scholarly journals Theoretical Study of the Effect of π-Bridge on Optical and Electronic Properties of Carbazole-Based Sensitizers for DSSCs

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3670
Author(s):  
Tomás Delgado-Montiel ◽  
Jesús Baldenebro-López ◽  
Rody Soto-Rojo ◽  
Daniel Glossman-Mitnik

Eight novel metal-free organic sensitizers were proposed for dye-sensitized solar cells (DSSCs), theoretically calculated and studied via density functional theory with D-π-A structure. These proposals were formed to study the effect of novel π-bridges, using carbazole as the donor group and cyanoacrylic acid as the anchorage group. Through the M06/6-31G(d) level of theory, ground state geometry optimization, vibrational frequencies, the highest occupied molecular orbital, the lowest unoccupied molecular orbital, and their energy levels were calculated. Further, chemical reactivity parameters were obtained and analyzed, such as chemical hardness (η), electrophilicity index (ω), electroaccepting power (ω+) and electrodonating power (ω-). Free energy of electron injection (ΔGinj) and light-harvesting efficiency (LHE) also were calculated and discussed. On the other hand, absorption wavelengths, oscillator strengths, and electron transitions were calculated through time-dependent density functional theory with the M06-2X/6-31G(d) level of theory. In conclusion, the inclusion of thiophene groups and the Si heteroatom in the π-bridge improved charge transfer, chemical stability, and other optoelectronic properties of carbazole-based dyes.

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4043 ◽  
Author(s):  
Temiloluwa T. Adejumo ◽  
Nikolaos V. Tzouras ◽  
Leandros P. Zorba ◽  
Dušanka Radanović ◽  
Andrej Pevec ◽  
...  

Two new Zn(II) complexes with tridentate hydrazone-based ligands (condensation products of 2-acetylthiazole) were synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction methods. The complexes 1, 2 and recently synthesized [ZnL3(NCS)2] (L3 = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium) complex 3 were tested as potential catalysts for the ketone-amine-alkyne (KA2) coupling reaction. The gas-phase geometry optimization of newly synthesized and characterized Zn(II) complexes has been computed at the density functional theory (DFT)/B3LYP/6–31G level of theory, while the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO and LUMO) energies were calculated within the time-dependent density functional theory (TD-DFT) at B3LYP/6-31G and B3LYP/6-311G(d,p) levels of theory. From the energies of frontier molecular orbitals (HOMO–LUMO), the reactivity descriptors, such as chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and electrophilicity index (ω) have been calculated. The energetic behavior of the investigated compounds (1 and 2) has been examined in gas phase and solvent media using the polarizable continuum model. For comparison reasons, the same calculations have been performed for recently synthesized [ZnL3(NCS)2] complex 3. DFT results show that compound 1 has the smaller frontier orbital gap so, it is more polarizable and is associated with a higher chemical reactivity, low kinetic stability and is termed as soft molecule.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ahmad Irfan ◽  
Abdullah G. Al-Sehemi ◽  
Shabbir Muhammad

Geometries, electronic properties, and absorption spectra of the dyes which are a combination of thiophene based dye (THPD) and IR dyes (covering IR region; TIRBD1-TIRBD3) were performed using density functional theory (DFT) and time dependent density functional theory (TD-DFT), respectively. Different electron donating groups, electron withdrawing groups, and IR dyes have been substituted on THPD to enhance the efficiency. The bond lengths of new designed dyes are almost the same. The lowest unoccupied molecular orbital energies of designed dyes are above the conduction band of TiO2 and the highest occupied molecular orbital energies are below the redox couple revealing that TIRBD1-TIRBD3 would be better sensitizers for dye-sensitized solar cells. The broad spectra and low energy gap also showed that designed materials would be efficient sensitizers.


