scholarly journals Structural, Magnetic and Photocatalytic Properties of BiFeO3 Nanoparticles

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Seyyed Morteza Masoudpanah
Keyword(s):  
Thermal Decomposition ◽  
Band Gap ◽  
Optical Band Gap ◽  
Visible Region ◽  
Spherical Shape ◽  
Phase Evolution ◽  
Weak Ferromagnetism ◽  
Visible Light Photocatalyst ◽  
Bifeo3 Nanoparticles ◽  
Vis Spectroscopy

Single phase BiFeO3 nanoparticles as a visible light photocatalyst were successfully synthesized by thermal decomposition of the glyoxylate precursor. The glyoxylate precursors were formed by the redox reaction between ethylene glycol and nitrate ions. The phase evolution, structure and optical properties of BiFeO3 nanoparticles were characterized by X-ray diffraction, electron microscopy and UV–Vis spectroscopy methods. The BiFeO3 nanoparticles showed the quasi spherical shape. The BiFeO3 nanoparticles synthesized at 500 °C showed the weak ferromagnetism behavior, due to the size confinement effect, in spite of the antiferromagnetic behavior of the BiFeO3 nanoparticles synthesized at 600 °C. The BiFeO3 nanoparticles exhibited strong absorption in the visible region with the optical band gap calculated from Tauc’s plot. The optical band gap decreased from 2.10 to 2.08 eV by the increasing of thermal decomposition temperature. Moreover, the BiFeO3 nanoparticles were used for the degradation of methylene blue as a typical dye pollutant under direct sunlight irradiation.

scholarly journals Effect of thickness on the optical properties of Gaas thin films

2013 ◽  
Vol 37 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Chitra Das ◽  
Jahanara Begum ◽  
Tahmina Begum ◽  
Shamima Choudhury
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Band Gap ◽  
Optical Band Gap ◽  
Visible Region ◽  
Solar Spectrum ◽  
Band Gap Energy ◽  
Optical Parameters ◽  
Gap Energy

Effect of thickness on the optical and electrical properties of gallium arsenide (GaAs) thin films were studied. The films of different thicknesses were prepared by vacuum evaporation method (~10-4 Pa) on glass substrates at a substrate temperature of 323 K. The film thickness was measured in situ by a frequency shift of quartz crystal. The thicknesses were 250, 300 and 500 nm. Absorption spectrum of this thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2500 nm. The values of some important optical parameters of the studied films (absorption coefficient, optical band gap energy and refractive index; extinction co-efficient and real and imaginary parts of dielectric constant) were determined using these spectra. Transmittance peak was observed in the visible region of the solar spectrum. Here transmittance showed better result when thicknesses were being increased. The optical band gap energy was decreased by the increase of thickness. The refractive index increased by increasing thickness while extinction co-efficient and real and imaginary part of dielectric constant decreased. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15684 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 83-91, 2013

scholarly journals Synthesis of Fluorene Based Alternating Copolymers using Direct Arylation Polymerization

2021 ◽  
Vol 33 (2) ◽  
pp. 393-398
Author(s):  
Mohd Sani Sarjadi ◽  
Yap Leong Khen ◽  
Xin Lin Wong ◽  
Zuhair Jamain ◽  
Md Lutfor Rahman
Keyword(s):  
Solar Cell ◽  
Band Gap ◽  
Active Layer ◽  
Optical Band Gap ◽  
Direct Arylation ◽  
Low Band Gap ◽  
Alternating Copolymers ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Direct Arylation Polymerization

