Syntheses and characterization of three new sulfides with large band gaps: acentric Ba4Ga4SnS12, centric Ba12Sn4S23 and Ba7Sn3S13

2017 ◽  
Vol 46 (43) ◽  
pp. 14771-14778 ◽  
Author(s):  
Rui-Huan Duan ◽  
Peng-Fei Liu ◽  
Hua Lin ◽  
Shang-Xiong Huangfu ◽  
Li-Ming Wu
Keyword(s):  
Band Gap ◽  
Band Gaps ◽  
First Time

Three new sulfides with large band gaps, NCS Ba4Ga4SnS12, CS Ba12Sn4S23 and Ba7Sn3S13 were synthesized for the first time. Ba4Ga4SnS12 exhibits a desired balance between the band gap (2.90 eV) and the SHG intensity (34 × KDP).

Extremal Characterization of Band Gaps in Nonlinear Gratings

2003 ◽  
Vol 12 (02) ◽  
pp. 135-148 ◽  
Author(s):  
E. van Groesen ◽  
A. Sopaheluwakan
Keyword(s):  
Finite Element ◽  
Band Gap ◽  
Oblique Incidence ◽  
Band Gaps ◽  
Simple Criterion ◽  
Variational Characterization ◽  
Finite Element Scheme ◽  
Element Scheme ◽  
Comparison Arguments

In this paper we present an explicit extremal characterization of the edges of the lowest band gap in gratings; we restrict here to the case of TE-modes, but the TM case can be treated similarly. The characterization is valid for linear and Kerr-nonlinear gratings, for smooth as well as for step-variations of the index and the coefficient of nonlinearity. The variational characterization allows one to derive monotonicity properties by using simple comparison arguments. For instance, the monotonic shift of the band gap as a function of the angle of oblique incidence is proved, leading to a simple criterion for omni-directionally for the band gap. Rough estimates of the band gaps can be obtained by substituting suitable trial fields in the governing functionals, while the same formulation can also be used to design a Finite Element scheme for accurate calculations.

A study on K2SbF2Cl3 as a new mid-IR nonlinear optical material: new synthesis and excellent properties

2015 ◽  
Vol 3 (37) ◽  
pp. 9588-9593 ◽  
Author(s):  
Yin Huang ◽  
Xianggao Meng ◽  
Pifu Gong ◽  
Zheshuai Lin ◽  
Xingguo Chen ◽  
...  
Keyword(s):  
Band Gap ◽  
Hydrothermal Method ◽  
Nonlinear Optical ◽  
Optical Band Gap ◽  
Band Gaps ◽  
Optical Material ◽  
Nonlinear Optical Material ◽  
New Synthesis ◽  
First Time

K2SbF2Cl3 is synthesized by the hydrothermal method, and its potential is evaluated for the first time. Its powders show a phase-matchable SHG effect 4 times that of KDP. Its optical band gap is 4.01 eV which is much wider than the band gaps of the currently commercialized IR NLO crystals.

Synthesis and characterization of acceptor–donor–acceptor-based low band gap small molecules containing benzoselenadiazole

2016 ◽  
Vol 94 (6) ◽  
pp. 553-558 ◽  
Author(s):  
Baji Shaik ◽  
Jin-Hee Han ◽  
Dong Jin Song ◽  
Hun-Min Kang ◽  
Sang-Gyeong Lee
Keyword(s):  
Thermal Stability ◽  
Small Molecules ◽  
Band Gap ◽  
Nitrile Group ◽  
Band Gaps ◽  
Synthesis And Characterization ◽  
Low Band Gap ◽  
Good Thermal Stability ◽  
Donor Acceptor

Acceptor–donor–acceptor-type compounds 5′,5″-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3′-dodecyl-2,2′-bithiophene-5-carbonitrile) (9) and 4,4′-(5,5′-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3-dodecylthiophene-5,2-diyl))dibenzonitrile (10) were designed and synthesized. These compounds differ in terminal positions, compound 9 with a thiophene-containing nitrile group and compound 10 with a phenyl-containing nitrile group. Both compounds have shown good thermal stability and low band gap. The band gaps of compounds 9 and 10 were 1.74 and 1.83 eV, respectively. These results indicate that they are promising materials for use in optoelectronics.

scholarly journals DFT modeling of polyaniline: A computational investigation into the structure and band gap of polyaniline

