scholarly journals Comprehensive modeling of the band gap and absorption spectrum of BiVO4

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Julia Wiktor ◽  
Igor Reshetnyak ◽  
Francesco Ambrosio ◽  
Alfredo Pasquarello
Keyword(s):  
Absorption Spectrum ◽  
Band Gap ◽  
Comprehensive Modeling

ChemInform Abstract: Anomalous Band Gap Behavior in Mixed Sn and Pb Perovskites Enables Broadening of Absorption Spectrum in Solar Cells.

ChemInform ◽  
2014 ◽  
Vol 45 (40) ◽  
pp. no-no
Author(s):  
Feng Hao ◽  
Constantinos C. Stoumpos ◽  
Robert P. H. Chang ◽  
Mercouri G. Kanatzidis
Keyword(s):  
Absorption Spectrum ◽  
Solar Cells ◽  
Band Gap

Effect of intrinsic point defects on ZnO electronic structure and absorption spectra

2020 ◽  
Vol 34 (17) ◽  
pp. 2050147
Author(s):  
Yuqin Guan ◽  
Qingyu Hou ◽  
Danyang Xia
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Band Gap ◽  
Absorption Spectra ◽  
Point Defects ◽  
Formation Energy ◽  
Stable Structure ◽  
Impurity Level ◽  
Intrinsic Point Defects ◽  
Rich Condition

The effect of intrinsic point defects on the electronic structure and absorption spectra of ZnO was investigated by first-principle calculation. Among the intrinsic point defects in ZnO, oxygen vacancies [Formula: see text] and interstitial zinc [Formula: see text] have the lower formation energy and the more stable structure under zinc(Zn)-rich condition, whereas zinc vacancies [Formula: see text] and interstitial oxygen [Formula: see text] have the lower formation energy and the more stable structure under oxygen(O)-rich condition. The band gap of [Formula: see text] becomes narrow and the absorption spectrum has a redshift. In the visible region, the photo-excited electron transition of [Formula: see text] is graded from the valence band top to the impurity level and then to the conduction band bottom, showing the redshift of absorption spectrum of [Formula: see text] and explaining the reason of [Formula: see text] forming a deep impurity levels in ZnO. Moreover, the impurity energy level of [Formula: see text] coincides with the Fermi level, indicating the significant trap effect and the slow recombination of electrons and holes, which are conducive to the design and preparation of novel ZnO photocatalysts. The band gap of [Formula: see text] and [Formula: see text] broadened and the absorption spectrum showed blueshift, explaining the different values of the ZnO band gap width.

Tuning the binding energy of excitons in the MoS2 monolayer by molecular functionalization and defective engineering

2020 ◽  
Vol 22 (21) ◽  
pp. 11936-11942
Author(s):  
Kangli Wang ◽  
Beate Paulus
Keyword(s):  
Absorption Spectrum ◽  
Binding Energy ◽  
Optical Absorption ◽  
Band Gap ◽  
Optical Absorption Spectrum ◽  
Exciton Binding Energy ◽  
Electronic Band ◽  
Mos2 Monolayer ◽  
Electronic Band Gap

Using the DFT-GW-BSE method, we analyze how the electronic band gap, optical absorption spectrum and exciton binding energy of the MoS2 monolayer are influenced by NO and C3H3N3 molecules and S-defects.

Anomalous Band Gap Behavior in Mixed Sn and Pb Perovskites Enables Broadening of Absorption Spectrum in Solar Cells

2014 ◽  
Vol 136 (22) ◽  
pp. 8094-8099 ◽  
Author(s):  
Feng Hao ◽  
Constantinos C. Stoumpos ◽  
Robert P. H. Chang ◽  
Mercouri G. Kanatzidis
Keyword(s):  
Absorption Spectrum ◽  
Solar Cells ◽  
Band Gap

Electrical Properties and UV-Visual Spectra of (Na0.535K0.48) NbO3 Ceramics Doped with Bi2O3 and Fe2O3

