Dmytro Volyniuk

Kaunas University of Technology · Department of Polymer Chemistry and Technology

In contrast to many donor-acceptor type organic luminophores exhibiting thermally activated delayed fluorescence (TADF), two deep blue TADF emitters designed in this work contain only typical electron accepting moieties with the different electron accepting abilities. Derivatives of benzophenone and diphenylsulfone substituted with phenothiazine-5,...

Two highly emissive carbazole-containing thiazole-fused oxadiazaborinines were designed and synthesized. These N,O-chelated organoboron dyes displayed large Stokes shifts and remarkable solvatofluorochromism in solutions, as well as good thermal stability and comparatively high photoluminescence quantum yields (up to 34%) in the solid state. The pr...

Additional energy loss pathways which occur in blue electrophosphorescent devices via through‐space charge transfer (TSCT) states of bipolar hosts are identified for the first time in this study. Blue phosphorescent organic light‐emitting diodes (PhOLEDs) with maximum external quantum efficiency from 22.7 to 30.5% are fabricated using new bipolar d...

New triphenylethylene-based derivatives, containing 2,6-di-tert-butylcarbazole or 9,9-dimethyl-9,10-dihydroacridine as donor moieties and phenylene or tetrafluorophenylene linking bridges were synthesised by Heck coupling and characterized. The synthesized compounds emitted blue light in the solid state with emission maxima in the range of 478–487...

Carbazole or acridan-substituted dibenzo[a,c]phenazines (CzDbp and AcDbp, respectively) were synthesized and investigated exploiting the donor–acceptor-donor (D-A-D) architecture expecting thermally activated delayed fluorescence (TADF) in both cases. Unexpectedly, while experimental microseconds-lived TADF behaviour was observed for AcDbp efficien...

A rare example of exciplex-forming systems with highly efficient thermally activated delayed fluorescence (TADF) exhibiting reverse intersystem crossing (RISC) yields of 97 and 96 % and RISC rates of 5.1×10⁷ and 3.6×10⁷ s⁻¹ at 300 K are developed for oxygen probing and organic light-emitting diodes (OLEDs). The exciplexes forming systems consist of...

Three new quinoline and di‐ tert ‐butyl phenothiazine isomeric derivatives were synthesized and characterized towards applications for oxygen sensing and optical information multi‐coding. The compounds with phenylene linker showed outstanding phase‐dependent reversibility between ON/OFF stages (low and high emission intensity, drastic shifting of e...

High-quality host materials are indispensable for the construction in the emitting layer of efficient organic light-emitting diodes (OLEDs), especially in a guest and host system. The good carrier transport and energy transfer between the host and emitters are out of necessity. In this work, a wide bandgap and bipolar organic compound, 2,2′-bis(4,5...

Heavy atom-free derivatives of para and ortho isomers of benzotrifluoride and 3,7-di-tert-butyl-phenothiazine were designed, synthesized and studied as active materials for optical sensors of oxygen using both theoretical and experimental approaches. Using these moieties and substitution patterns, we managed to demonstrate room-temperature phosphor...

Derivatives of trifluorobiphenyl and 3,6-di-tert-butylcarbazole were synthesised as potential components of emitting layers of OLEDs. Molecular design of the compounds was performed taking into consideration the hydrogen bonding ability of the fluorine atom and electron-donating ability of the carbazole moiety. Their toluene solutions exhibited ver...

Flexible versus rigid molecular structures of donor-acceptor-donor type compounds are investigated with respect to efficiency of thermally activated delayed fluorescence (TADF) by theoretical and experimental approaches. Three highly efficient TADF emitters based on flexible diphenylsulfone and rigid dibenzothiophene-dioxide as acceptor units and d...

Article is available via https://authors.elsevier.com/c/1bX1S3HXll8~fw . Two 3,3‘-bicarbazole derivatives, with triphenylsilyl and toluenesulfonyl moieties attached to 9,9‘-positionswere synthesized and their properties were studied. The compounds exhibited high triplet energies of 2.9 eVwhich made them useful for efficient triplet exciton harvest...

