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The structures of J-aggregates of two monomethine dyes are compared at the meso- and nanoscale by using fluorescence and atomic force microscopy. The J-aggregates of the two dyes are found to have solely a monolayer structure and to be polymorphic. Morphologically, monolayers represent narrow skew-symmetric strips and symmetric rhombi in the case of the first and the second dyes. The second morphological type is the tubular type in both cases. For monolayers of both dyes, atomic force microscopy imaging at the ultimate resolution reveals the presence of a quasi-one-dimensional substructure consisting of densely packed nanostrips with a width in the range of 7–10 nm. The nanostrips are interpreted as building blocks emerging at early stages of monolayer crystallization that proceeds via a nonclassical multistep mechanism.

The effect of addition of J-aggregates of polymethine dye into the hole-transport layer of an organic light-emitting diode (OLED) on its characteristics and operational stability was studied. Water-soluble PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) and the interpolymer complex of polyaniline and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAn-PAMPSA) were used as the matrices of polymer nanocomposites. The highest efficiency characteristics of the OLEDs with the considered structure were achieved using PAn-PAMPSA at a particular component ratio in the interpolymer complex. Additives of J‑aggregates did not significantly affect the efficiency characteristics of the OLEDs; however, an increase in the operational stability of devices was recorded.

Estimation of the influence of molecular substituents on electroluminescence and electron–hole mobility in copolyfluorenes with the use of a CELIV technique has revealed that minor changes in the number of benzothiadiazole fragments in copolyfluorenes has a dramatic effect on the optoelectronic properties of these polymers to improve the electroluminescence and electron mobility by factors of 20 and 10, respectively.

A crystallographic analysis of the images of destruction fragments of tubular monomethine dye J-aggregates has been performed for the first time. It is shown that the formation of characteristic zigzag fragments is caused by the unwrapping of cylindrical surface on plane. Possible cleavage directions for the monolayer forming the tube walls are considered and an interrelation between the destruction products and molecular packing of this monolayer is established.

—J-aggregates of a carbocyanine dye (pyridinium salt of 3,3'-di-(γ-sulfopropyl)-4,5,4',5'-di(tieno-3'',2'')-9‑ethyl-tiatrimethine cyanine betaine) (CC) were studied via the high-resolution AFM method at the mesoscale and nanoscale. They were found to exist in two structurally different polymorphic forms of single layers and fibrils. The class of single-layer J-aggregates consists of irregular micron sheets and giant submicron tubes, whose structure is identical to tubular J-aggregates of other cyanine dyes. The fibrillar J-aggregates are composed of 3-nm-high fibrils forming the networks owing to merging and branching, as well as of “elementary” fibrils with a height close to the molecular sizes of dye. Structural models of elementary fibril with molecular “staircase” and “ladder” stacking types were proposed as well.

A new highly luminescent iridium complex, bis(2-phenylpyridine-N,C2′)[2-(2′-tosylaminophenyl)benzoxazole-N,N′]iridium(III) [Ir(ppy)2(TAPBO)] (TAPBO- 2-(2′-tosylaminophenyl)benzoxazole) has been synthesized and its molecular structure determined using single crystal X-ray diffraction analysis. The Ir(III) complex displayed intense yellow photophosphorescence emission that manifested its potential for organic electroluminescence. Photo- and electroluminescent properties of the OLEDs fabricated on the basis of [Ir(ppy)2(TAPBO)] with doping concentration of Ir(ppy)2(TAPBO) varied from 3 to 20 wt% have been investigated. The OLED with 9 wt% Ir(ppy)2(TAPBO) exhibited maximum luminance of 9000 cd m−2 at 180 mA/cm−2 and had sufficiently low turn-on voltage of ca. 6 V.

The molecular orientation in monolayer J-aggregates of 3,3-di(γ-sulfopropyl)-5,5-dichlorotiamonomethinecyanine dye has been precisely estimated using improved linear polarization measurements in the fluorescence microscope in which a multiangle set of polarization data is obtained using sample rotation. The estimated molecular orientation supplemented with the previously established crystallographic constraints based on the analysis of the well-developed two-dimensional J-aggregate shapes unambiguously indicate the staircase type of molecular arrangement for striplike J-aggregates with the staircases oriented along strips. The molecular transition dipoles are inclined at an angle of ∼25° to the strip direction, whereas the characteristic strip vertex angle ∼45° is formed by the [100] and [1-10] directions of the monoclinic unit cell. Measurements of the geometry of partially unwound tubes and their polarization properties support the model of tube formation by close-packed helical winding of flexible monolayer strips. In the tubes, the long molecular axes are oriented at a small angle in the range of 5-15° to the normal to the tube axis providing low bending energy. At a nanoscale, high-resolution atomic force microscopy imaging of J-aggregate monolayers reveals a complex quasi-one-dimensional organization.

