scholarly journals Effect of Nitrogen Cation as “Electron Trap” at π-Linker on Properties for p-Type Photosensitizers: DFT Study

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3134 ◽  
Author(s):  
Zhi-Dan Sun ◽  
Jiang-Shan Zhao ◽  
Xue-Hai Ju ◽  
Qi-Ying Xia
Keyword(s):  
Driving Force ◽  
Density Functional ◽  
Electron Trap ◽  
Hole Injection ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Td Dft ◽  
Harvesting Efficiency ◽  
Light Harvesting Efficiency ◽  
P Type

On the basis of thieno(3,2-b)thiophene and dithieno[3,2-b:2′,3′-d]thiophene (T2 and T3 moieties) as π-linker, the A, D and S series dyes were designed to investigate the effect of the introducing N+ as an “electron trap” into T2 and T3 on the properties of the dyes. The optimized structures, electronic and optical properties were investigated by the density functional theory (DFT) and time-dependent DFT (TD-DFT). The results show that the properties of the dyes are sensitive to the N+ position in π-linkers. D series dyes with electron-withdrawing units located near the donor have better properties than the corresponding A series with the electron-withdrawing units located near the acceptor. For A and D series, the N+ modified dye named T2N+1-d displays the largest red shift of the UV–vis absorption, the maximum integral values of the adsorption-wavelength curves over the visible light, the highest light harvesting efficiency (LHE, 0.996), and the strongest adsorption energy (−44.33 kcal/mol). T2N+1-d also has a large driving force of hole injection (ΔGinj, −0.74 eV), which results in a more efficient hole injection. Bearing a lengthier π-linker than T2N+1-d, the properties of T2N+1-s are further improved. T2N+1-d moiety or its increased conjugated derivatives may be a promising π-linker.

scholarly journals Strain Effects on the Electronic and Thermoelectric Properties of n(PbTe)-m(Bi2Te3) System Compounds

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4086
Author(s):  
Weiliang Ma ◽  
Marie-Christine Record ◽  
Jing Tian ◽  
Pascal Boulet
Keyword(s):  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Compressive Strain ◽  
Van Der Waals Interactions ◽  
Functional Theory ◽  
Band Engineering ◽  
Seebeck Coefficients ◽  
The Density Functional Theory ◽  
P Type ◽  
Narrow Band Gap Semiconductors

Owing to their low lattice thermal conductivity, many compounds of the n(PbTe)-m(Bi2Te3) homologous series have been reported in the literature with thermoelectric (TE) properties that still need improvement. For this purpose, in this work, we have implemented the band engineering approach by applying biaxial tensile and compressive strains using the density functional theory (DFT) on various compounds of this series, namely Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5. All the fully relaxed Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5 compounds are narrow band-gap semiconductors. When applying strains, a semiconductor-to-metal transition occurs for all the compounds. Within the range of open-gap, the electrical conductivity decreases as the compressive strain increases. We also found that compressive strains cause larger Seebeck coefficients than tensile ones, with the maximum Seebeck coefficient being located at −2%, −6%, −3% and 0% strain for p-type Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5, respectively. The use of the quantum theory of atoms in molecules (QTAIM) as a complementary tool has shown that the van der Waals interactions located between the structure slabs evolve with strains as well as the topological properties of Bi2Te3 and PbBi2Te4. This study shows that the TE performance of the n(PbTe)-m(Bi2Te3) compounds is modified under strains.

scholarly journals Enhancing the Light Harvesting Efficiency, Open Circuit Voltage And Stability of Molybdenum Doped (Zno)6 Nanocluster in Dye-Sensitized Solar Cells: A DFT Study

2018 ◽  
Vol 34 (5) ◽  
pp. 2292-2304
Author(s):  
S. Dheivamalar ◽  
K. Bansura banu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Open Circuit Voltage ◽  
Dye Sensitized Solar Cells ◽  
Open Circuit ◽  
Functional Theory ◽  
Dye Sensitized ◽  
Harvesting Efficiency ◽  
Light Harvesting Efficiency ◽  
Sensitized Solar Cells