A new series of TADF emitters with donor-acceptor or donor-acceptor-donor structure containing 2,7-dimethoxycarbazole donor moiety and diphenylsulfone acceptor unit were synthesized and employed in non-doped sky-blue organic light emitting diodes with the external quantum efficiency reaching 9.0%. Thermal, optical and photophysical properties of fo...

Photoswitchable organic field-effect transistors (OFETs) with embedded photochromic materials are considered as a promising platform for development of organic optical memory devices. Unfortunately, the operational mechanism of these devices and guidelines for selection of light-sensitive materials are still poorly explored. In the present work, a...

Four new donor-acceptor compounds were designed, synthesized and investigated by theoretical and experimental approaches aiming to estimate effect of the structure of a donor on the properties of potential OLED emitters. Because of the different electron-donating abilities of the nitrogen-containing heterocycles, derivatives of xanthenone containin...

Two spiro-MeTAD compounds (1 and 2) were synthesized, characterized by experimental and quantum mechanical methods, and used as hole transporting materials (HTMs) in perovskite solar cells (PSC). The new compounds differ from spiro-OMeTAD only by the presence of methyl substituents as compared to methoxy groups. This modification results in absorpt...

In this work, we report on a series of diphenylsulfone derivatives substituted by 2-(trifluoromethyl)-phenothiazinyl, 10,11-dihydro-5H-dibenz[b,f]azepinyl, 5H-dibenz[b,f]azepinyl, 4-methoxy-carbazolyl and 1,2,3,4-tetrahydrocarbazolyl moieties. Utilization of such donating units provided high triplet levels (2.99–3.12 eV) of the designed compounds....

Two compounds, having dimethoxy-substituted triphenylamino groups and fragments of cyanoacrylic acid or rhodanine-3-acetic acid were prepared and characterized. Their optical, photophysical, thermal, electrochemical, photoelectrical and nonlinear optical properties were investigated. Both derivatives showed ability of glass-formation with glass tra...

Materials with high triplet energies have attracted great attention for their application in exciplex-based or thermally activated delayed fluorescence-based organic light-emitting diodes. To study the correlation between triplet energy and chemical structure, six compounds with typical donor-acceptor-donor structures were designed, synthesized, an...

Aiming to design blue fluorescent emitters with high photoluminescence quantum yields in solid-state, nitrogen-containing heteroaromatic 9,9-dimethylacridine was refined by tetraphenylethene and triphenylethene. Six tetra-/triphenylethene-substituted 9,9-dimethylacridines were synthesized by the Buchwald-Hartwig method with relatively high yields....

In the search of universal host materials for organic light emitting diodes a new series of bipolar host materials containing methoxy-substituted carbazoles as the electron-donating and dibenzofuran as an electron-accepting units were designed and synthesized. Different linking topologies and number of methoxy groups attached to carbazolyl moiety w...

Towards highly efficient doping-free organic light-emitting diodes, five benzonitrile-based emitters with different substitution pattern were designed exploiting symmetrical donor-acceptor-donor and asymmetrical donor-acceptor-donor* structures. As it was predicted by theoretical calculations, different thermally activated delayed fluorescence of d...

Ten luminophores based on tetrahydrodibenzophenanthridine and phenanthroimidazole were designed, synthesized and characterized for their thermal, electrochemical, electro‐optical, charge‐transporting characteristics and electroluminescent properties. The blue luminophores exhibited high photoluminescence quantum yields of 66‐93% in toluene solution...

meta-Substituted benzophenones bearing tetrahydrocarbazole, phenoxazine and 2,7-ditert-butyl-9,9-dimethylacridine moieties were synthesized as materials exhibiting both thermally activated delayed fluorescence and aggregation induced emission enhancement. The derivatives showed improved HOMO and LUMO separation compared to that of the corresponding...

Strongly medium dependent capability to exhibit not only prompt/delayed thermally-activated fluorescence but also aggregation-induced phosphorescence or exciplex emission is demonstrated either for solutions or for solid samples of acridan-based luminophores. Multicolour emissions of different nature were detected and studied for donor-acceptor der...

This paper primarily deals with the development of highly efficient phosphorescent iridium (III) complex based on benzoimidazophenanthridine as main ligand. The potential of this complex, as phosphorescent emitter for optoelectronic applications, was screened by different methods, including luminescence spectrometry, cyclic voltammetry, thermogravi...

