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P. Veerapandian

Bio: P. Veerapandian is an academic researcher from Bharathidasan University. The author has contributed to research in topics: HOMO/LUMO & Density functional theory. The author has an hindex of 1, co-authored 1 publications receiving 125 citations.

Papers
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TL;DR: A series of 15 donor-π-acceptor type vinyl coupled triazene derivatives with different acceptors with good NLO and optoelectronic properties are designed, and 10 out of 15 designed candidates are found to have excellent N LO and optoeselectronic properties.
Abstract: Triazenes are a unique class of polyazo compounds containing three consecutive nitrogen atoms in an acyclic arrangement and are promising NLO candidates. In the present work, a series of 15 donor-π-acceptor type vinyl coupled triazene derivatives (VCTDs) with different acceptors (−NO2, −CN, and −COOH) have been designed, and their structure, nonlinear response, and optoelectronic properties have been studied using density functional theory and time-dependent density functional theory methods. B3LYP/6-311g(d,p) optimized geometries of the designed candidates show delocalization from the acceptor to donor through a π-bridge. Molecular orbital composition analysis reveals that HOMO is stabilized by the π-bridge, whereas acceptors play a major role in the stabilization of LUMO. Among the three acceptors, nitro derivatives are found to be efficient NLO candidates, and tri- and di-substituted cyano and carboxylic acid derivatives also show reasonably good NLO response. The effect of solvation on these propertie...

150 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the density functional theory (DFT) was used to calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of new Y-type chromophores.
Abstract: New Y-type chromophores FTC-yh1 and FTC-yh2 containing bis(N,N-diethyl)aniline as a novel electron-donor, thiophene as a π-conjugated bridge and tricyanofuran (TCF) as an acceptor have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed better thermal stability with their decomposition temperatures all above 240 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-A containing 25 wt% chromophore FTC-yh1 displayed a value of 149 pm V−1 at 1310 nm, and the doped film-B containing FTC-yh2 showed a value of 143 pm V−1 at the concentration of 25 wt%. These values are almost four times higher than the EO activity of usually reported traditional single (N,N-diethyl)aniline nonlinear optical (NLO) chromophores FTC. High r33 values indicated that the double donors of the bis(N,N-diethyl)aniline unit can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of the new chromophores as advanced material devices.

66 citations

Journal ArticleDOI
TL;DR: In this article, the pyrrole moiety bridge has been modified with the electron withdrawing group (−Br, −NO2) substituted benzene ring, and side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole-dipole interactions.
Abstract: Three novel second order nonlinear optical chromophores based on julolidinyl donors and tricyanovinyldihydrofuran (TCF) acceptors linked together via modified pyrrole π-conjugation (chromophores A and B) or thiophene moieties (chromophore C) as the bridges have been synthesized and systematically characterized. In particular, the pyrrole moiety bridge has been modified with the electron withdrawing group (–Br, –NO2) substituted benzene ring. The introduction of side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole–dipole interactions so as to translate their hyperpolarizability (β) values into bulk EO performance more effectively than chromophore C. Moreover, DFT calculations suggested that the additional electron withdrawing groups in chromophores A and B could increase the β value compared to that of chromophore D without substituted phenyl groups, and they showed different influences on the solvatochromic behavior, thermal stability, and electro-optic activity of the chromophores. EO responses (r33 values) of guest–host polymers containing pyrrole-bridged chromophores were reported. Incorporation of chromophores A and B into APC provided large electro-optic coefficients of 86 and 128 pm V−1 at 1310 nm with a high loading of 30 wt%. Film-C/APC containing 25 wt% of chromophore C provides an EO coefficient of 98 pm V−1.

63 citations

Journal ArticleDOI
TL;DR: It is found that introduction of an electron-donating group into the BF2-napthyridine complex improves the hole transport properties and provides useful clues in designing new materials for organic light emitting diodes (OLED).
Abstract: Five napthyridine-based fluorine-boron (BF2-napthyridine) conjugated compounds have been theoretically designed, and subsequently, their photophysical properties are investigated. The influence of electron-donating and electron-withdrawing groups attached with the N∧C∧O moiety of BF2-napthyridine molecule has been interpreted. The optoelectronic properties, including absorption spectra and emission spectra of the BF2-napthyridine derivatives are studied using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) based methods. Different characteristics, such as HOMO-LUMO gap, molecular orbital density, ionization potential, electron affinity, and reorganization energy for hole and electron, are calculated. All these molecules show excellent π-electron delocalization. TD-DFT results illustrate that the amine-substituted BF2-napthyridine derivative has the highest absorption and emission maxima; it also shows a maximum Stoke shift. These results are well-correlated with the structural parameters and calculated HOMO-LUMO gap. Moreover, it is found that introduction of an electron-donating group into the BF2-napthyridine complex improves the hole transport properties and provides useful clues in designing new materials for organic light emitting diodes (OLED). As a whole, this work demonstrates that electron-donating and electron-withdrawing groups in BF2 derivatives can extend their effectiveness toward designing of OLED materials, vitro cellular studies, ex vivo assays, and in vivo imaging agents.

56 citations

Journal ArticleDOI
TL;DR: In this paper, Bithiophene azo derivatives (BTAs) containing thiazole moiety have been reported recently, and seven of them along with five new candidates have been tested for optoelectronic properties using DFT/TDDFT computations.

54 citations

Journal ArticleDOI
TL;DR: In this article, a series of novel second-order nonlinear optical chromophores containing additional heteroatoms in donor moieties has been synthesized and systematically characterized, which exhibited both good thermal stability and good solubility in common organic solvents such as chloroform, acetone and N, N-dimethyl formamide.

52 citations