A TD-DFT Simulation on Organic Polymer: The Case of PEDOT

We present a comprehensive analysis on how the electronic structure and the optical properties of an organic polymer can be modulated, based on the example of the dinitrosobenzene polymer (1). Using a combination of computational and experimental tools, we explore the effects of solid-state packing, backbone torsion, surface adsorption, the conjugation in the aromatic core, and substituents. The band gap (Eg) and optical spectrum of 1 are calculated using both GW-BSE with zero-gap renormalization (ZGR) and hybrid TD-DFT, with the former method predicting a value (2.41 eV) in excellent agreement with our diffuse reflectance spectroscopy measurements (2.39 eV). Using GW-BSE-ZGR, changes occurring upon solidstate packing are separated into a contribution arising from (i) the change in the torsional angle and (ii) the change in the screened Coulombic interaction, which strongly effects the exciton binding energies. Comprehensive hybrid TD-DFT calculations find that the effects of substituents on Eg and on transport properties can mostly be explained through changes in the torsional angle, and predict a linear dependence between it and Eg. Extending the conjugation in the aromatic core is found to enhance transport properties and narrow Eg, identifying future synthetic targets. Atomic force microscopy and spectroscopic ellipsometry are used to study 1 adsorbed to a (111) gold surface (1@Au), with the latter method showing a significant narrowing of the band gap to 0.68 eV, in good agreement with TD-DFT predictions.

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Determination of the absolute configuration of conformationally flexible molecules by simulation of chiro-optical spectra: a case study

RSC Advances ◽

10.1039/c9ra03526e ◽

2019 ◽

Vol 9 (32) ◽

pp. 18165-18175 ◽

Cited By ~ 4

Author(s):

Michele Mancinelli ◽

Roberta Franzini ◽

Andrea Renzetti ◽

Emanuela Marotta ◽

Claudio Villani ◽

...

Keyword(s):

Absolute Configuration ◽

Organic Molecules ◽

Optical Spectra ◽

Dft Simulation ◽

Flexible Molecules ◽

Td Dft ◽

The Absolute

The absolute configuration (AC) assignment of two very flexible organic molecules by TD-DFT simulation of ECD spectra is evaluated by modifying the calculation level in the various steps of the AC assignment process.

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TD-DFT Simulation and Experimental Studies of a Mirrorless Lasing of Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)]

Polymers ◽

10.3390/polym13091430 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1430

Author(s):

Mamduh J. Aljaafreh ◽

Saradh Prasad ◽

Mohamad S. AlSalhi ◽

Raya H. Alhandel ◽

Reem A. Alsaigh

Keyword(s):

Dft Calculations ◽

Density Functional ◽

Experimental Studies ◽

Optical Gain ◽

Functional Theory ◽

Time Resolved ◽

Dft Simulation ◽

Td Dft ◽

Lowest Unoccupied Molecular Orbital ◽

Benzene Toluene

In this work, we investigate the TD-DFT simulation, optical, and mirrorless laser properties of conjugated polymer (CP) Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], also known as (PFO-co-PPV-MEHB) or ADS125GE. TD-DFT calculations were performed for three monomer units with truncated tails using time-dependent density functional theory (TD-DFT) calculations. The calculations showed a highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) structure and a very high oscillator strength of 6.434 for the singlet-singlet transition at 374.43 nm. Experimentally, the absorption and fluorescence spectra were examined at various concentrations in verity of solvents, such as benzene, toluene, and hexane. The experimental results obtained in hexane were comparable with theoretical UV-VIS spectra calculated under vacuum. Amplified spontaneous emission (ASE) spectra peaked at approximately 509 nm for CO PFO-co-PPV-MEHB in solution and were obtained at suitable concentrations and pump energies. Additionally, the photochemical stability of this CP and coumarin (C510) were compared. Time-resolved spectroscopy (TRS) studies with a sub-nanosecond resolution were performed for the CO under various pump energies. These results showed the excited state dynamics and single-pass optical gain of CO PFO-co-PPV-MEHB.

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Stereodynamic Analysis of New Atropisomeric 4,7-Di(naphthalen-1-yl)-5,6-dinitro-1H-indoles

Synlett ◽

10.1055/s-0037-1609908 ◽

2018 ◽

Vol 29 (16) ◽

pp. 2161-2166 ◽

Cited By ~ 4

Author(s):

Giovanni Petrillo ◽

Michele Mancinelli ◽

Angela Pagano ◽

Emanuela Marotta ◽

Andrea Mazzanti ◽

...