In this study, the electronic and structural properties of drum structured Mo-doped Zn6O6 (MoZn5O6) cluster as the π conjugated bridging in the dye-sensitized solar cells (DSSC) were compared with its pristine form by density functional theory (DFT) calculations under Gaussian 09 Program. The frontier molecular orbital study was explored to determine the charge transport characteristics of donor-acceptor moieties over the entire visible range and the electron injection from the valence band (LUMO) orbital to the conduction band (HOMO) orbital of MoZn5O6. The energy gap (Eg), binding energy (EB), global reactivity descriptors, thermodynamic parameters and the dipole moment were also calculated for MoZn5O6 and compared with Zn6O6. The density of states (DOS) of MoZn5O6 material was investigated to demonstrate the importance of d orbital of Mo atom in hybridization. To examine the charge distribution, Mulliken atomic charge distribution and molecular electrostatic potential (MEP) were analyzed. A spectroscopic study was included for the better perception of the interaction of Mo with Zn6O6 cluster. The increased value of the first-order hyperpolarizability of MoZn5O6 from its pure clustermanifests the MoZn5O6 is a better candidate with the superior nonlinear optical property. The analysis of UV-Vis spectra through the time-dependent density functional theory (TD-DFT) discovers that the MoZn5O6 has larger light harvesting efficiency (LHE) which influences the higher photon to current conversion efficiency. As a result, the valence band (LUMO) of MoZn5O6 is intense than the conduction band (HOMO) of MoZn5O6 making an increase in the open circuit voltage (VOC) and hence it confirms that the MoZn5O6 material can be a used in photovoltaic applications.

A theoretical investigation on promising acceptor groups for POM-based dyes: from electronic structure to photovoltaic conversion efficiency

2020 ◽  
Vol 8 (1) ◽  
pp. 219-227 ◽  
Author(s):  
Yu Gao ◽  
Wei Guan ◽  
Li-Kai Yan ◽  
Zhong-Min Su
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Photovoltaic Conversion Efficiency ◽  
Acceptor Group ◽  
The Density Functional Theory ◽  
Td Dft

Theoretical calculations based on the density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to screen efficient acceptor group candidates for POM-based dyes.

scholarly journals Prediction for electronic, vibrational and thermoelectric properties of chalcopyrite AgX(X=In,Ga)Te 2 : PBE + U approach

2017 ◽  
Vol 4 (10) ◽  
pp. 170750 ◽  
Author(s):  
Jianhui Yang ◽  
Qiang Fan ◽  
Xinlu Cheng
Keyword(s):  
Density Functional ◽  
Functional Results ◽  
Chalcopyrite Structure ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Thermoelectric Transport ◽  
The Density Functional Theory ◽  
Wide Range ◽  
Thermoelectric Transport Properties ◽  
P Type

The electronic, vibrational and thermoelectric transport characteristics of AgInTe 2 and AgGaTe 2 with chalcopyrite structure have been investigated. The electronic structures are calculated using the density-functional theory within the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof functional considering the Hubbard-U exchange correlation. The band-gaps of AgInTe 2 and AgGaTe 2 are much larger than previous standard GGA functional results and agree well with the existing experimental data. The effective mass of the hole and the shape of density of states near the edge of the valence band indicate AgInTe 2 and AgGaTe 2 are considerable p-type thermoelectric materials. An analysis of lattice dynamics shows the low thermal conductivities of AgInTe 2 and AgGaTe 2 . The thermoelectric transport properties' dependence on carrier concentration for p-type AgInTe 2 and AgGaTe 2 in a wide range of temperatures has been studied in detail. The results show that p-type AgInTe 2 and AgGaTe 2 at 800 K can achieve the merit values of 0.91 and 1.38 at about 2.12 × 10 20  cm −3 and 1.97 × 10 20  cm −3 carrier concentrations, respectively. This indicates p-type AgGaTe 2 is a potential thermoelectric material at high temperature.

