scholarly journals A Novel Poly{(2,5-diyl furan) (benzylidene)}: A New Synthetic Approach and Electronic Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Abdelkader Belmokhtar ◽  
Ahmed Yahiaoui ◽  
Aïcha Hachemaoui ◽  
Benyoucef Abdelghani ◽  
Nabahat Sahli ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Conjugated Polymer ◽  
Optical Band Gap ◽  
Synthetic Approach ◽  
Polar Solvents ◽  
Simple Method ◽  
Sheet Silicate ◽  
Ft Ir ◽  
Silicate Clay

A new conjugated aromatic poly[(furan-2, 5-diyl)-co-(benzylidene)] has been prepared by polycondensation of benzaldehyde and furan catalyzed by Maghnite-H+. Maghnite-H+ is a montmorillonite sheet silicate clay, which exchanged with protons. These polymers can be dissolved in high polar solvents such as DMSO, DMF, THF, or CHCl3 A kind of band-gap conjugated poly[(furan-2, 5-diyl)-co-(benzylidene)] has been synthesized by a simple method and characterized by 1HNMR, 13CNMR, FT-IR, and UV-Vis. The result reveals that the band-gap of the PFB conjugated polymer has an optical band gap of 2.2 eV.

Formation of a-Si:H Film by p-CVD Method with SiH4-He Mixture and its Opto-Electronic Properties

1995 ◽  
Vol 377 ◽  
Author(s):  
Youichi Nakamura ◽  
Tsuyoshi Yamaguchi ◽  
Atsushi Okagawa
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Optical Band Gap ◽  
Emission Spectra ◽  
Optical Emission ◽  
High Deposition Rate ◽  
Hydrogen Dilution ◽  
Rf Glow Discharge ◽  
Helium Dilution ◽  
Ft Ir

ABSTRACTFormation of hydrogenated amorphous silicon (a-Si:H) was carried out by rf glow discharge method in the reactive gas systems of silane. By preliminary experiments on a-Si:H for helium dilution, a relatively high deposition rate up to 2–3 μm/hr was obtained. In order to investigate the opto-electronic properties on a-Si:H films due to different dilution of helium or hydrogen, measurements on optical band gap Eop, electric conductivity and FT-IR were done. Optical emission spectra were also observed. Optical band gap value Eop on a-Si:H film for SiH4 (10%) -He (90%) was nearly constant about 1.73 eV, while that for SiH4 (10%) -H2 (90%) was increased from 1.75 eV to 1.78 eV with increase of residence time of silane molecule and it was relatively high. From the experimental results of FT-IR, ratio of bonding mode of SiH to (SiH+SiH2) for hydrogen dilution was about 90% and higher than that for helium dilution, while hydrogen concentration in the film for SiH4 (10%) -H2 (90%) was less than 10% and that for SiH4 (10%) -He (90%) was 20–30%.

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.

scholarly journals Thermal, Electrical, and Optical Properties of Synthesized (1E, 2E)-(4-bromophenyl)(hydroxyimino)acetaldehyde Oxime Complexes

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Emin Karapinar ◽  
Orhan Karabulut ◽  
Nazan Karapinar
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Conductivity Measurements ◽  
Energy Band Gap ◽  
Temperature Dependent ◽  
Electrical And Optical Properties ◽  
Analysis Techniques ◽  
Temperature Dependent Conductivity ◽  
Ft Ir ◽  
Thermal Analysis Techniques

The (1E, 2E)-(4-bromophenyl)(hydroxyimino)acetaldehyde oxime complexes, [ML2], M = Co(II), Cu(II), and Ni(II), were synthesized and characterized by elemental analysis, magnetic susceptibility, FT-IR spectra, and thermal analysis techniques. The optical band gap of this ligand and its complexes were determined by UV-vis spectrophotometer in the wavelength range 300–800 nm. A decrease in the energy band gap of the [CoL2], [NiL2], and [CuL2] complexes has been observed compared with LH ligand. Temperature-dependent conductivity measurements showed that all samples behave like semiconductor. Activation energies calculated from Arrhenius plots showed that the conduction occurs via both intramolecular and the intermolecular processes.

Structure and Optical Properties of Quantum Confined Pure and Cu Doped SnO2

2020 ◽  
Vol 1159 ◽  
pp. 60-66
Author(s):  
J.R. Sheeba ◽  
Sathasivam Radhika ◽  
C.M. Padma
Keyword(s):  
Band Gap ◽  
Tin Oxide ◽  
Optical Band Gap ◽  
Green Emission ◽  
Precipitation Method ◽  
Rutile Structure ◽  
Tetragonal Rutile Structure ◽  
Ft Ir ◽  
Tin Oxide Nanoparticles ◽  
Co Precipitation

Pure and copper doped tin oxide nanoparticles were synthesized by co-precipitation method and are characterized by XRD, SEM, EDAX, UV-Visible, photoluminescence, and FT-IR analysis techniques. Tetragonal rutile structure is confirmed from XRD and the crystallite size is found to be between 3.8nm and 4.8nm. The optical band gap is observed from UV-Vis spectrum and is found to be 3.99eV and 3.93eV for tin oxide and copper doped tin oxide respectively. The optical band gap of pure and Copper doped tin oxide were blue shifted due to quantum confinement. Photoluminescence spectrum shows UV, blue and green emission peaks.

