [Formula: see text] 20 nm were analyzed through X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical absorption spectroscopy. Results revealed that the films produced by dip coating exhibited a tetragonal rutile structure and those produced by CBD showed a tetragonal rutile and orthorhombic structure. The crystalline sizes of the films produced by dip coating annealed at 300[Formula: see text]C, 400[Formula: see text]C, and 500[Formula: see text]C were 8, 14, and 22.34 nm and those for CBD films at these temperatures were 10, 15, and 22 nm, respectively. AFM and SEM results indicated that the average grain size increased as annealing temperature increased. The transmittance and absorbance spectra were then recorded at wavelengths ranging from 300[Formula: see text]nm to 1000[Formula: see text]nm. The films produced by both the methods yielded high transmission at visible regions. The optical band gap energy of dip-coated films also increased as annealing temperature increased. In particular, their optical band gap energies were 3.5, 3.75, and 3.87[Formula: see text]eV at 300[Formula: see text]C, 400[Formula: see text]C, and 500[Formula: see text]C, respectively. By comparison, the energy band gap of CBD-prepared films decreased as annealing temperature increased, and their corresponding band gaps were 3.95, 3.85, and 3.8[Formula: see text]eV at the specified annealing temperatures. The films were further investigated in terms of their sensing abilities for carbon monoxide (CO) gas at 50 ppm by measuring their sensitivity to this gas at different times and temperatures. Our results demonstrated that dip-coated and CBD-prepared films were highly sensitive to CO at 200[Formula: see text]C and 250[Formula: see text]C, respectively.

Modified Sol-Gel Processing of NiCr2O4 Nanoparticles; Structural Analysis and Optical Band Gap

2017 ◽  
Vol 36 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Morteza Enhessari ◽  
Ali Salehabadi ◽  
Salah Khanahmadzadeh ◽  
Kamal Arkat ◽  
Jalal Nouri
Keyword(s):  
Particle Size ◽  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Complexing Agent ◽  
Minor Phase ◽  
Absorption Bands ◽  
Ammonium Dichromate ◽  
Electrical Devices ◽  
Gel Processing

AbstractNickel Chromite nanoparticles were successfully synthesized via a modified sol-gel method using nickel acetate and ammonium dichromate in melted stearic acid as a complexing agent. The diffractograms of the nanoparticles confirmed a pure formation of NiCr2O4 spinel without any minor phase. The coordination structure of as prepared nanoparticles shows a series of absorption bands below 1,000 cm−1 were evidenced the M-O (Cr-O, Ni-O) bond in the sample. Optical band gap, magnetic properties and color parameters (L*.a*.b*) indicates that the final nanoparticles are optically and magnetically active. The particle size of NiCr2O4 was calculated using Scherrer equation at about 24 nm. Optical band gap obtained at 1.7 eV indicating that NiCr2O4 nanoparticles are semiconductor material and can be used in electrical devices.

Blueshift in optical band gap in nanocrystalline Zn1−xCaxO films deposited by sol-gel method

2009 ◽  
Vol 95 (3) ◽  
pp. 031901 ◽  
Author(s):  
Kamakhya Prakash Misra ◽  
R. K. Shukla ◽  
Atul Srivastava ◽  
Anchal Srivastava
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method

Organic–inorganic hybrid thin films based in HfO2 nanoparticles as dielectric for flexible electronics

2014 ◽  
Vol 92 (7/8) ◽  
pp. 806-812 ◽  
Author(s):  
R. Ambrosio ◽  
O. Arciniega ◽  
A. Carrillo ◽  
M. Moreno ◽  
A. Heredia ◽  
...  
Keyword(s):  
Band Gap ◽  
Hybrid Material ◽  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Hafnium Oxide ◽  
Optical Band Gap ◽  
Low Cost ◽  
Sol Gel ◽  
Inorganic Hybrid

In this work the synthesis and characterization of an organic–inorganic hybrid composite film based on hafnium oxide (HfO2) and polyvinylpyrrolidone (PVP) with dielectric properties is presented. These films were prepared using the sol-gel process adjusting the chemical composition to tailor the material properties, such as the dielectric and the optical band gap. The HfO2 was obtained by the hydrolysis of hafnium chloride (HfCl4) under catalysis of ethanol and deionized water, later the PVP was subsequently added to complete the hydrolysis. Finally the films were dried at 150 °C. The structural characterization of the hybrid material showed a hafnium nanoparticle size around 100 nm into the polymer matrix. The chemical structure and the high purity of the hybrid material were corroborated by X-ray photoelectron spectroscopy measurements, which showed the bounding of HfO2–PVP. The electrical characterization demonstrated that the nanostructured materials with hafnium nanoparticles improve the dielectric constant in the films with values around k = 18.5. The optical band gap, Eo, was obtained from 4 to 5.7 eV. These characteristics in our hybrid material are very promising for flexible electronics applications with the advantage of its low temperature, thermal stability, and low cost process of deposition.

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