scholarly journals Effects of Aromatic Thiol Capping Agents on the Structural and Electronic Properties of CdnTen (n = 6,8 and 9) Quantum Dots

2021 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Imran ◽  
Muhammad Jawwad Saif ◽  
Tahir Farooq ◽  
Javed Iqbal

Thiols are efficient capping agents used for the synthesis of semiconductor and metal nanoparticles. Commonly, long-chain thiols are used as passivating agents to provide stabilization to nanoparticles. Theoretical methods rarely reported aromatic thiol ligands’ effects on small-sized CdTe quantum dots’ structural and electronic properties. We have studied and compared the structural and electronic properties of (i) bare and (ii) aromatic thiols (thiophenol, 4-methoxybenzenethiol, 4-mercaptobenzonitrile, and 4-mercaptobenzoic acid) capped CdnTen quantum dots (QDs). Aromatic thiols are used as thiol-radical because of the higher tendency of thiol-radicals to bind with Cd atoms. This work provides an understanding of how the capping agents affect specific properties. The results show that all aromatic thiol-radical ligands caused significant structural distortion in the geometries. The aromatic thiol-radical ligands stabilize LUMOs, stabilize or destabilize HOMOs, and decrease HOMO-LUMO gaps for all the capped QDs. The stabilization of LUMOs is more pronounced than the destabilization of HOMOs. We also studied the effect of solvent on structural and electronic properties. TD-DFT calculations were performed to calculate the absorption spectra of bare and capped QDs, and all the capping ligands resulted in the redshift of absorption spectra.

2014 ◽  
Vol 16 (47) ◽  
pp. 26240-26251 ◽  
Author(s):  
Arnaud Fihey ◽  
François Maurel ◽  
Aurélie Perrier

The structural and electronic properties of dithienylethene photochromic molecules grafted onto a Au25 nanocluster are reviewed and electron/energy transfers are discussed with the help of (TD-)DFT calculations.


2005 ◽  
Vol 19 (15n17) ◽  
pp. 2380-2385 ◽  
Author(s):  
BAOLIN WANG ◽  
DALING SHI ◽  
XIAOSHUANG CHEN ◽  
GUANGHOU WANG ◽  
JIJUN ZHAO

By using Gaussian98 package at BPW91 6-31g(d,p) level combined a genetic algorithm (GA) simulation, we have studied the lowest energy structural and electronic properties of the Al n N ( n =2-13) clusters. The ground-state structures, the charge transfers from Al to N site, HOMO-LUMO gap and the covalent, ionic and metallic nature with cluster size and atomic structure are investigated. Al 7 N , Al 9 N and Al 12 N cluster is found particularly stable among the Al n N clusters.


2020 ◽  
Vol 49 (13) ◽  
pp. 4114-4124 ◽  
Author(s):  
Arghya Pratim Ghosh ◽  
Piotr Lodowski ◽  
Aida Bazarganpour ◽  
Marzena Leks ◽  
Pawel M. Kozlowski

Photolysis of methylcobalamin (MeCbl) in the presence of molecular oxygen (O2) has been investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT).


2020 ◽  
Vol 12 (7) ◽  
pp. 930-938
Author(s):  
D. K. Pandey ◽  
P. S. Yadav

An ab initio study has been performed for the stability, structural and electronic properties of forty-four ZnxTey (x + y = p = 2 to 5) nanoclusters by employing B3LYP-DFT/LANL2DZ method. The zero-point energy correction is also considered in this study. For a particular configuration, the nanoclusters containing a large number of Te atoms are found the most stable structure in comparison with the other nanoclusters. The most stable nanoclusters have either linear or planer structures and, only Zn4Te configuration has no stable structure as the structures of this configuration have at least one imaginary vibrational frequency. The HOMO–LUMO gap of the most stable structure shows a zigzag variation with the increase in the number of atoms in the nanocluster. The observed enhancement trend of the HOMO–LUMO gap with a decrease in the size of the nanocluster confirms to the quantum-confinement effect. The ionization potential (IP) shows decreasing behavior with an increase in the number of atoms in nanoclusters and the variation of electron affinity (EA) with nanocluster size shows zig-zag behavior.


2012 ◽  
Vol 86 (3) ◽  
Author(s):  
T. Nowozin ◽  
A. Marent ◽  
L. Bonato ◽  
A. Schliwa ◽  
D. Bimberg ◽  
...  

2019 ◽  
Vol 16 (31) ◽  
pp. 301-307
Author(s):  
Vanessa Mendes MATTJE ◽  
André Rodrigues PINHEIRO ◽  
Douglas Henrique PEREIRA

The present work made a molecular theoretical study of the structural and electronic properties of the geometric isomers of magnesium diboride (MgB2). The systems have specific characteristics and are very promising for technological applications, such as magnetic resonance imaging devices, motors, and generators. The same is still used in the industries of electronic devices, floating trains (MAGLEV), electricity and Biomagnetism. The results show that the geometric isomer with the lowest energy value is the cyclic species, which is the most stable. The formation enthalpies found were 205.38 Kcal mol-1 and 45.66 Kcal mol-1 for MgB2-cyclic and for B-Mg-B respectively. By means of the analysis Frontier Molecular Orbital it was possible to identify the shape of the HOMO - LUMO orbitals and how they contribute to the ligand and anti-ligand bands and thus to the superconducting properties of the compound. Finally, the NBO analysis confirmed that the most stable geometric isomer is MgB2-cyclic, presenting more interactions between donor or receptor orbitals.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1596 ◽  
Author(s):  
Jialin Yan ◽  
Jingjing Xia ◽  
Qinfang Zhang ◽  
Binwen Zhang ◽  
Baolin Wang

Based on the genetic algorithm (GA) incorporated with density functional theory (DFT) calculations, the structural and electronic properties of neutral and charged arsenic clusters Asn (n = 2–24) are investigated. The size-dependent physical properties of neutral clusters, such as the binding energy, HOMO-LUMO gap, and second difference of cluster energies, are discussed. The supercluster structures based on the As8 unit and As2 bridge are found to be dominant for the larger cluster Asn (n ≥ 8). Furthermore, the possible geometric structures of As28, As38, and As180 are predicted based on the growth pattern.


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