2017 ◽  
Vol 70 (3) ◽  
pp. 328 ◽  
Author(s):  
Sarvesh Kumar Pandey ◽  
Mohammad Faheem Khan ◽  
Shikha Awasthi ◽  
Reetu Sangwan ◽  
Sudha Jain

The topological features of the charge densities, ρ(r), and the chemical reactivity of two most biologically relevant and chemically interesting scaffold systems i.e. trans-communic acid and imbricatolic acid have been determined using density functional theory. To identify, characterize, and quantify efficiently, the non-covalent interactions of the atoms in the molecules have been investigated quantitatively using Bader's quantum theory of atoms-in-molecules (QTAIM) technique. The bond path is shown to persist for a range of weak H···H as well as C···H internuclear distances (in the range of 2.0–3.0 Å). These interactions exhibit all the hallmarks of a closed-shell weak interaction. To get insights into both systems, chemical reactivity descriptors, such as HOMO–LUMO, ionization potential, and chemical hardness, have been calculated and used to probe the relative stability and chemical reactivity. Some other useful information is also obtained with the help of several other electronic parameters, which are closely related to the chemical reactivity and reaction paths of the products investigated. Trans-communic acid seems to be chemically more sensitive when compared with imbricatolic acid due to its experimentally observed higher half-maximal inhibitory concentration (bioactivity parameter) value, which is in accordance with its higher chemical reactivity as theoretically predicted using density functional theory-based reactivity index. The quantum chemical calculations have also been performed in solution using different solvents, and the relative order of their structural and electronic properties as well as QTAIM-based parameters show patterns similar to those observed in gas phase only. This study further exemplifies the use and successful application of the bond path concept and the quantum theory of atoms-in-molecules.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Umer Mehmood ◽  
Ibnelwaleed A. Hussein ◽  
Khalil Harrabi ◽  
Shakeel Ahmed

The molecular structures and UV-visible absorption spectra of complex photosensitizers comprising oxadiazole isomers as theπ-bridges were analyzed by density functional theory (DFT) and time-dependent DFT. The ground state and excited state oxidation potentials, HOMOs and LUMOs energy levels, and electron injection from the dyes to semiconductor TiO2have been computed in vacuum here. The results show that all of the dyes may potentially be good photosensitizers in DSSC. To justify the simulation basis, N3 dye was also simulated under the similar conditions. Simulated absorption spectrum, HOMO, LUMO, and band gap values of N3 were compared with the experimental values. We also computed the electronic structure properties and absorption spectra of dye/(TiO2)8systems to elucidate the electron injection efficiency at the interface. This work is expected to give proper orientation for experimental synthesis.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Rody Soto-Rojo ◽  
Jesús Baldenebro-López ◽  
Daniel Glossman-Mitnik

Eight coumarin derivative dyes were studied by varying theπ-bridge size with different thiophene and thiazole units for their potential use in dye-sensitized solar cells (DSSC). Geometry optimization, the energy levels and electron density of the Highest Occupied Molecular Orbital and the Lowest Unoccupied Molecular Orbital, and ultraviolet-visible absorption spectra were calculated by Density Functional Theory (DFT) and Time-Dependent-DFT. All molecular properties were analyzed to decide which dye was the most efficient. Furthermore, chemical reactivity parameters, such as chemical hardness, electrophilicity index, and electroaccepting power, were obtained and analyzed, whose values predicted the properties of the dyes in addition to the rest of the studied molecular properties. Our calculations allow us to qualitatively study dye molecules and choose the best for use in a DSSC. The effects ofπ-bridges based on thiophenes, thiazoles, and combinations of the two were reviewed; dyes with three units mainly of thiazole were chosen as the best photosensitizers for DSSC.


2020 ◽  
Vol 21 (4) ◽  
pp. 1253 ◽  
Author(s):  
Mohamed E. Elshakre ◽  
Mahmoud A. Noamaan ◽  
Hussein Moustafa ◽  
Haider Butt