Many researches have been done to obtain a low band gap and high Polymeric solar cell (PSCs) polymer either by creating new polymer or revising reported polymers from previous studies. In present work, two new copolymers were synthesized through direct arylation polymerization to produce poly(9,9-didodecylfluorene-alt-benzo[c][1,2,5]thiadiazole (P1) and poly(9,9-didodecylfluorene-altthieno[ 3,2-b]thiophene) (P2). The P1 and P2 are donor-accepter copolymers. P1 and P2 were compared to investigate its suitability to be applied in PSCs. The polymers obtained were characterized using FT-IR, NMR and UV-Vis spectroscopy. P1 shows two adsorption bands at λmax1 = 243 nm and λmax2 = 320 nm, whereas P2 also shows two adsorption bands at λmax1 = 243 nm and λmax2 = 427 nm. The optical band gap was calculated, P1 enabled band gap of 3.88 eV while P2 showed band gap of 2.91 eV. This work could be provided an insight to design and synthesize more efficient fluorene-based copolymers as active layer of PSCs in due course.

Synthesis, Characterization and Properties of Conjugated Poly(1-Alkyl-2,5-Pyrrylene Vinylene)

1997 ◽  
Vol 488 ◽  
Author(s):  
In Tae Kim ◽  
Ronald L. Elsenbaumer
Keyword(s):  
Molecular Weight ◽  
Conjugated Polymers ◽  
Band Gap ◽  
Organic Solvents ◽  
Optical Band Gap ◽  
Vis Spectroscopy ◽  
Electrical Conductivities ◽  
C Nmr

AbstractA series of poly(N-alkylpyrrylene vinylenes)( alkyl = methyl(l), hexyl(2), dodecyl(3)) have been synthesized from the monomer, N-alkyl-2,5-bis(thiophenylmethylene)pyrrole, by base induced elimination and polymerization. The resulting deep purple conjugated polymers (2, 3) were soluble in a variety organic solvents. The electrical conductivities of the polymers lie in the range, 10−2 to 2.5 S/cm. The highest yield was obtained when the polymers were synthesized in refluxing THF with a monomer/ base mole ratio of 1/4. The optical band gap of the undoped polymers were 1.89 eV(1), 1.69 eV(2) and 1.65 eV(3). Characterization of the polymers includes IR, CV, 1H and 13C NMR, UV-vis spectroscopy, TGA and molecular weight studies.

Effect of Samarium Ions on Physical and Optical Properties of Zinc Borotellurite Glass System

2021 ◽  
Vol 317 ◽  
pp. 100-108
Author(s):  
Siti Nasuha Mohd Rafien ◽  
Azman Kasim ◽  
Norihan Yahya ◽  
Azhan Hashim ◽  
Wan Aizuddin Wan Razali
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Molar Volume ◽  
Optical Band Gap ◽  
Urbach Energy ◽  
Glass System ◽  
X Ray Diffraction ◽  
Indirect Transition ◽  
Vis Spectroscopy ◽  
Amorphous Nature

Modifying the physical and optical properties of zinc borotellurite glasses by controlling rare earth (RE) doping is important in order to obtain high quality glass. In this study, Samarium (Sm3+) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique with chemical composition (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%). The physical properties by mean of their density as well as molar volume were measured while the optical properties have been studied through UV-Vis spectroscopy in order to determine the optical band gap (Eopt) and Urbach energy (ΔΕ) of the glass system. Optical absorption spectra of the glass samples were recorded in the range 350 nm - 750 nm at room temperature. The amorphous nature of the glass was confirmed from X-ray diffraction techniques. The density and molar volume of the glass samples were found to vary with respect to Sm3+ ions content. The value of optical band gap, Eopt lies between 2.605 eV to 2.982 eV for the direct transition and 2.768 eV to 3.198 eV for the indirect transition respectively. Meanwhile, the Urbach energy, ΔE was observed in the range of 0.112 eV to 0.694 eV respectively. The physical and optical properties were found to be strongly affected by the varying concentration of Sm3+ ions. Some other results will be analysed and discussed in detail.