The mechanical, optical and thermoelectric properties of MCoF3 (M = K and Rb) compounds

2017 ◽  
Vol 31 (06) ◽  
pp. 1750033 ◽  
Author(s):  
A. A. Mubarak
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Full Potential ◽  
Functional Theory ◽  
Half Metallic ◽  
Augmented Plane Wave ◽  
The Density Functional Theory ◽  
Type Character ◽  
P Type ◽  
Linearized Augmented Plane Wave

This is an ab initio study instituted on the density functional theory (DFT) and the full-potential linearized augmented plane wave (FP-LAPW) calculations that are performed to analyze the mechanical, electronic, optical and thermoelectric properties of the cubic MCoF3 compound (M = K and Rb). The studied compounds are found thermodynamically and mechanically stable. Moreover, these compounds are found to be elastically anisotropic and ductile. KCoF3 and RbCoF3 are classified as half-metallic and anti-ferromagnetic compounds. The optical properties are investigated from the dielectric function for the different energy ranges. The thermoelectric properties such as transport properties are determined as a function of temperature using BoltzTrape code in the range of 20–800 K. The present compounds are found to have p-type character. Also, the majority charge carriers are found to be electrons rather than hole. Useful mechanical, spintronic, optical and thermoelectric applications are predicted based upon the calculations.

scholarly journals Quantum Chemical Investigation on D-π-A Based Phenothiazine Organic Chromophores with Spacer and Electron Acceptor Effect for DSSCs

2021 ◽  
Author(s):  
Anbarasan Ponnusamy Munusamy ◽  
Arunkumar Ammasi ◽  
Shanavas Shajahan ◽  
Tansir Ahamad
Keyword(s):  
Electron Acceptor ◽  
Density Functional ◽  
Organic Dyes ◽  
Dye Sensitized Solar Cells ◽  
Functional Theory ◽  
Organic Chromophores ◽  
Efficient Performance ◽  
The Density Functional Theory ◽  
Td Dft ◽  
Sensitized Solar Cells

Abstract In this work, the newly designed phenothiazine based organic dye (PT-BTBA, PT-EBTBA and PT-EBTEBA) derivatives were screened and investigated for dye-sensitized solar cells (DSSCs) application. The literature dye of SB covers the electron-donor (D) in phenothiazine and cyanoacrylic acid in electron-acceptor (A) based on D-A structure. In order to improving the π-conjugation and acceptor effects on the SB dye were investigated. The effect of D-π-A designed dyes on the optical absorption spectra and photovoltaic (PV) parameters were implemented by the density functional theory (DFT) and time‐dependent DFT (TD-DFT) calculations. Also, the hybrid functionals were initially evaluated to establish an accurate methodology for calculating the first-singlet absorption peak of SB dye. Consequently, TD-CAM-B3LYP functional and 6-311++G(d,p) theory were well match with the literature data. According to this result, phenothiazine-4-((7-ethynylbenzo[c][1,2,5]thiadiazol-4-yl)ethynyl)benzoic acid (PT-EBTEBA) dye has the strong group for more red-shifted and successfully electron inject into TiO2 surface. It is expected to provide some theoretical guidance on designing photosensitive with new metal-free organic dyes for use in DSSCs yielding highly efficient performance.

scholarly journals Theoretical modeling of optical spectra of N(1) and N(10) substituted lumichrome derivatives

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Denisa Cagardová ◽  
Jan Truksa ◽  
Martin Michalík ◽  
Jan Richtár ◽  
Jozef Krajčovič ◽  
...  
Keyword(s):  
Density Functional ◽  
Optical Transition ◽  
Photophysical Properties ◽  
Energy Levels ◽  
Dft Method ◽  
Functional Theory ◽  
Transition Energies ◽  
The Density Functional Theory ◽  
Td Dft