Efficient TADF relies on effective reverse intersystem crossing (rISC) from triplet to singlet manifold, and therefore transition rate associated with this process must outcompete non-radiative decay rate of the triplets. Herein the issue of non-radiative triplet quenching in benzophenone-derived compounds frequently employed as blue TADF emitters...

Recent efficiency records of organic photovoltaics (OPV) highlight stability as a limiting weakness. Incorporation of stabilizers is a desirable approach for inhibiting degradation - it is inexpensive and readily up-scalable. However, to date, such additives have had limited success. We show that beta-carotene (BC), an inexpensive and green, natura...

Carbazolyl- and 1,2,3,4-tetrahydrocarbazolyl-substituted benzothiadiazoles were prepared by Pd-catalyzed Buchwald-Hartwig and Heck reactions. Photophysical, electrochemical, thermal, charge-transporting properties, and performance in organic light emitting diodes (OLEDs) of the derivatives with donor-π-acceptor-π-donor and donor-acceptor-donor stru...

A series of three-armed fluorescent emitters based on a 1,3,5-triazine acceptor as the central core and phenothiazine or phenoxy moieties as the different peripheral units, are designed and synthesized. All of them exhibit aggregation-induced emission enhancement and thermally activated delayed fluorescence. Photoluminescence quantum yields exceede...

Two new carbazole-containing aromatic imides were synthesized by three-step synthetic pathway with the moderate yields up to 76%. The compounds were investigated theoretically. TD-DFT computational studies revealed low singlet-triplet energy differences. The compounds were found to have relatively high thermal stability with 5% mass loss temperatur...

The synthesis of new iridium(III) complexes containing a 2-(benzo[b]selenophen-2-yl)pyridine ligand is reported along with their photophysical, thermal, electrochemical and electroluminescent properties. These complexes are characterized by deep red phosphorescence with photoluminescence quantum yields exceeding 31% in the solid state. Solid layers...

Fabrication of multilayered organic light-emitting diodes (OLEDs) through solution process involves several challenges, especially in preventing dissolution of prior layers during subsequent coating. To overcome, extensive efforts had been made in developing cross-linkable materials. In this work, a thermally cross-linkable hole-transporting materi...

Two new analogues of a popular host material, meta-bis(N-carbazolyl)phenylene (mCP), bearing either methoxy- (mCP-OMe) or tert-butyl (mCP-t-Bu) substituents at C-3 and C-6 positions of carbazole moieties were synthesized and characterized. These materials exhibit higher glass-transition temperatures (79 and 145 °C) than mCP (67 °C). They show rever...

In the domain of organic photovoltaic (OPV) devices, the design of new materials faces the extraordinary challenge to satisfy two opposite requirements: the new materials should exhibit weak intermolecular interactions at the donor-acceptor interface, but strong intermolecular interactions and good charge transport properties in the bulk. In an eff...

Fluorescent dye based on 8-brominated benzo[4,5]thiazolo[3,2-c][1,3,5,2]oxadiazaborinine core was synthesized from benzo[d]thiazol-2-amine. The new boron complex can be effectively modified by palladium-catalyzed Suzuki-Miyaura cross-coupling reaction with (het)arylboronic acids. This reaction allows a valuable regioselective postfunctionalization...

Tetraphenylethene (TPE) has been demonstrated to be an effective core molecule for generating excellent aggregation-induced emissions (AIE). Herein, we propose TPE moieties decorated with different biphenyl or anthracenyl fragments to avoid the crystallization of neat film and simultaneously harvest blue AIE. The two synthesized compounds, 2-(4-bip...

Two new asymetric D–A–D′ type compounds containing benzophenone and diphenylsulfone as electron accepting core, and acridan and thianthrene as electron donating moieties were design as multifunctional materials. The influence of different acceptor and donor units on thermally activated delayed fluorescence and room temperature phosphorescence was i...

New efficient carbazole-based emitters containing tetra-/triphenylethene units were developed for boosting efficiency of non-doped fluorescent organic light-emitting diodes. Comparable study of the properties of derivatives containing one or two tetra-/triphenylethenyl units was performed using various experimental and theoretical techniques. Depen...