The Role of Acid Concentration on Band Gap Shrinkage in Cellulose Nanocrystals Fabricated from Water Hyacinth

2022 ◽  
pp. 1-3
Author(s):  
Jack A Adem ◽  
◽  
John O Agumba ◽  
Godfrey O Barasa ◽  
Angeline A Ochung ◽  
...  
Keyword(s):  
Band Gap ◽  
Acid Concentration ◽  
Cellulose Nanocrystals ◽  
Optical Band Gap ◽  
Impurity Band ◽  
Band Gap Energy ◽  
Phase Identification ◽  
Hydrolysis Time ◽  
Gap Energy ◽  
Vis Spectroscopy

In this study, the fingerprint of the acid concentration during the hydrolysis process on the optical band gap of cellulose nanocrystals (CNCs) has been systematically studied. The CNCs have been prepared using hydrochloric acid at a hydrolysis temperature of 50°C and at a constant hydrolysis time of 4 hours but with varying hydrochloric cid concentrations of 5%, 10% and 15%. The crystalline structure and phase identification of the CNCs have been studied using XRD technique. UV-Vis Spectroscopy has been done and the optical band gap energy calculated by performing the Tauc’s plot. From the study, the grain size has been found to decrease with acid concentration while the band gap energy has been found to increase with increasing acid concentration. Further, the optical band gaps of the CNCs have been found to decrease with the increase in crystallite size. This shrinkage of the band gap has been attributed to the increased impurity concentration leading to the narrowing of the band gap due to the emerging of the impurity band formed by the overlapped impurity states

scholarly journals Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2979 ◽  
Author(s):  
Dana S. Muhammed ◽  
Mohamad A. Brza ◽  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Sarkawt A. Hussen ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Optical Absorption ◽  
Band Gap ◽  
Optical Band Gap ◽  
Electron Transition ◽  
Nano Particles ◽  
Optical Absorption Coefficient ◽  
Vis Spectroscopy ◽  
Non Destructive ◽  
Non Destructive Techniques

The structure and optical properties of polyethylene oxide (PEO) doped with tin titanate (SnTiO3) nano-filler were studied by X-ray diffraction (XRD) and UV-Vis spectroscopy as non-destructive techniques. PEO-based composed polymer electrolytes inserted with SnTiO3 nano-particles (NPs) were synthesized through the solution cast technique. The change from crystalline phase to amorphous phase of the host polymer was established by the lowering of the intensity and broadening of the crystalline peaks. The optical constants of PEO/SnTiO3 nano-composite (NC), such as, refractive index (n), optical absorption coefficient (α), dielectric loss (εi), as well as dielectric constant (εr) were determined for pure PEO and PEO/SnTiO3 NC. From these findings, the value of n of PEO altered from 2.13 to 2.47 upon the addition of 4 wt.% SnTiO3NPs. The value of εr also increased from 4.5 to 6.3, with addition of 4 wt.% SnTiO3. The fundamental optical absorption edge of the PEO shifted toward lower photon energy upon the addition of the SnTiO3 NPs, confirming a decrement in the optical band gap energy of PEO. The band gap shifted from 4.78 eV to 4.612 eV for PEO-doped with 4 wt.% SnTiO3. The nature of electronic transitions in the pure and the composite material were studied on the basis of Tauc’s model, while optical εi examination was also carried out to calculate the optical band gap.

Zn1–xCdxO Microtubes: Synthesis and Optical Properties Using Direct Microwave Irradiation

2017 ◽  
Vol 36 (9) ◽  
pp. 921-926
Author(s):  
Qusay A. H. Al-Naser ◽  
Jian Zhou ◽  
Guizhen Liu ◽  
Lin Wang
Keyword(s):  
Microwave Irradiation ◽  
Optical Band Gap ◽  
Energy Dispersive Spectrometer ◽  
Visible Region ◽  
Average Diameter ◽  
Emission Peak ◽  
Strong Emission ◽  
Uv Emission ◽  
Vis Spectroscopy ◽  
Irradiation Field

