Structures and Absorption Spectrum of 1D and 2D ZnS Nanoparticles

2020 ◽  
Vol 5 (1) ◽  
pp. 26-35
Author(s):  
Spyros Papantzikos ◽  
Alexandos G. Chronis ◽  
Fotios I. Michos ◽  
Mihail M. Sigalas
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Toxic Elements ◽  
Visible Region ◽  
Visible Spectrum ◽  
Zns Nanoparticles ◽  
Major Drawback ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Optimized Geometries

Background: ZnS nanoparticles (NPs) are attractive for quantum dots applications because they consist of abundant and non-toxic elements. Their major drawback is that they absorb in the UV region, ultimately limiting their applications. Objective: In the present study, 1D and 2D ZnS NPs have been found. The goal of this study is to find NPs that have absorption in the visible spectrum. Methods: Calculations based on the Density Functional Theory (DFT) have been used to find the optimized geometries. Their absorption spectra have been calculated with the Time-Dependent DFT. Results: Several shapes were examined, such as nanorod, and it is observed that these shapes move the absorption spectra in lower energies, into the visible spectrum, while the 3D NPs have absorption edges in the UV region. Conclusion: NPs with the shape of nanorod in different directions showed that their absorption spectra moved to lower energies well inside the visible spectrum with significantly high oscillator strength. In contrast with the mostly used CdSe NPs, the ZnS NPs are made from more abundant and less toxic elements. Therefore, by making them absorb in the visible region, they may find significant applications in solar cells and other photonic applications.

scholarly journals Quantum Chemical Study of Mixed-Ligand Monometallic Ruthenium(II) Complex of Composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Mohsin Yousuf Lone ◽  
Prakash Chandra Jha
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Mixed Ligand ◽  
Excitation Energies ◽  
Functional Theory ◽  
Effect Of Solvent ◽  
The Density Functional Theory ◽  
Metal Ligand

On the basis of density functional theoretical approach, we have assessed the ground state geometries and absorption spectra of recently synthesized monometallic ruthenium (II) complex of composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O where bpy = 2,2′-bypyridine and H3Imbzim = 4,5-bis(benzimidazol-2-yl)imidazole. The all different kinds of charge transfers such as ligand-ligand, and metal-ligand have been quantified, compared, and contrasted with the experimental results. In addition, the effect of solvent on excitation energies has been evaluated. In spite of some digital discrepancies in calculated and observed geometries, as well as in absorption spectra, the density functional theory (DFT) seems to explain the main features of this complex.

DFT Study of Substituted Effect on Absorption and Emission Spectra of Naphthoquinone Derivatives

2011 ◽  
Vol 233-235 ◽  
pp. 1878-1883 ◽  
Author(s):  
Li Zhi Wang ◽  
Run Zhou Su ◽  
Shuo Qi ◽  
Wei Yu Gong ◽  
Tai Min Cheng
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Visible Region ◽  
Emission Spectra ◽  
Electron Transition ◽  
Functional Theory ◽  
Absorption And Emission ◽  
Absorption And Emission Spectra ◽  
The Density Functional Theory ◽  
Substituted Effect

The density functional theory (DFT) is used to compute the ground-state geometries of naphthoquinone derivatives, and lowest singlet excited-state geometries of them have been investigated by the singles configuration interaction (CIS) method. The absorption and emission spectra are calculated by time-dependent DFT (TDDFT) on the basis of the ground- and excited-state geometries, respectively. Our calculations are in good agreement with the available experimental results. The calculated results show that with the introduction of hydroxyl the red-shift was found in the absorption and emission, and the range of spectra reach the visible region. Furthermore, in the absorptions electron transition type was identified from the point-view of molecular orbitals. Study of the effect of hydroxyl and site on spectra can provide the helpful information on further designing molecular devices.

Computational study of the optical properties of ZnS nanoparticles

2015 ◽  
Vol 1738 ◽  
Author(s):  
M. M. Sigalas
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Density Functional ◽  
Computational Study ◽  
Time Dependent ◽  
Generalized Gradient ◽  
Zns Nanoparticles ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory

ABSTRACTUsing the density functional theory (DFT) and time dependent DFT, within the generalized gradient approximation (GGA), the electronic and optical properties of stoichiometric (ZnS)n nanoparticles (NP) were calculated. The dependence of the gap on the size (n) of the nanoparticle will be presented. The effect of replacing S atoms with P, Se or Te atoms in the (ZnS)n nanoparticles and its influence in the gap will be also shown.

First-principles study on electronic structure and optical properties of In-doped GaN

2014 ◽  
Vol 13 (08) ◽  
pp. 1450070 ◽  
Author(s):  
Xingxiang Ruan ◽  
Fuchun Zhang ◽  
Weihu Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Solar Spectrum ◽  
Potential Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density

The In -doped GaN is investigated by first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The band structure, electronic structure, density of states and optical properties are investigated. The results indicate that the band-gap becomes narrower and the absorption edge of optical properties is red-shifted with the increase in In -doped concentration. Meanwhile, the visible region has strong absorption properties, and the significant absorption peaks are observed near 3.0 eV and 6.1 eV. The other peaks correspond to the wavelength of absorption spectra from the ultraviolet portion extending to the infrared portion, which almost covers the entire solar spectrum. The studied results show that In -doped GaN can be applied as solar cell and transparent conductivity material.

scholarly journals Theoretical Modelling of High-Resolution X-Ray Absorption Spectra at Uranium M4 Edge