AbstractA systematic study of (7,8-dimethylated) alloxazine, isoalloxazine, and their derivatives with substituted N(1) and N(10) positions was conducted using the density functional theory. The main aim of this work was the direct investigation of substituent effect on the molecular structure. Furthermore, HOMED aromaticity indices were calculated to describe the scope of the geometry changes. Frontier molecular orbitals of reference alloxazine, isoalloxazine and lumichrome derivatives were discussed by means of changes in their shape and energy levels. Photophysical properties were analyzed by determination of optical transition energies using the TD-DFT method. Obtained results were compared with previously published experimental data.

Conformational, vibrational and electronic properties of CH3(CH2)3CX2NH2 (X = H, F, Cl or Br): Halogen and solvent effects

2015 ◽  
Vol 14 (04) ◽  
pp. 1550031
Author(s):  
Cemal Parlak ◽  
Münevver Gökce ◽  
Mahir Tursun ◽  
Lydia Rhyman ◽  
Ponnadurai Ramasami
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Basis Set ◽  
Chemical Hardness ◽  
Uv Spectrum ◽  
Dft Methods ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Td Dft

The effects of varying halogen and solvent, in terms of vibrational and electronic properties, on the different conformers of 1-pentanamine [ CH 3( CH 2)4 NH 2] and 1,1-dihalogeno-pentan-1-amines [ CH 3( CH 2)3 CX 2 NH 2; X = F , Cl or Br ] were investigated by employing the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The B3LYP functional was used with the 6-31++G(d,p) basis set. Computations were focused on the 10 conformational isomers of the compounds in the gas phase and both in non-polar (benzene) and polar (methanol) solvents. The present work explores the effects of the halogen and the medium on the conformational preference, and geometrical parameter, dipole moment, NH 2 vibrational frequency, UV spectrum, highest occupied and lowest unoccupied molecular orbitals (HOMO–LUMO) orbital and DOS diagram of the conformers. The atypical characteristics of fluorine and bromine affecting the electrical bandgap, chemical hardness, electronegativity, PDOS or OPDOS plots and the absorption band are observed correspondingly. The findings of this work can be useful to those systems involving changes in the conformations analogous to the compounds studied.

scholarly journals Computational Insights on the Mechanism of the Chemiluminescence Reaction of New Group of Chemiluminogens—10-Methyl-9-thiophenoxycarbonylacridinium Cations

2020 ◽  
Vol 21 (12) ◽  
pp. 4417
Author(s):  
Milena Pieńkos ◽  
Beata Zadykowicz
Keyword(s):  
Quantum Yield ◽  
Density Functional ◽  
Single Atom ◽  
Human Organism ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Aqueous Environments ◽  
Td Dft ◽  
Electronically Excited ◽  
Potential Applicability

Immunodiagnostics, in which one of the promising procedures is the chemiluminescent labelling, is essential to facilitate the detection of infections in a human organism. One of the standards commonly used in luminometric assays is luminol, which characterized by low quantum yield in aqueous environments. Acridinium esters have better characteristics in this topic. Therefore, the search for new derivatives, especially those characterized by the higher quantum yield of chemiluminescence, is one of the aims of the research undertaken. Using the proposed mechanism of chemiluminescence, we examined the effect of replacing a single atom within a center of reaction on the efficient transformation of substrates into electronically excited products. The density functional theory (DFT) and time dependent (TD) DFT calculated thermodynamic and kinetic data concerning the chemiluminescence and competitive dark pathways suggests that some of the scrutinized derivatives have better characteristics than the chemiluminogens used so far. Synthesis of these candidates for efficient chemiluminogens, followed by studies of their chemiluminescent properties, and ultimately in chemiluminescent labelling, are further steps to confirm their potential applicability in immunodiagnostics.

Sign in / Sign up

Export Citation Format

Share Document