Diphenylsulfones substituted by acridan, carbazole, phenothiazine and phenoxazine moieties were synthesized and characterized by thermal analysis, UV-, steady-state and time-resolved luminescent spectrometries, cyclic voltametry. Quantum chemical calculations on the molecular level were performed to interpret photophysical properties of the derivat...

Isomeric quinoline and 9-phenylcarbazole derivatives with different linking topology were synthesized as versatile exciplex-forming materials. Their exciplex forming properties were examined. The studied compounds showed dual electron-donating or accepting nature and formed blue emitting excited complexes with acceptor 2,4,6-tris[3-(diphenylphosphi...

Aiming to develop all‐organic bipolar semiconductors with high charge mobility and efficient E‐type fluorescence (so‐called TADF) as environmentally‐friendly light‐emitting materials for optoelectronic applications, four noble metals‐free dyes with linear and V‐shapes were designed using accepting pyridine‐3,5‐dicarbonitrile and donating carbazole...

Two exciplexes were detected for the first time for the known exciplex-forming system consisting of electron donating 1,3-bis(N-carbazolyl)benzene and electron accepting 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine. Exploiting thermal treatment, sky-blue (high-energy) and orange (low-energy)...

Four new compounds containing accepting oxadiazole and donating carbazole moieties were designed, synthesized and characterized by different techniques ranging from theoretical calculation to testing in electroluminescent devices. The derivatives show high thermal stability with 5% weigh loss temperature ranging from 359 to 383 °C and glass formati...

To provide high exciton utilization in organic light emitting diodes, phthalimide derivatives were designed and synthesized as exciplex-forming materials. Due to high triplet levels (2.92–3.11 eV) and ionization potentials (7.18–7.29 eV), the developed phthalimide derivatives were found to be not only appropriate accepting materials for the formati...

Multi-functional luminophores exhibiting thermally activated delayed fluorescence (TADF), aggregation induced emission enhancement and sky-blue ↔ blue colour-changing were designed and synthesized. For the first time, perfluorobiphenyl was used as acceptor in the design of TADF compounds, while, non-substituted and tert-butyl substituted 9,9-dimeth...

Naphthyl substituted triphenylamine and its derivatives with bromine atoms were synthesized and investigated. The respective glass transition temperatures of the materials were estimated to be in a range 65–137 °C, which can provide morphologically-stable amorphous films for applications in organic light emitting diodes. The compounds possess adequ...

A family of highly emissive benzo[4,5]thiazolo[3,2-c][1,3,5,2]oxadiazaborinines, conjugated with donor 4-dimethylaminophenyl group, was designed and synthesized. Their photophysical, both in solution and in the solid state, and structural properties were investigated. The influence of donor and acceptor substituents (R) in the benzothiazole unit on...

New derivative acridan and isophthalonitrile (DAcIPN) was designed and synthesized as efficient TADF-type emitter with photoluminescence quantum yield of doped solid-state layer reaching 83%. Tuning of emission and efficiency of TADF emitter was performed by controlling the singlet-triplet energy splitting. Three important effects concerning the so...

Based on the theoretical calculations of excited states and semiconducting properties, a new 1,8-naphthalimide derivative having an electron-donating 1-pyrenyl group at the C-4 position was designed and synthesized. This derivative exhibited an excellent thermal stability and bipolar charge carrier transport ability. It was successfully utilized as...

Star shaped, C3-symmetric, tetraphenylethene (TPE) and 2,3,3-triphenyl acrylonitrile (TPAN) substituted truxenes 7, 8 and 9 were designed and synthesized by the Pd-catalyzed Suzuki and Sonogashira cross-coupling reactions. The TPE substituted truxenes 7 and 8 show aggregation-induced emission (AIE) behaviour whereas TPAN substituted truxene 9 shows...

Two derivatives of tetrafluorophenylcarbazole and tri/tetraphenylethylene displaying aggregation-induced emission enhancement were synthesized and investigated, by theoretical and experimental tools. The synthesized compounds exhibit efficient emission in solid state with fluorescence intensity maxima at 511 and 502 nm and photoluminescence quantum...