MRS Advances ◽  
2018 ◽  
Vol 3 (53) ◽  
pp. 3143-3148 ◽  
Author(s):  
Jindřich Kolorenč ◽  
Kristina O. Kvashnina
Keyword(s):  
High Resolution ◽  
Absorption Spectra ◽  
Density Functional ◽  
Theoretical Modelling ◽  
Functional Theory ◽  
X Ray ◽  
Impurity Model ◽  
The Density Functional Theory ◽  
Anderson Impurity Model ◽  
X Ray Absorption

ABSTRACTWe investigate the origin of satellite features that appear in the high-resolution x-ray absorption spectra measured at the uranium M4 edge in compounds where the uranium atoms are in the U6+ oxidation state. We employ a material-specific Anderson impurity model derived from the electronic structure obtained by the density-functional theory.

scholarly journals Solar Driven Photocatalytic Activity of Porphyrin Sensitized TiO2: Experimental and Computational Studies

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3131
Author(s):  
Sebastian Otieno ◽  
Anabel E. Lanterna ◽  
John Mack ◽  
Solomon Derese ◽  
Edith K. Amuhaya ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Visible Region ◽  
Solar Spectrum ◽  
Visible Spectrum ◽  
Functional Theory ◽  
Td Dft ◽  
Depth Study ◽  
Photocatalytic H2 Generation

The absence of a secure long-term sustainable energy supply is recognized as a major worldwide technological challenge. The generation of H2 through photocatalysis is an environmentally friendly alternative that can help solve the energy problem. Thus, the development of semiconductor materials that can absorb solar light is an attractive approach. TiO2 has a wide bandgap that suffers from no activity in the visible spectrum, limiting its use of solar radiation. In this research, the semiconductor absorption profile was extended into the visible region of the solar spectrum by preparing porphyrin-TiO2 (P-TiO2) composites of meso-tetra(4-bromophenyl)porphyrin (PP1) and meso-tetra(5-bromo-2-thienyl)porphyrin (PP2) and their In(III), Zn(II) and Ga(III) metal complexes. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed on the porphyrins to gain insight into their electron injection capability. The results demonstrate that P-TiO2 systems merit further in-depth study for applications that require efficient photocatalytic H2 generation.

Theoretical binding affinities and spectra of complexes formed by a cyclic β-peptoid with amino acids

2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Yu Sun ◽  
Jinpei Du ◽  
Ying Wang ◽  
Shi Wu
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Binding Energies ◽  
Basis Set ◽  
Binding Affinities ◽  
Functional Theory ◽  
Guest Molecules ◽  
The Density Functional Theory ◽  
Optimized Geometries

AbstractBinding affinities of a cyclic β-peptoid to amino acids were studied using the density functional theory (DFT) at the B3LYP/6-311G(d,p) level after the basis set superior error (BSSE). The host molecule possesses binding ability to amino acids since the binding energies of the complexes formed are negative. The complexes were stabilized via hydrogen bonds between the host and the guest molecules. Based on the B3LYP/6-31G(d) optimized geometries, electronic spectra of the complexes were calculated using the INDO/CIS method. 13C NMR spectra and nucleus-independent chemical shift (NICS) values of the complexes were computed at the B3LYP/6-31G(d) level. Carbon atoms in the carboxyl groups of the complexes are shifted downfield relative to those of the host. Some complexes exhibit aromaticity although the host shows anti-aromaticity. Formation of hydrogen bonds leads to cyclic current formation in these complexes.

scholarly journals Structural modulation of π-conjugated linkers in D–π–A dyes based on triphenylamine dicyanovinylene framework to explore the NLO properties

2021 ◽  
Vol 8 (8) ◽  
pp. 210570
Author(s):  
Muhammad Khalid ◽  
Muhammad Usman Khan ◽  
Iqra Shafiq ◽  
Riaz Hussain ◽  
Akbar Ali ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Optical Materials ◽  
Density Functional ◽  
Visible Region ◽  
Functional Theory ◽  
Nlo Properties ◽  
Structural Modifications ◽  
Nlo Response ◽  
Nlo Materials ◽  
Structural Modulation

A donor–π–acceptor type series of Triphenylamine–dicyanovinylene-based chromophores ( DPMN1–DPMN11 ) was designed theoretically by the structural tailoring of π-linkers of experimentally synthesized molecules DTTh and DTTz to exploit changes in the optical properties and their nonlinear optical materials (NLO) behaviour. Density functional theory (DFT) computations were employed to understand the electronic structures, absorption spectra, charge transfer phenomena and the influence of these structural modifications on NLO properties. Interestingly, all investigated chromophores exhibited lower band gap (2.22–2.60 eV) with broad absorption spectra in the visible region, reflecting the remarkable NLO response. Furthermore, natural bond orbital (NBO) findings revealed a strong push–pull mechanism in DPMN1–DPMN11 as donor and π-conjugates exhibited positive, while all acceptors showed negative values. Examination of electronic transitions from donor to acceptor moieties via π-conjugated linkers revealed greater linear (〈 α 〉 = 526.536–641.756 a.u.) and nonlinear ( β tot = 51 313.8–314 412.661 a.u.) response. It was noted that the chromophores containing imidazole in the second p-linker expressed greater hyperpolarizability when compared with the ones containing pyrrole. This study reveals that by controlling the type of π-spacers, interesting metal-free NLO materials can be designed, which can be valuable for the hi-tech NLO applications.

Sign in / Sign up

Export Citation Format

Share Document