2021 ◽  
Author(s):  
Kevin M Scotland ◽  
Oliver K.L. Strong ◽  
Mark Parnis ◽  
Andrew James Vreugdenhil
Keyword(s):  
Band Gap ◽  
Dft Method ◽  
Band Gaps ◽  
Basis Set ◽  
Structural Motif ◽  
Synthetic Method ◽  
Computational Investigation ◽  
Structural Units ◽  
Dft Modeling ◽  
First Time

The band gaps of three forms of polyaniline (PANI) are calculated using the DFT method with the B3LYP functional and SV(P) basis set. This marks the first time that the band gap for this polymer has been calculated using this DFT method. The calculations include an investigation of the effect of varying the benzoid-quinoid structural units, the effect of increasing oligomer length and the inclusion of Michael’s addition structures which could be residual in the polymer depending on the chosen synthetic method. All results were compared to the experimentally determined band gap of 1.5 eV as typically reported in the literature. A commonly used structural motif of alternating benzoid-quinoid units and a ratio of 0.5:0.5 benzoid: quinoid resulted in a computed band gap of 1.9 eV. Inclusion of one extra quinoid unit gave rise to a band gap of 1.3 eV. Incorporation of a Michael’s addition structure was found to dominate the band gap calculation, yielding a localized LUMO and a band gap of 1.3 eV that was insensitive to the polymer chain length and composition.

Analysis of Periodicity Termination in Phononic Crystals

2011 ◽  
Author(s):  
Bruce L. Davis ◽  
Andrew S. Tomchek ◽  
Edgar A. Flores ◽  
Liao Liu ◽  
Mahmoud I. Hussein
Keyword(s):  
Band Gap ◽  
Timoshenko Beam ◽  
Periodic Structures ◽  
Beam Theory ◽  
Phononic Crystals ◽  
Timoshenko Beam Theory ◽  
Band Gaps ◽  
Pass Band ◽  
Unit Cells

While resonant propagation modes are non-existent within band gaps in infinite periodic structures, it is possible for anomalous band-gap resonances to appear in finite periodic structures. We establish two criteria for the characterization of band-gap resonances and propose approaches for their elimination. By considering flexural periodic beams, we show that as the number of unit-cells is increased the vibration response corresponding to band-gap resonances (1) does not shift in frequency, and (2) drops in amplitude. Both these outcomes are not exhibited by regular pass-band resonances, nor by resonances in finite homogenous beams when the length is changed. Our conclusions stem from predictions based on Timoshenko beam theory coupled with matching experimental observations.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

Preparation and Characterization of Polyvinylidene Fluoride/ZrO2-TiO2 Optical Film with Wide Band Gap and High Refractive Index

2013 ◽  
Vol 28 (6) ◽  
pp. 671-676 ◽  
Author(s):  
Yu-Qing ZHANG ◽  
Li-Li ZHAO ◽  
Shi-Long XU ◽  
Chao ZHANG ◽  
Xiao-Ying CHEN ◽  
...  
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Polyvinylidene Fluoride ◽  
Wide Band ◽  
High Refractive Index ◽  
Wide Band Gap ◽  
Optical Film

Chemical Constituents and Antibacterial Activity of Cissus Aralioides.

2020 ◽  
Vol 17 ◽  
Author(s):  
Balogun Olaoye Solomon ◽  
Ajayi Olukayode Solomon ◽  
Owolabi Temitayo Abidemi ◽  
Oladimeji Abdulkarbir Oladele ◽  
Liu Zhiqiang
Keyword(s):  
Plant Extract ◽  
Chemical Constituents ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Sub Saharan Africa ◽  
Chromatographic Purification ◽  
Whole Plant ◽  
Sub Saharan ◽  
First Time

: Cissus aralioides is a medicinal plant used in sub-Saharan Africa for treatment of infectious diseases; however the chemical constituents of the plant have not been investigated. Thus, in this study, attempt was made at identifying predominant phytochemical constituents of the plant through chromatographic purification and silylation of the plant extract, and subsequent characterization using spectroscopic and GC-MS techniques. The minimum inhibitory concentration (MICs) for the antibacterial activities of the plant extract, chromatographic fractions and isolated compounds were also examined. Chromatographic purification of the ethyl acetate fraction from the whole plant afforded three compounds: β-sitosterol (1), stigmasterol (2) and friedelin (3). The phytosterols (1 and 2) were obtained together as a mixture. The GC-MS analysis of silylated extract indicated alcohols, fatty acids and sugars as predominant classes, with composition of 24.62, 36.90 and 26.52% respectively. Results of MICs indicated that friedelin and other chromatographic fractions had values (0.0626-1.0 mg/mL) comparable with the standard antibiotics used. Characterization of natural products from C. aralioides is being reported for the first time in this study.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

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