Bohdan Khmelnytsky National University

Cherkasy, Ukraine

Bohdan Khmelnytsky National University

Cherkasy, Ukraine
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Baryshnikov G.V.,Bohdan Khmelnytsky National University | Minaev B.F.,Bohdan Khmelnytsky National University | Minaeva V.A.,Bohdan Khmelnytsky National University | Agren H.,KTH Royal Institute of Technology
Journal of Structural Chemistry | Year: 2010

The quantum chemical DFT method with the B3LYP hybrid functional in 6-31++G(d,p) and 6-311+G(d,p) basis sets is used to calculate the equilibrium geometric parameters of different conformations of 5-(4-oxo-1,3-thiazolidine-2-ylidene)-rhodanine and its substituted form ethyl-5-(4-oxo-1,3-thiazolidine-2-ylidene)-rhodanine-3′-acetic acid applied in the synthesis of indoline and some other sensitizing dyes for solar cells. The thermodynamic parameters of four conformers and their synthesis reactions are calculated. The effect of substituents on the thermodynamic stability of the studied isomers is shown. © 2010 Pleiades Publishing, Ltd.


Minaev B.F.,Bohdan Khmelnytsky National University | Baryshnikov G.V.,Bohdan Khmelnytsky National University | Korop A.A.,Bohdan Khmelnytsky National University | Minaeva V.A.,Bohdan Khmelnytsky National University | Kaplunov M.G.,RAS Institute of Problems of Chemical Physics
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2013

Using the quantum chemical methods of the density functional theory and of the electron density topological analysis, we have studied the structure of two recently synthesized electroluminescent zinc complexes, one with aminoquinoline ligands and the other with a Schiff base (N,O-donor). The energies and intensities of vertical excitations for the molecules under study have been calculated in terms of the PM3 semiempirical approximation taking into account the configurational interaction between singly excited singlet excited states. Good agreement between calculation results and experimental data on the electron density topological characteristics and on the visible and UV absorption spectra has been obtained. © 2013 Pleiades Publishing, Ltd.


Cherpak V.,Lviv Polytechnic | Stakhira P.,Lviv Polytechnic | Minaev B.,Bohdan Khmelnytsky National University | Baryshnikov G.,Bohdan Khmelnytsky National University | And 10 more authors.
ACS Applied Materials and Interfaces | Year: 2015

We fabricated a yellow organic light-emitting diode (OLED) based on the star-shaped donor compound tri(9-hexylcarbazol-3-yl)amine, which provides formation of the interface exciplexes with the iridium(III) bis[4,6-difluorophenyl]-pyridinato-N,C2′]-picolinate (FIrpic). The exciplex emission is characterized by a broad band and provides a condition to realize the highly effective white OLED. It consists of a combination of the blue phosphorescent emission from the FIrpic complex and a broad efficient delayed fluorescence induced by thermal activation with additional direct phosphorescence from the triplet exciplex formed at the interface. The fabricated exciplex-type device exhibits a high brightness of 38 000 cd/m2 and a high external quantum efficiency. (Chemical Equation Presented). © 2014 American Chemical Society.


Cherpak V.,Lviv Polytechnic | Stakhira P.,Lviv Polytechnic | Minaev B.,Bohdan Khmelnytsky National University | Baryshnikov G.,Bohdan Khmelnytsky National University | And 10 more authors.
Journal of Physical Chemistry C | Year: 2014

The starburst carbazole derivative and phosphorescent bis-cyclometalated iridium(III) complex (IC2) were used for the preparation of multilayered "warm-white" organic light-emitting diodes (OLEDs), the emission spectra of which are modulated by the thickness of the phosphorescent layer. It was shown that the electroluminescence spectra of the fabricated devices are more extended into the visible region compared with the photoluminescence spectra of both component materials. The observed extension of the electroluminescence spectra can be assigned to the phosphorescent emission of the low-energy exciplex formed at the interface of the emissive layers. The quantum-chemical calculations performed by the DFT and (TD) DFT methods support the formation of the low-energy triplet exciplex at the interface of the IC2 layer and the neighboring layer of the starshaped carbazole-based compound, (4,4′,4″-tris[3-methylphenyl(phenyl)amino] triphenylamine, tri(9-hexylcarbazol-3-yl)amine (THCA). Indeed, the triplet excited state of such bimolecular complex corresponds to intermolecular charge transfer between IC2 and THCA. The experimentally observed electrophosphorescence of these exciplexes is induced by strong spin-orbit coupling in the THCA:IC2 complexes due to the Ir(III) heavy atom effect. With dependence on the iridium(III)-complex film thickness (5-9 nm), the CIE coordinates changed from (0.41, 0.41) to (0.52, 0.47), corresponding to the warm white and orange color. The brightness of the fabricated OLEDs at the 15 V bias was in the range from 500 to 6000 cd/m 2. © 2014 American Chemical Society.


Volyniuk D.,Kaunas University of Technology | Volyniuk D.,Lviv Polytechnic | Cherpak V.,Lviv Polytechnic | Stakhira P.,Lviv Polytechnic | And 6 more authors.
Journal of Physical Chemistry C | Year: 2013

Diphenilamino-substituted carbazoles were used as guest compounds for the preparation of highly efficient blue organic light-emitting diodes based on the phenomenon of delayed fluorescence. It was shown that the spectra of the delayed fluorescence of host-guest systems are identical to those of the prompt fluorescence and in general coincide with the photoluminescence spectra of the guest films. The congruence of the prompt and delayed fluorescence spectra is explained by the effective intermolecular triplet-singlet (T → S) energy transfer from the excited T states of the host to the S states of the guest molecules. High external electroluminescence efficiency of the fabricated electroluminescent devices, reaching 17%, is comparable to that achieved in phosphorescence-based organic light-emitting diodes. © 2013 American Chemical Society.


