scholarly journals UV–Vis Absorption Properties of New Aromatic Imines and Their Compositions with Poly({4,8-bis[(2-Ethylhexyl)oxy]Benzo[1,2-b:4,5-b′]Dithiophene-2,6-diyl}{3-Fluoro-2-[(2-Ethylhexyl)Carbonyl]Thieno[3,4-b]Thiophenediyl})

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4191 ◽  
Author(s):  
Agnieszka Gonciarz ◽  
Robert Pich ◽  
Krzysztof Artur Bogdanowicz ◽  
Beata Jewloszewicz ◽  
Wojciech Przybył ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Bulk Heterojunction ◽  
Theoretical Calculations ◽  
Dft Methods ◽  
Functional Theory ◽  
Chemical Structures ◽  
Vis Spectroscopy ◽  
Aromatic Imines

In this paper, four new aromatic imines containing at least one thiazole-based heterocycle were analyzed in detail by UV–Vis spectroscopy, taking into consideration their chemical structures and interactions with PTB7, a known polymeric electron donor widely used in bulk heterojunction organic solar cells. It is demonstrated that the absorption spectra of the investigated active compositions can be modified not only by changing the chemical structure of imine, but also via formulations with PTB7. For all investigated imines and PTB7:imine compositions, calibration curves were obtained in order to find the optimum concentration in the composition with PTB7 for expansion and optimization of absorption spectra. All imines and PTB7:imine compositions were investigated in 1,2-dichlorobenzene by UV–Vis spectroscopy in various concentrations, monitoring the changes in the π–π* and n–π* transitions. With increasing imine concentrations, we did not observe changes in absorption maxima, while with increasing imine concentrations, a hypochromic effect was observed. Finally, we could conclude that all investigated compositions exhibited wide absorptions of up to 800 nm and isosbestic points in the range of 440–540 nm, confirming changes in the macromolecular organization of the tested compounds. The theoretical calculations of their vibration spectra (FTIR) and LUMO–HOMO levels by Density Functional Theory (DFT) methods are also provided. Finally, IR thermal images were measured for organic devices based on imines and the imine:PTB7 composite.

scholarly journals 1,3,4-Thiadiazole-Containing Azo Dyes: Synthesis, Spectroscopic Properties and Molecular Structure

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2822
Author(s):  
Agnieszka Kudelko ◽  
Monika Olesiejuk ◽  
Marcin Luczynski ◽  
Marcin Swiatkowski ◽  
Tomasz Sieranski ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Properties ◽  
Radiation Absorption ◽  
Functional Theory ◽  
Chemical Structures ◽  
Vis Spectroscopy ◽  
High Yields

Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by 1H-NMR, 13C-NMR, IR, UV-Vis spectroscopy, mass spectrometry and elemental analysis. In addition, the X-ray single crystal structure of a representative azo dye was presented. For explicit determination of the influence of a substituent on radiation absorption in UV-Vis range, time-dependent density functional theory calculations were performed.

scholarly journals Charge-sensitive vibrational modes in the (EDT-TTF-OX)2AsF6 chiral molecular conductors

Open Physics ◽  
2014 ◽  
Vol 12 (3) ◽  
Author(s):  
Iwona Olejniczak ◽  
Arkadiusz Frąckowiak ◽  
Jacek Matysiak ◽  
Augustin Madalan ◽  
Flavia Pop ◽  
...  
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Charge Ordering ◽  
Racemic Mixture ◽  
Vibrational Modes ◽  
Frequency Range ◽  
Donor Molecule ◽  
Dft Methods ◽  
Molecular Conductors ◽  
Functional Theory

AbstractInfrared and Raman spectra of three chiral molecular conductors (EDT-TTF-OX)2AsF6, comprising of two salts based on enantiopure EDT-TTF-OX donor molecules and one based on their racemic mixture, have been measured as a function of temperature. In the frequency range of the C=C stretching vibrations of EDT-TTF-OX, charge-sensitive modes are identified based on theoretical calculations for neutral and oxidized EDT-TTF-OX using density functional theory (DFT) methods. The positions of C=C stretching modes in both Raman and infrared spectra of the (EDT-TTF-OX)2AsF6 materials are analyzed assuming a linear relationship between the frequency and charge of the molecule. The charge density on the EDTTTF-OX donor molecule is estimated to be +0.5 in all investigated materials and does not change with temperature. Therefore we suggest, that M-I transition observed in (EDT-TTF-OX)2AsF6 chiral molecular conductors at low temperature is not related to the charge ordering mechanism.