2010 ◽  
Vol 177 ◽  
pp. 194-196
Author(s):  
Yong Qin Liu ◽  
Zhao Quan Gong ◽  
Li Ma ◽  
Dong Fang Xu ◽  
Da Zhi Sun
Keyword(s):  
Absorption Spectrum ◽  
Electrical Properties ◽  
Band Gap ◽  
Doping Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Process

(Na0.535K0.48) NbO3 ceramics doped with Bi2O3•Fe2O3 are prepared by a ceramic process. The effect of Bi3+ and Fe3+ on microstructure and electrical properties of ceramics is investigated. X-ray diffraction shows that the structure of the material is perovskite. The conductivity of ceramics increases with the doping content. UV-Visual absorption spectrum is affected by doping Bi3+ and Fe3+. The mechanism of conductivity is discussed with respect to energy of band-gap in the system.

scholarly journals Band Gap Characterization of Thermally Treated Hybrid Blend ZnPc/CdS Thin Films

2019 ◽  
Vol 17 (43) ◽  
pp. 94-102
Author(s):  
Holya A. Alobaidy
Keyword(s):  
Thin Films ◽  
Absorption Spectrum ◽  
Band Gap ◽  
Annealing Time ◽  
Spin Coating ◽  
Energy Gap ◽  
Conductivity Measurement ◽  
Cds Thin Films ◽  
Optical Behavior

Spin coating technique used to prepare ZnPc, CdS and ZnPc/CdS blend thin films, these films annealed at 423K for 1h, 2h and 3h. Optical behavior of these films were examined using UV-Vis. and PL. The absorption spectrum of ZnPc shows a decreasing in absorption with the increase of annealing time while CdS spectrum give a clearly absorption peak at~510 nm. Energy gap of ZnPc increases from 1.41 to 1.52 eV by increasing the annealing time. Eg of CdS decrease by increasing annealing time, from 2.3 eV to 2.2 eV. The intensities of the peaks obtained from PL spectra were strongly dependent on annealing time and confirmed the results obtained from UV-Vis. D.C. conductivity measurement showed that all the thin films have two different activation energies in the temperature range 303–473K.

scholarly journals Influence of Air Annealing and Gamma Ray Irradiation on the Optical Properties of Cl16FePc Thin Films

2012 ◽  
Vol 9 (4) ◽  
pp. 2439-2445 ◽  
Author(s):  
Raji Koshy ◽  
C. S. Menon
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Optical Absorption ◽  
Band Gap ◽  
Gamma Ray ◽  
Optical Transition ◽  
High Electron ◽  
Glass Substrates ◽  
Optical Dielectric Constant

Metal phthalocyanines are one of the most promising candidates to be used in the fabrication of such devices. Among various phthalocyanines, Iron Hexadecachloro Phthalocyanine (Cl16FePc) has received less attention. Basic characteristics of Cl16FePc are not reported in literature. Hexadecacholoro phthalocyanines have attracted interest as possible n-type organic semiconductor with high electron mobility and good stability characteristics. In the present work we investigate the optical band gap of the Cl16FePc thin films from the optical absorption spectrum as a function of air annealing temperatures and their suitability for the fabrication of molecular electronic devices. Some optical properties of the samples were studied as a function of γ-radiation doses also. Optical transition is found to be of direct type and optical band gaps are determined by analyzing the absorption spectrum. Vacuum sublimed thin films of Iron hexadecachloro phthalocyanine were prepared at room temperature onto glass substrates at a base pressure of 10-5Torr on precleaned glass substrates using Hind Hivac 12A4 coating plant. The optical energy band gap Eg were calculated. The mechanism of optical absorption follow the rule of direct transition. In the present paper we also report refractive index, real and imaginary parts of optical dielectric constant etc. from the reflectance measurements.

scholarly journals First-principles study on the effect of high Mn doped on the band gap and absorption spectrum of ZnO

2013 ◽  
Vol 62 (3) ◽  
pp. 037101
Author(s):  
Hou Qing-Yu ◽  
Dong Hong-Ying ◽  
Ying Chun ◽  
Ma Wen
Keyword(s):  
Absorption Spectrum ◽  
Band Gap ◽  
First Principles ◽  
First Principles Study ◽  
Mn Doped
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