AbstractHexagonal Zn1–xCdxO microtubes with CdO contents (x = 0, 1, 3 and 5 %) have been successfully synthesized via direct microwave irradiation. Field emission scanning electron microscopy (FE-SEM), UV–vis spectroscopy, photoluminescence (PL), and energy-dispersive spectrometer (EDS) were employed to characterize the Zn1–xCdxO microtubes. Zn1–xCdxO microtubes have an average diameter of 140 µm, wall thickness of 2~4 µm and length of about 250 µm. UV–vis studies showed that the optical band gap of ZnO microtube (3.27 eV) was reduced to 3.20 eV for Zn0.97Cd0.03O microtube. The PL spectra showed a strong emission peak in the visible region centered at 562.88 nm with a weak UV emission has been detected for Zn0.97Cd0.03O microtube. EDS confirms the presence of Zn and O in ZnO microtube and the absence of Cd as a doping material for CdO-doped ZnO microtubes due to the small amounts of CdO concentration.

scholarly journals Characterization and Optical Properties of MnO Doped CuO-Containing Phosphate Glass as Absorption Filters

2018 ◽  
Vol 15 ◽  
pp. 5983-5996
Author(s):  
Hytham Ahmed Abd El-Ghany
Keyword(s):  
Band Gap ◽  
Phosphate Glass ◽  
Optical Band Gap ◽  
Visible Region ◽  
Glass Network ◽  
Spectroscopic Studies ◽  
Progressive Increase ◽  
Cutoff Wavelength ◽  
Xrd Patterns

In order to demonstrate the intrinsic and extrinsic changes induced by MnO in the phosphate glass network, a glass system of composition 44P2O5-38ZnO-2CuO-(16-x)Na2O-xMnO (where, x = 1, 2, 3, 4, and 5 mol%) was prepared using the conventional melt quenching technique. XRD patterns confirmed the non-crystalline nature of the prepared samples. The density and molar volume as a function of MnO content were determined to characterize structure of the obtained glasses. The optical spectroscopic studies of the prepared samples were carried out over (190-1000 nm) spectral range. The prepared samples were found to behave as bandpass filters in the visible region of spectrum. The UV cutoff wavelength was shifted from 308 nm to 352 nm by increasing content of MnO which is very useful in the optical technology requirements such as ultraviolet preventing applications and the protection from UV-LASER. The optical band gap was decreased by increasing content of MnO whilst, the Urbach energy was increased. The decrease in optical band gap was attributed to the progressive increase in non-bridging oxygens (NBOs) concentration with the addition of MnO. The refractive index was found to be enhanced with the addition of MnO by the effect of increase in overall polarizability. However, the optical polarizability was found to be correlated to the chemical composition of the glass. The results reveal the role of MnO as a network modifier in the phosphate glass matrix.

Transparent Conductive In-doped Cd3TeO6 Thin Films with Perovskite Structure Deposited by Radio Frequency Magnetron Sputtering

2005 ◽  
Vol 20 (9) ◽  
pp. 2256-2260 ◽  
Author(s):  
Hiroyuki Tetsuka ◽  
Yue Jin Shan ◽  
Keitaro Tezuka ◽  
Hideo Imoto ◽  
Kiyotaka Wasa
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Band Gap ◽  
Indium Tin Oxide ◽  
Optical Band Gap ◽  
Visible Region ◽  
Radio Frequency Magnetron ◽  
Radio Frequency Magnetron Sputtering ◽  
Average Transmittance

Transparent conductive In-doped Cd3TeO6 thin films were deposited on silica glass substrate by radio frequency magnetron sputtering using targets composed of CdO, TeO2, and In2O3 powders, and their electrical and optical properties were examined. The electrical resistivity of 3.2 × 10−3 Ωcm and an average transmittance above 80% in the visible region (400–800 nm) were obtained for the films deposited at the substrate temperature above 300 °C. The maximum optical band gap was 3.92 eV for the film deposited at 700 °C, demonstrating a large optical band gap comparable to indium tin oxide.

Sign in / Sign up

Export Citation Format

Share Document