Crystal structure, electronic properties and optical band gap of KLa(1−x)Eux(PO3)4

2014 ◽  
Vol 609 ◽  
pp. 222-227 ◽  
Author(s):  
M. Ferhi ◽  
K. Horchani-Naifer ◽  
C. Bouzidi ◽  
H. Elhouichet ◽  
M. Ferid
Keyword(s):  
Crystal Structure ◽  
Band Gap ◽  
Electronic Properties ◽  
Optical Band Gap

scholarly journals Preparation and characterization of silver orthophosphate photocatalytic coating on glass substrate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masahide Hagiri ◽  
Kenichi Uchida ◽  
Mika Kamo Sasaki ◽  
Shofiyah Sakinah
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Glass Substrate ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Photocatalytic Ability ◽  
X Ray ◽  
Glass Substrates ◽  
Elemental Silver

AbstractThe photocatalytic activity of silver orthophosphate Ag3PO4 has been studied and shown to have a high photo-oxidation capability. However, there is few reported example of a simple method to prepare Ag3PO4 coatings on various substrates. In this study a novel and simple method to immobilize Ag3PO4 on the surface of glass substrates has been developed. A silver phosphate paste based on a polyelectrolyte solution was applied to a smooth glass surface. The resulting dried material was calcined to obtain a coating that remained on the glass substrate. The coating layer was characterized by X-ray diffraction and energy dispersive X-ray spectrometry, and the optical band gap of the material was determined. The results indicated that an Ag3PO4 coating responsive to visible light was successfully prepared. The coating, under visible light irradiation, has the ability to decompose methylene blue. Although the coating contained some elemental silver, this did not adversely affect the optical band gap or the photocatalytic ability.

Excitonic Contribution of Nanosilicon on Light Emitting Properties

2011 ◽  
Vol 364 ◽  
pp. 308-312
Author(s):  
Sib Krishna Ghoshal ◽  
M.R. Sahar ◽  
M. Supar Rohani
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Size Dependence ◽  
Optical Band Gap ◽  
Surface States ◽  
Light Emitting ◽  
Optical And Electronic Properties ◽  
Pl Intensity ◽  
Excitonic Effects ◽  
Si Quantum Dots

A phenomenological model is developed by integrating the effect of excitonic energy states, localized surface states and quantum confinement (QC) to obtain an analytical expression for the room temperature photoluminescence (PL) intensity. We calculate the binding energy of strongly confined excitons in silicon (Si) quantum dots (QD) having sizes 1 to 7.75 nm to examine its contribution on optical band gap and electronic properties. The band gap with excitonic contribution is found to decrease as much as 0.23 eV for the smallest dot. The effect of exciton states explains almost accurately the experimental PL data. Our model provides the mechanism for controlling the PL intensity through fitting parameters. Huge excitonic effects, which depend strongly on QD size and shape, characterize the optical spectra. The results for the size dependence of the optical band gap, the PL intensity, and oscillator strength are presented the role excitonic effects on optical and electronic properties are discussed.

Theoretical investigation of the structure and electronic properties of poly(dithieno[3,4-b:3',4'-d]thiophene), a small-band-gap conjugated polymer

1993 ◽  
Vol 26 (6) ◽  
pp. 1260-1264 ◽  
Author(s):  
C. Quattrocchi ◽  
R. Lazzaroni ◽  
J. L. Bredas ◽  
R. Zamboni ◽  
C. Taliani
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Theoretical Investigation ◽  
Conjugated Polymer ◽  
Small Band

Influence of Oxygen to Argon Ratio on the Optical Band Gap of Bi3.25La0.75Fe1Ti2O12 Thin Films Deposited by RF Sputtering

2015 ◽  
Vol 15 (10) ◽  
pp. 8228-8232
Author(s):  
Jun Young Han ◽  
Chung Wung Bark
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Oxygen Content ◽  
Optical Band Gap ◽  
Rf Sputtering ◽  
Wide Band ◽  
Perovskite Oxides ◽  
Wide Band Gap ◽  
Visible Absorption ◽  
Simple Method

Achieving wide band gap tunability in ferroelectric perovskite oxides is desirable for the development of photovoltaic device applications and solar cells. To tune the wide band gap of perovskite oxides, ferroelectric iron doped BLT thin films (BLFT) on SrTiO3 substrates were fabricated by RF sputtering with simple control of the oxygen content. The structural and optical properties were analyzed by X-ray diffraction, scanning electron microscopy and ultraviolet-visible absorption spectroscopy. As the oxygen content in the mixed Ar+O2 atmosphere was increased from 0% to 50%, the optical band gap of the thin films were decreased from 2.8 eV to 2.64 eV. The BLFT film deposited at an Ar/O2 ratio of 1/1 exhibited a significantly lower optical band gap than the other samples. This simple sputtering approach to controlling the band gap with a simple method can provide a new candidate tool for manipulating optoelectronics devices.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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