A series of [Ir(C^N)2(NN)][PF6] complexes in which NN is 5-(4-ethynylphenyl)-2,2’-bipyridine has been synthesized and characterized by spectroscopic methods. All novel complexes exhibit unique singlet-triplet dual emission in solution with two...

In the domain of OLED applications, organic electroactive materials play a crucial role. In order to allow for more flexibility in their properties, methoxy- or other substituents are frequently used. However, undesirable modifications in their polarity may be additionally obtained, which is particularly important in the case of TADF-based OLEDs. I...

Two compounds, bearing benzophenone unit as an acceptor core, tetrahydrocarbazole, and 2-phenylindole donor moieties, were designed and synthesized by employing one-step nucleophilic aromatic substitution reaction. Their photophysical properties, based on theoretical calculations and experimental measurements, as well as electrochemical and photoel...

Excited state dynamics of trinary star-shaped dendritic compounds with triphenylamine arms and different cores were studied by means of time-resolved fluorescence and transient absorption. Under optical excitation, nonpolar C3 symmetry molecules form polar excited states localized on one of the molecular substituents. Conformational excited state s...

Derivatives of indole and benzo[b]carbazole were prepared by employing efficient regioselective acid-catalyzed synthesis of 1H, 1-methyl and 1-naphthylindole with o-phthaldialdehyde. The synthesized compounds were characterized by NMR, IR and mass spectrometries. They form molecular glasses with glass transition temperatures ranging from 86 to 116...

Derivatives of 9‐phenyl‐9H‐carbazole were synthesized as efficient emitters exhibiting both thermally activated delayed fluorescence and aggregation induced emission enhancement. Effects of methoxy and tert‐butyl substituents at the different positions of carbazolyl groups on the properties of the emitters were studied. Depending on the substitutio...

Bicarbazole derivative 4,4'-(9H,9'H-[3,3'-bicarbazole]-9,9'-diyl)bis(3-(trifluoromethyl)benzonitrile), denoted as pCNBCzoCF3 was synthesized and tested for white OLED applications. pCNBCzoCF3 demonstrated extremely small value of the singlet-triplet energy gap that caused intensive thermally-activated delayed fluorescence (TADF). In addition, this...

Three donor-π-acceptor-π-donor multichromophore fluorenone-centered compounds are presented. The π-bridges between fluorenone and carbazole donors contain ethynyl moieties linked to various branched spacing moieties, such as triphenylamine, 1,3,5-triphenylbenzene and 9-phenylcarbazole. Differences in photophysical, photoelectrical, thermal and char...

A series of 1,3-thiazole based organoboron complexes have been designed and synthesized by acylation of 2-amino-4-subsituted-1,3-thiazoles with (4-dimethylamino)benzoyl chloride, and the subsequent BF2 complexation reaction. The influence of substituents in position 4 of the thiazole ring on photophysical properties of the complexes has been invest...

Elaboration of the appropriate host materials proved to be not less important for the fabrication of a highly efficient OLED, than the design of emitters. In present work we show how by simple variation of molecular structure both blue emitters exhibiting delayed fluorescence and ambipolar high triplet energy hosts can be obtained. The compounds wi...

Correction for ‘Solution-processable naphthalene and phenyl substituted carbazole core based hole transporting materials for efficient organic light-emitting diodes’ by Sudhir Kumar et al. , J. Mater. Chem. C , 2017, 5 , 9854–9864.

New carbazole-chloropyridine donor-acceptor compounds were obtained with the yields of 49–77% by a one-step catalyst-free nucleophilic substitution reaction of pentachloropyridine and carbazole. The structures of the compounds were confirmed by ¹H, ¹³C NMR and IR spectroscopy and mass spectrometry. X-ray single crystal diffraction analysis was perf...

Series of compounds consisting of carbazole arms and 1,3,5-triazine core linked by amino group were synthesized and characterized. The clear relationship between electrochemical properties, quantum efficiency, charge transport properties and structure were estimated. The exciplex-forming properties of the synthesized compound as donor, and two know...

A new luminescent ambipolar semiconductor consisting of 1,8-naphthalimide as an electron-accepting moiety and carbazole as an electron-donating moiety has been synthesized and characterized. The synthesized compound as ambipolar semiconductor has been investigated by using density functional theory calculations coupled with the charge-hopping model...