Baryshnikov G.V.,Bohdan Khmelnytsky National University | Minaev B.F.,Bohdan Khmelnytsky National University | Minaev B.F.,Tomsk State University | Karaush N.N.,Bohdan Khmelnytsky National University | Minaeva V.A.,Bohdan Khmelnytsky National University
Physical Chemistry Chemical Physics | Year: 2014

Nanotubes and two-dimensional sheet-like compounds containing tetraoxa[8]circulene core units are theoretically predicted. The large cavities with a diameter of 6 Å in the 2D sheets could be useful for hydrogen storage. The designed compounds are predicted to adsorb strongly in the visible region and to be a promising material for nanophotonics because of their electron-donor properties (p-type semiconductors). © 2014 the Partner Organisations.


Baryshnikov G.V.,Bohdan Khmelnytsky National University | Valiev R.R.,Tomsk Polytechnic University | Karaush N.N.,Bohdan Khmelnytsky National University | Minaev B.F.,Bohdan Khmelnytsky National University | Minaev B.F.,Tomsk State University
Physical Chemistry Chemical Physics | Year: 2014

A series of planar hetero[8]circulenes and their doubly charged ions are studied by the NICS and GIMIC methods to interpret the aromatic properties of these high symmetry species. In accordance with the performed calculations all studied hetero[8]circulenes are found to be nonaromatic compounds because paratropic and diatropic ring-currents are completely canceled yielding almost zero net current. In great contrast, the dicationic and dianionic hetero[8]circulenes demonstrate the predominant contribution of diatropic ring currents resulting in the total aromatic character of the studied doubly charged ions. This fact allows us to predict the high stability of dianionic hetero[8]circulenes and explains the extremely high stability of dicationic species observed in the mass-spectra. This journal is © the Partner Organisations 2014.


Baryshnikov G.V.,Bohdan Khmelnytsky National University | Minaev B.F.,Bohdan Khmelnytsky National University | Minaeva V.A.,Bohdan Khmelnytsky National University | Nenajdenko V.G.,Moscow State University
Journal of Molecular Modeling | Year: 2013

The single crystal architecture of the high-symmetry octathio[8]circulene and sym-tetraselenatetrathio[8]circulene is studied at the density functional theory (DFT) level with the quantum theory of atoms in molecules (QTAIMs) approach to the electron density distribution analysis. The presence of stabilizing intermolecular C - -C, C - -S and C - -Se contacts in the longitudinal and transversal projections of the single crystals is postulated on the grounds of the previous high-resolution X-ray data for octathio[8] circulene; it is supported by the present QTAIM calculations and also predicted in some new details for both circulenes. We suggest that the appearance of the observed red color for the monocrystalline octathio[8]circulene is caused by strong intermolecular interactions between the molecules in the single crystal. However, the intermolecular interactions for the sym-tetraselenatetrathio[8] circulene crystal fragment are weaker and molecular layers are more friable in comparison to octathio[8]circulene crystal structure. These lead to the absence of visible absorption for the sym-tetraselenatetrathio[8]circulene crystal. [Figure not available: see fulltext.] © 2013 Springer-Verlag Berlin Heidelberg.


Baryshnikov G.V.,Bohdan Khmelnytsky National University | Minaev B.F.,Bohdan Khmelnytsky National University | Minaev B.F.,Tomsk State University | Karaush N.N.,Bohdan Khmelnytsky National University | Minaeva V.A.,Bohdan Khmelnytsky National University
RSC Advances | Year: 2014

Novel one- and two-dimensional π-conjugated materials containing a tetraoxa[8]circulene monomer are designed on the basis of density functional theory techniques, including the periodic boundary condition for the infinite structures. These new materials are predicted to be the perspective ambipolar organic semiconductors showing a high mobility for hole and electron charge carriers. Furthermore, we demonstrate that the extension of π-conjugated tetraoxa[8]circulene units in the second dimension leads to a material with the HOMO-LUMO gap being significantly smaller than that for the 1D polymer ribbon. This fact clearly indicates the fundamental difference between the designed 1D and 2D semiconducting polymers, which constitutes the essence of modern "band-gap engineering". The consistent growth of π-conjugation determines the strong visible light absorption of the studied systems in a great contrast to the initial lack of color of the tetraoxa[8]circulene compound. The possible chemical routes to synthesize the predicted materials are discussed, including free Gibbs energy estimation for the proposed reactions. © the Partner Organisations 2014.


PubMed | Bohdan Khmelnytsky National University
Type: Journal Article | Journal: Physical chemistry chemical physics : PCCP | Year: 2014

A series of planar hetero[8]circulenes and their doubly charged ions are studied by the NICS and GIMIC methods to interpret the aromatic properties of these high symmetry species. In accordance with the performed calculations all studied hetero[8]circulenes are found to be nonaromatic compounds because paratropic and diatropic ring-currents are completely canceled yielding almost zero net current. In great contrast, the dicationic and dianionic hetero[8]circulenes demonstrate the predominant contribution of diatropic ring currents resulting in the total aromatic character of the studied doubly charged ions. This fact allows us to predict the high stability of dianionic hetero[8]circulenes and explains the extremely high stability of dicationic species observed in the mass-spectra.

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