N-Alkylthienopyrroledione versus benzothiadiazole pulling units in push–pull copolymers used for photovoltaic applications: density functional theory study

2016 ◽  
Vol 18 (2) ◽  
pp. 1017-1024 ◽  
Author(s):  
Jamin Ku ◽  
Yeongrok Gim ◽  
Yves Lansac ◽  
Yun Hee Jang
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Band Gap ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Bulk Heterojunction ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Low Band Gap ◽  
Photovoltaic Applications

Low-band-gap push–pull copolymers are promising donor materials for bulk heterojunction organic solar cells.

scholarly journals Diketopyrrolopyrrole based highly conjugated small molecules for organic solar cells

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Sana Akram ◽  
Azra Quraishi ◽  
Abid Hussain ◽  
Nadia Zulfiqar ◽  
Madiha Akbar
Keyword(s):  
Small Molecules ◽  
Organic Solar Cells ◽  
Organic Solar Cell ◽  
High Performance ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Td Dft ◽  
Optimization Of Geometry

A series of three donor molecules (DPP-B, DPP-N and DPP-P) based on diketopyrrolopyrrole (DPP) sharing the similar backbone of D-π-A-π-D have been investigated. In these molecules, substituents such as pyrene, naphthalene and benzene act as the electron donating end groups, DPP as the central core unit and thiophene has been used as a bridge between donor and acceptor fragments. Theoretical calculations have been carried out with the help of density functional theory (DFT) and time-dependent functional theory (TD-DFT). For the optimization of geometry of investigated molecules, DFT functional B3LYP/6-31g(d) has been used and TD-B3LYP/6-31g(d) has been used to obtain the best results of calculations inexcited state. DPP-P has been considered a suitable donor molecule among all investigated molecules as it manifests the suitable value of Eg of 2.24 eV and showed the stronger absorption λmaxof 611 nm. Hence, this study reveals that investigated donor molecules are suitable for high performance organic solar cell devices

scholarly journals Mechanism, kinetics and selectivity of selenocyclization of 5-alkenylhydantoins: an experimental and computational study

2015 ◽  
Vol 11 ◽  
pp. 1865-1875 ◽  
Author(s):  
Biljana M Šmit ◽  
Radoslav Z Pavlović ◽  
Dejan A Milenković ◽  
Zoran S Marković
Keyword(s):  
Density Functional Theory ◽  
Double Bond ◽  
Density Functional ◽  
Computational Study ◽  
Theoretical Calculations ◽  
Reaction Products ◽  
Dft Methods ◽  
Functional Theory ◽  
H Nmr ◽  
Good Agreement

The mechanism and selectivity of a bicyclic hydantoin formation by selenium-induced cyclization are investigated. The proposed mechanism involves the intermediates formed by an electrophilic addition of the selenium reagent on a double bond of the starting 5-alkenylhydantoin prior the cyclization. These intermediates are readily converted into the more stable cyclic seleniranium cations. A key step of the mechanism is an intramolecular cyclization which is realized through an anti-attack of the internal nucleophile, the amidic nitrogen, to the seleniranium cation yielding the intermediate imidazolinium cations. Their deprotonation is followed by the formation of the fused bicyclic reaction products. Important intermediates and key transition states are studied by using density functional theory (DFT) methods. The pathways of the reaction are investigated in detail. There are two regioselective pathways related to 5-exo and 6-endo products. Theoretical calculations and the monitoring of the cyclization reaction using 1H NMR spectroscopy are in a good agreement with the proposed mechanism and are consistent with our experimental results. The preferred pathway for formation of 5-exo products is confirmed.

Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

2018 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Athanassis Katsenis ◽  
Novendra Novendra ◽  
Zamirbek Akimbekov ◽  
Dayaker Gandrath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Experimental Evaluation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zeolitic Imidazolate Framework ◽  
Functional Theory ◽  
Calorimetric Measurements ◽  
And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

scholarly journals Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Wiebeler ◽  
Joachim Vollbrecht ◽  
Adam Neuba ◽  
Heinz-Siegfried Kitzerow ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Spectroscopic Properties ◽  
Absorption Bands ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Hartree Fock ◽  
Tauc Plot ◽  
Electrochemical Approach

AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

scholarly journals A machine learning platform for the discovery of materials

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Carl E. Belle ◽  
Vural Aksakalli ◽  
Salvy P. Russo
Keyword(s):  
Machine Learning ◽  
Density Functional ◽  
Gw Approximation ◽  
Dft Methods ◽  
Functional Theory ◽  
Unit Cell Size ◽  
Learning Platform ◽  
Photovoltaic Materials ◽  
Wide Range ◽  
Quantum Espresso

AbstractFor photovoltaic materials, properties such as band gap $$E_{g}$$ E g are critical indicators of the material’s suitability to perform a desired function. Calculating $$E_{g}$$ E g is often performed using Density Functional Theory (DFT) methods, although more accurate calculation are performed using methods such as the GW approximation. DFT software often used to compute electronic properties includes applications such as VASP, CRYSTAL, CASTEP or Quantum Espresso. Depending on the unit cell size and symmetry of the material, these calculations can be computationally expensive. In this study, we present a new machine learning platform for the accurate prediction of properties such as $$E_{g}$$ E g of a wide range of materials.

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