Phenylethenyl substituted 10-alkylphenoxazines were synthesized by a multi-step synthetic route. The derivatives were characterized by thermo-gravimetric analysis, differential scanning calorimetry, electron photoemission and time of flight technique. The materials were found to show very high thermal stability having initial thermal degradation te...

Seven new derivatives of phenanthro[9,10-d]imidazole having differenet substituents at the 1st and the 2nd positions of phenanthroimidazole moiety were synthesized and characterized. The comparative study of their properties was performed employing thermal, optical, electrochemical and photoelectrical measurements. Properties of the newly synthesiz...

Solution-processable molecular hole transporting material (HTM) is extremely crucial in order to realize the low cost, high throughput, and roll-to-roll fabrication of large area organic light emitting diodes for display and lighting applications. In this report, a series of naphthalene and phenyl substituted carbazole core based HTMs, 3-(1-naphthy...

A series of carbazolyl-substituted quinazolinones were designed and synthesized by the Pd-catalyzed Buchwald-Hartwig, Suzuki and Heck cross-coupling reactions. Their optical, photophysical, thermal, electrochemical, and electroluminescent properties were investigated. The characterization of the synthesized compounds was carried out using experimen...

Four phenanthroimidazole-based bipolar compounds having electron-donating carbazole or diphenylamino moieties were synthesized and characterized. All compounds form glasses and exhibit high glass transition temperatures ranging from 183 to 239 °C. Solid state blue emission was detected for all synthesized compounds and quantum yields in solid state...

The derivatives of carbazole and tetraphenylethylene exhibiting aggregation-induced emission and 4,4′,4′′-tris[3-methylphenyl(phenyl)amino]triphenylamine were used for the preparation of organic light-emitting diodes the electroluminescence spectra of which include exciton and exciplex emissions. The low-energy exciplex emission of the electrolumin...

In the present work we have shown the double-channel emission from organic exciplexes coupled to inorganic nanoparticles. The process is demonstrated by yellow-green emission in light-emitting diodes based on organic exciplexes hybridized with perovskite-type dispersed BaZrO3 nanoparticles. Such double-channel emission provides a broadening of the...

Triphenylethene moiety decorated with different carbazole-based substitutions were synthesized to realize molecules harvesting strong blue aggregation-induced emission (AIE). Among these compounds, 1,1,2-Triphenyl-2-[9-(2-ethylhexyl)carbazol-2-yl]ethylene (3) and 1,1,2-Triphenyl-2-[9-((3-methyloxetan-3-yl)methyl)carbazol-2-yl]ethylene (4) were foun...

The synthesis and characterization of a series of electro-active compounds containing carbazolyl and indolyl moieties are reported. All the synthesized derivatives were capable of glass formation with the glass transition temperatures ranging from 89 to 130 °C. They showed high thermal stability with the 5% weight loss temperatures ranging from 370...

New stable WOLEDs based on π-extended azatrioxa[8]circulenes have been fabricated. Combining the own blue emission of the azatrioxa[8]circulenes with the yellow-green emission of the “m-MTDATA:azatrioxa[8]circulene” exciplex a broad visible region, from 400 to 700 nm, is covered. The so constructed WOLEDs exhibit luminance exceeding 23700 cd m-2 an...

Synthesis as well as thermal, optical, photophysical, and electrochemical properties of new carbazole and triphenylamine twin derivatives with high triplet energies are reported. The synthesized compounds exhibit ability of glass formation. Their glass transition temperatures are in the range of 32–37 °C. The triphenylamine and carbazole derivative...

A series of push-pull carbazole-based compounds has been experimentally and theoretically characterized in combination with the X-ray analysis of the corresponding single crystals. The introduction of the strong electron-withdrawing tricyanovinyl group in the carbazole core affords electron-transporting ability in addition to the characteristic hol...

Fluorenone-based compounds usually emit light in the yellow-red region. While different origins have been assigned to these colors, only few studies make a direct correlation between the characteristic emission and the lowest absorption energy band (LEB). Intriguingly, striking similarities can be observed in the position, shape, and intensity of t...