Theoretical modelling of low band-gap organic oligomers

Amazonas, Jarlesson Gama; Guimarães, Jeconias Rocha; Costa, Sheila C.S.; Laks, Bernardo; Nero, Jordan Del

doi:10.1016/j.theochem.2005.10.034

Cited by 11 publications

(7 citation statements)

References 36 publications

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“…Besides, a large number of experimental studies are devoted to the designing of new thiophene materials, a number of pertinent theoretical studies have also been made on these materials. [42][43][44][45][46][47][48][49][50][51][52][53][54] However, an understanding of the properties of these materials still forms a pre-requisite for further development. In view of this, herein, we have attempted to understand the reactivity, aromaticity, and absorption spectra of few fused thiophene oligomers.…”

Section: Introductionmentioning

confidence: 99%

Does oligomerization in fused thiophene affect reactivity and aromaticity?

Bhattacharyya¹

2016

J Chem Sci

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Reactivity and aromaticity of a few fused thiophene oligomers and their conformers are discussed in the light of density functional theory (DFT) and conceptual density functional theory. Reactivity parameters, such as hardness (η) and electrophilicity (ω), chemical potential (μ) and energy of the HOMO (highest occupied molecular orbital) have been studied. Oligomerization raises the E HOMO of the species, which in turn increases the reactivity of the oligomers. The absorption spectra of the species are analysed using TDDFT (time dependent density functional theory). The absorption peaks show red shift with increasing size of the oligomers. Aromaticity of the species is gauged by nucleus independent chemical shift (NICS). The out-of-plane component, (NICS zz) values advocate higher aromatic character at longer distance whereas, NICS supports the reverse.

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Section: Introductionmentioning

confidence: 99%

Does oligomerization in fused thiophene affect reactivity and aromaticity?

Bhattacharyya¹

2016

J Chem Sci

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“…The geometries of the [2,2′]dithiopene S-oxide (2TO) and bridged dithiophene S-oxide (BTO) derivatives were fully optimized using semi-empirical methods (AM1 and PM3), ab initio calculations (Hartree-Fock), and density functional theory (Beckes's three-parameter hybrid [28] functional) employing the Lee, Yang and Parr correlation functional B3LYP [29]). The basis set 6-31 G* was used for all atoms in the ab initio methods; this set has already been used by several researchers studying polythiophenes [24,25,[30][31][32][33][34]. The absorption transitions were calculated from the optimized geometry in the ground state S 0 using timedependent DFT (TD-DFT) theory [35,36].…”

Section: Methodsmentioning

confidence: 99%

Structural and electronic properties of 4H-cyclopenta[2,1-b,3;4-b′]dithiophene S-oxide (BTO) derivatives with an S, S=O, O, SiH2, or BH2 bridge: semi-empirical and DFT study

2011

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In this paper, we theoretically studied the geometries, stabilities, and the electronic and thermodynamic properties of 4H-cyclopenta[2,1-b,3;4-b']dithiopene S-oxide derivatives (BTO-X, with X = BH(2), SiH(2), S, S=O, or O) using semi-empirical methods, ab initio methods, and density functional theory. The geometries and thermodynamic parameters calculated by PM3 were in good agreement with those calculated with B3LYP/6-31 G*. The band gap calculated using B3LYP/6-31 G* ranged from 3.94 eV (BTO-O) to 3.16 eV (BTO-B). The absorption λ(max) calculated using B3LYP/6-31 G* was shifted to longer wavelengths when X = BH(2), SiH(2), or S=O (due to their electron-withdrawing effects) and to shorter wavelengths for BTO-S and BTO-O as compared to the λ(max) for the thiophene S-oxide (2TO) dimer. The changes in ΔH°, ΔS°, and ΔG° calculated using both semi-empirical and DFT methods were quite similar.

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“…Also, the Fock matrix with several terms includes core, Coulomb, exchange interaction energies, and the influence of external fields energy as presented before. [22][23][24][25] This paper could be understood as a two-terminal molecular device within specific atomic sites to simulate the gate terminal. The intention is find out manifestations of the transport properties unusual in ordinary devices.…”

Section: Methodology and Systemmentioning

confidence: 99%

Design of Highly Integrated Organic Nanodevice

Silva¹,

Nero²

2009

Jnl of Comp & Theo Nano

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In recent experimental work it was found that for a current-voltage bistability in/an organic semiconductor working as multilevel switching (B. C. Das and A. J. Pal, Organ. Electron. 9, 39 (2008). Due to the experimental motivation, we simulate the electronic distribution properties as charge accumulation/depletion-voltage and capacitive effects-voltage of a similar organic compound by means of the quantum mechanics methodology. Also, our theoretical results are consistent with: (i) similar behavior for positive bias when compared with experimental one; (ii) prediction as asymmetric feature for negative bias, e.g., asymmetric majority carrier transportation curve for Ponceau SS device; (iii) resonance tunneling type conduction in the I-V signature. For both bias (positive and negative) the resonance is addressed and it explains as a bi-directional molecular transistor or memory device.

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Theoretical modelling of low band-gap organic oligomers

Cited by 11 publications

References 36 publications

Does oligomerization in fused thiophene affect reactivity and aromaticity?

Does oligomerization in fused thiophene affect reactivity and aromaticity?

Structural and electronic properties of 4H-cyclopenta[2,1-b,3;4-b′]dithiophene S-oxide (BTO) derivatives with an S, S=O, O, SiH2, or BH2 bridge: semi-empirical and DFT study

Design of Highly Integrated Organic Nanodevice

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