In this work, three computational methods (Hatree-Fock (HF), Møller–Plesset 2 (MP2), and Density Functional Theory (DFT)) using a variety of basis sets are used to determine the atomic and molecular properties of dihydrothiouracil-based indenopyridopyrimidine (TUDHIPP) derivatives. Reactivity descriptors of this system, including chemical potential (µ), chemical hardness (η), electrophilicity (ω), condensed Fukui function and dual descriptors are calculated at B3LYP/6-311++ G (d,p) to identify reactivity changes of these molecules in both gas and aqueous phases. We determined the molecular electrostatic surface potential (MESP) to determine the most active site in these molecules. Molecular docking study of TUDHIPP with topoisomerase II α and β is performed, predicting binding sites and binding energies with amino acids of both proteins. Docking studies of TUDHIPP versus etoposide suggest their potential as antitumor candidates. We have applied Lipinski, Veber’s rules and analysis of the Golden triangle and structure activity/property relationship for a series of TUDHIPP derivatives indicate that the proposed compounds exhibit good oral bioavailability. The comparison of the drug likeness descriptors of TUDHIPP with those of etoposide, which is known to be an antitumor drug, indicates that TUDHIPP can be considered as an antitumor drug. The overall study indicates that TUDHIPP has comparable and even better descriptors than etoposide proposing that it can be as effective antitumor drug, especially 2H, 6H and 7H compounds.


Computation ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 52 ◽  
Author(s):  
Norma Flores-Holguín ◽  
Juan Frau ◽  
Daniel Glossman-Mitnik

A methodology based on concepts that arose from Density Functional Theory (CDFT) was chosen for the calculation of global and local reactivity descriptors of the Seragamide family of marine anticancer peptides. Determination of active sites for the molecules was achieved by resorting to some descriptors within Molecular Electron Density Theory (MEDT) such as Fukui functions. The pKas of the six studied peptides were established using a proposed relationship between this property and calculated chemical hardness. The drug likenesses and bioactivity properties of the peptides considered in this study were obtained by resorting to a homology model by comparison with the bioactivity of related molecules in their interaction with different receptors. With the object of analyzing the concept of drug repurposing, a study of potential AGE-inhibition abilities of Seragamides peptides was pursued by comparison with well-known drugs that are already available as pharmaceuticals.


Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 914 ◽  
Author(s):  
Md Al Mamunur Rashid ◽  
Dini Hayati ◽  
Kyungwon Kwak ◽  
Jongin Hong

Two donor-π-spacer-acceptor (D-π-A) organic dyes were designed as photochromic dyes with the same π-spacer and acceptor but different donors, based on their electron-donating strength. Various structural, electronic, and optical properties, chemical reactivity parameters, and certain crucial factors that affect short-circuit current density (Jsc) and open circuit voltage (Voc) were investigated computationally using density functional theory and time-dependent density functional theory. The trans-cis isomerization of these azobenzene-based dyes and its effect on their properties was studied in detail. Furthermore, the dye-(TiO2)9 anatase nanoparticle system was simulated to understand the electronic structure of the interface. Based on the results, we justified how the trans-cis isomerization and different donor groups influence the physical properties as well as the photovoltaic performance of the resultant dye-sensitized solar cells (DSSCs). These theoretical calculations can be used for the rapid screening of promising dyes and their optimization for photochromic DSSCs.


2021 ◽  
Vol 03 (02) ◽  
pp. 18-27
Author(s):  
Methaq Talib MATROOD ◽  
Aqeel Adil HASAN

Nanomedicine remains the medicinalrequest of nanotechnology. Nanodrugvarietiesafter the medicinalrequests of nanoparticles, to nanoelectronic biosensors, thenuniform possible future applications of particle nanotechnology.Nanoparticle of medicationtransporters are optimized aimed atpreoccupation of medicationsfinishedbreathtreatment. Demonstrating and imitation of nanocrystal limits of the theophylline (C7H8N4O2)byindium – antimony (In7Sb7H20 (in diamantane constructionhave been performed by Gaussian 09 program. DFT hasremainedused for InSb nanoparticle, theophyllinemedication. Optimization and frequency on the ground national level,PBEPBE, 3-21G basis sets consumesremainedexamined. The custodiesaimed ataltogetherremainequivalenttoward zero custodies. The geometry optimization by means of both methods (PBE) for InSb diamantane nanoparticles and theophyllinedrug has been originate cutting-edgedecent agreement by experimental dataMolecular detour theory has been used to discovery highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies. Total energy, ionization potential and electron empathy have beenintendedaimed atInSbnanostructure bytheophyllinemedication.


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