End-Group Influence on Frontier Molecular Orbital Reorganization and Thermoelectric Properties of Molecular Junctions

2013 ◽  
Vol 4 (22) ◽  
pp. 3825-3833 ◽  
Author(s):  
Janakiraman Balachandran ◽  
Pramod Reddy ◽  
Barry D. Dunietz ◽  
Vikram Gavini
Author(s):  
YAMIN WU ◽  
BIN LIAO ◽  
GUOLIANG WANG ◽  
BAOAN Bian

The effect of asymmetric lateral linking groups on the electronic transport is investigated in the biphenyl molecule-based device with gold electrodes with the framework of density functional theory and nonequilibrium Green’s function. The asymmetric lateral linking groups reduce the currents of molecular junctions, and result in the reverse rectifying behavior. The devices with asymmetric lateral linking groups –SH and –SCH3 have maximum rectifying ratios, while the asymmetric lateral linking group –SH and –NH2 cause minimum rectifying ratios. The calculated results suggest that the asymmetric lateral linking group induces the reduced coupling between molecule and right electrode, asymmetric distribution of frontier molecular orbital and asymmetric evolution of the molecular orbital eigenenergies, accounting for the rectifying behavior.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1708
Author(s):  
Ruochen Peng ◽  
Qu Zhou ◽  
Wen Zeng

As an insulating medium, sulfur hexafluoride (SF6) is extensively applied to electrical insulation equipment to ensure its normal operation. However, both partial discharge and overheating may cause SF6 to decompose, and then the insulation strength of electrical equipment will be reduced. The adsorption properties and sensing mechanisms of four SF6 decomposed components (HF, SO2, SOF2 and SO2F2) upon an Au-modified InN (Au-InN) monolayer were studied in this work based on first-principles theory. Meanwhile, the adsorption energy (Ead), charge transfer (QT), deformation charge density (DCD), density of states (DOS), frontier molecular orbital and recovery property were calculated. It can be observed that the structures of the SO2, SOF2 and SO2F2 molecules changed significantly after being adsorbed. Meanwhile, the Ead and QT of these three adsorption systems are relatively large, while that of the HF adsorption system is the opposite. These phenomena indicate that Au-InN monolayer has strong adsorption capacity for SO2, SOF2 and SO2F2, and the adsorption can be identified as chemisorption. In addition, through the analysis of frontier molecular orbital, it is found that the conductivity of Au-InN changed significantly after adsorbing SO2, SOF2 and SO2F2. Combined with the analysis of the recovery properties, since the recovery time of SO2 and SO2F2 removal from Au-InN monolayer is still very long at 418 K, Au-InN is more suitable as a scavenger for these two gases rather than as a gas sensor. Since the recovery time of the SOF2 adsorption system is short at 418 K, and the conductivity of the system before and after adsorption changes significantly, Au-InN is an ideal SOF2 gas-sensing material. These results show that Au-InN has broad application prospects as an SO2, SOF2 and SO2F2 scavenger and as a resistive SOF2 sensor, which is of extraordinary meaning to ensure the safe operation of power systems. Our calculations can offer a theoretical basis for further exploration of gas adsorbent and resistive sensors prepared by Au-InN.


2021 ◽  
Vol 27 (6) ◽  
Author(s):  
Shanshan Tang ◽  
Qinghua Zhou ◽  
Xiaoli Lv ◽  
Dadong Liang ◽  
Ruifa Jin ◽  
...  

2015 ◽  
Vol 80 (8) ◽  
pp. 997-1008 ◽  
Author(s):  
Maryam Dehestani ◽  
Leila Zeidabadinejad

Topological analyses of the electron density using the quantum theory of atoms in molecules (QTAIM) have been carried out at the B3PW91/6-31g (d) theoretical level, on bis(pyrazol-1-yl)methanes derivatives 9-(4-(di (1H-pyrazol-1-yl)-methyl)phenyl)-9H-carbazole (L) and its zinc(II) complexes: ZnLCl2 (1), ZnLBr2 (2) and ZnLI2 (3). The topological parameters derived from Bader theory were also analyzed; these are characteristics of Zn-bond critical points and also of ring critical points. The calculated structural parameters are the frontier molecular orbital energies highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), hardness (?), softness (S), the absolute electronegativity (?), the electrophilicity index (?) and the fractions of electrons transferred (?N) from ZnLX2 complexes to L. The numerous correlations and dependencies between energy terms of the Symmetry Adapted Perturbation Theory approach (SAPT), geometrical, topological and energetic parameters were detected and described.


Author(s):  
Xue Li ◽  
Changsheng Shi ◽  
Yuhang Mo ◽  
Jiancheng Rao ◽  
Lei Zhao ◽  
...  

Frontier molecular orbital engineering has been demonstrated to achieve aggregation induced delayed fluorescence (AIDF) for non-doped OLEDs. As a proof of concept, a new model compound AT-spiro-DMACF is reported on...


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