Keyword(s):

Kinetic Analysis ◽

Absolute Configuration ◽

Indole Ring ◽

Electronic Circular Dichroism ◽

X Ray ◽

Dft Simulation ◽

Rotational Barriers ◽

Td Dft ◽

The Absolute ◽

Circular Dichroïsm

A series of atropisomeric molecules containing the indole ring and two stereogenic axes were prepared. The four atropisomers were resolved by enantioselective HPLC. The rotational barriers of the indole–naphthyl axes were evaluated by means of kinetic analysis either by NMR or enantioselective HPLC. The absolute configuration of the atropisomers was determined by a combination of X-ray spectroscopy and TD-DFT simulation of electronic circular dichroism spectra.

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Theoretical Studies on the Structural, Electronic and Optical Properties of the New π-conjugated Copolymers Based on Carbazole and Thiophene

Journal of Scientific Research ◽

10.3329/jsr.v4i1.7450 ◽

2011 ◽

Vol 4 (1) ◽

pp. 119 ◽

Cited By ~ 1

Author(s):

Z. El Maliki ◽

M. Bouachrine ◽

M. Hamidi ◽

L. Bejjit ◽

M. Haddad

Keyword(s):

Optical Properties ◽

Molecular Geometry ◽

Dft Method ◽

Optoelectronic Properties ◽

Polymer Materials ◽

Organic Polymer ◽

Excitation Energies ◽

Electronic And Optical Properties ◽

Td Dft ◽

Homo Lumo

This work reports a theoretical investigation of π-conjugated oligomers constituted by n units (n = 1-4) based on carbazole and ethylenedioxythiophene. The molecular geometry, torsional potential, electronic and optical properties of the oligomers [Cbz-(Edot)n-Cbz] (n = 1-4) are investigated using DFT (B3LYP/3-21G*) calculations. The discussion is focused on the influence of chain length on the properties of these copolymers. The analyses of torsional angles for [Cbz-(Edot)4-Cbz] reveal that the structure has a anti-planar conformation. The electronic properties of the molecules, HOMO, LUMO and Eg (HOMO-LUMO), are studied using B3LYP functional. The results have been compared with those of thiophene and ethylenedioxythiophene. The lowest excitation energies (Eex) and the maximal absorption wavelength (λabs) are studied using the TD/DFT, ZINDO and CIS methods. The electronic transitions of the absorption spectrum derived by TD/DFT method give useful structural and electronic information for designing novel conducting organic polymer materials. The bridging effect by C=C(CN)2 on the optoelectronic properties of the (carbazole-thiophene-carbazole) comonomer is investigated. Keywords: Conducting polymer; Carbazole-(Ethylenedioxythiophene)n-Carbazole comonomers; DFT Optoelectronic properties; absorption coefficient; Bridging effect. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i1.7450J. Sci. Res. 4 (1), 119-133 (2012)

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Effect of Illumination on Organic Polymer Thin-Film Transistors

MRS Proceedings ◽

10.1557/proc-771-l10.17 ◽

2003 ◽

Vol 771 ◽

Cited By ~ 3

Author(s):

Michael C. Hamilton ◽

Sandrine Martin ◽

Jerzy Kanicki

Keyword(s):

Thin Film ◽

Thin Film Transistors ◽

Drain Current ◽

Charge Carriers ◽

Electrical Performance ◽

Organic Polymer ◽

Light Illumination ◽

Polymer Thin Film ◽

Channel Region ◽

White Light Illumination

AbstractWe have investigated the effects of white-light illumination on the electrical performance of organic polymer thin-film transistors (OP-TFTs). The OFF-state drain current is significantly increased, while the drain current in the strong accumulation regime is relatively unaffected. At the same time, the threshold voltage is decreased and the subthreshold slope is increased, while the field-effect mobility of the charge carriers is not affected. The observed effects are explained in terms of the photogeneration of free charge carriers in the channel region due to the absorbed photons.

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The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

10.26434/chemrxiv.13204985.v1 ◽

2020 ◽

Author(s):

Tulin Okbinoglu ◽

Pierre Kennepohl

Keyword(s):

Density Functional ◽

Chemical Properties ◽

Functional Theory ◽

Rotational Barriers ◽

Td Dft ◽

Nitrogen Bonds ◽

X Ray Absorption ◽

Related Compounds ◽

And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

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