Meso- and nanoscale structural polymorphism of monolayer J-aggregates of four cyanine dyes are investigated. Three mesoscale morphological types are observed: ribbons, rhombic leaves, and tubes. Tubes are formed during cylindrical spinning of ribbons. Lined substructure characterized by the line width of about 7 nm is found in the case of monolayers of monomethine cyanine dyes at the nanoscale.

Condensation of 2-methylbenzothiazole with 2,2′-bithiophene-5-carbaldehyde affords the title compound, a new chromophore. This compound was used for the doping of poly[9,9-bis(6-diethoxylphosphorylhexyl)fluorene], and the obtained composites demonstrated high electron mobility (1.50 × 10−4 cm2 V−1 s−1) in contrast to dopant-free matrixes.

Novel compounds—substituted indolo[3,2-b]carbazoles (SIC)—which demonstrate semiconducting properties are synthesized. Electroluminescence (EL) is studied in multilayer diode structures based on SIC. The values of hole (6.38 × 10–5 cm2/(V s)) and electron mobilities (1.31 × 10–5 cm2/(V s)) of these electroactive materials are measured. It is estimated that heteroaromatic nuclei are the electron transport centers of SIC molecules.

New copolyfluorenes containing 4,7-di-2-thienyl-2,1,3-benzothiadiazole and 2,1,3-benzothiadiazole or derivatives of naphthalimide as luminophores were synthesized under microwave heating. Charge-transporting carbazole, triphenylamine, or diphenyloxadiazole groups were introduced into the side chains of polymers through 9,9-bis-(4-phenoxy)-2,7-fluorene units. Copolyfluorenes were also modified via insertion of 10 mol% of 2,7-[9,9-bis-(6′-diethoxyphosphorylhexyl)]fluorene or dibenzothiophene-S,S-dioxide comonomer units into the polymer backbone. This study demonstrates the influence of chemical compositions, molecular masses of the polymers under investigation, and thermal treatment on microstructures of their films. Photo- and electroluminescent characteristics of the synthesized copolyfluorenes were determined. The best samples of devices manifested the luminance of 5110 cd m⁻2, the current efficiency of 1.33 cd A⁻1, and the CIE 1931 xy chromaticity coordinates of (0.339 0.364), or 7930 cd m⁻2, 2.18 cd A⁻1, and of (0.300 0.369) respectively. The effect of active layer thickness on the white emission color of polymer light-emitting diodes was revealed.

International audience; In the paper we present synthesis and characterization of new donor-acceptor thiophene derivatives (TDs) containing vinylbenzo[d]thiazole, vinylpyridine and 1H-imidazo[4,5-f][1,10]phenanthroline residues. Using CELIV method, electron and hole mobility have been studied in the polymer layers based on poly [9,9-bis(6diethoxyl-phosphorylhexyl)fluorine] (PF-EP) doped with the TDs. Polymer light-emitting diodes (PLEDs) containing newly synthesized polyfluorene (PF) as emitting layers and PF-EP/TD composites as electron transporting layers show higher brightness at 15V as compared with TD free PF-EP.

The irregular one-dimensional substructure of cyanine dye J-aggregate monolayers resolved by high-resolution atomic force microscopy is inherited from the first stages of multi-stage monolayer crystallization.

Polymorphic J-aggregates of monomethine cyanine dye 3,3'-di(γ-sulfopropyl)-5,5'-dichlorotiamonomethinecyanine (TC) have been studied by fluorescence optical microscopy (FOM) and by atomic force microscopy (AFM). The in situ FOM observations in a solution drop distinguish two J-aggregate morphology classes: flexible strips and rigid rods. The AFM imaging of dried samples reveals a strong J-aggregate structural rearrangement under adsorption on a mica surface with the strips self-folding and the rods squashing into rectangular bilayers and much deeper destruction. In the present work, the following structural conclusions have been drawn on the basis of careful consideration of strip crystal habits and various structural features of squashed/destructed rods: (1) the tubular morphology of TC rods is directly proved by FOM measurements in the solution bulk; (2) the staircase model of molecular arrangement in strips is proposed explaining the characteristic ∼44° skew angle in strip vertices; (3) a model of tube formation by a close-packed helical winding of flexible monolayer strips is proposed and justified which explains the observed J-aggregate polymorphism and strip-to-rod polymorphic transformations in a wide spatiotemporal scale; (4) at a nanoscale, an unexpectedly complex quasi-one-dimensional organization in J-aggregate two-dimensional monolayers is observed by high-resolution AFM imaging of constituent nanostrips separated by a characteristic distance in the range of 6-10 nm. The obtained results indicate that the underlying monolayer structure is the same for all J-aggregate polymorphs.

A crystallographic analysis of optical fluorescent images of two-dimensional polygonal structures of J-aggregates of 3,3′-di(γ-sulfopropyl)-5,5′-dichlorothiamonomethinecyanine (MCD) cyanine dye has been performed. In aqueous solutions, MCD forms striplike J-aggregates in the form of extended strips with parallel sides and an oblique or right-angled end. It is found that the acute angle in oblique J-aggregates has a single value close to 45°. The staircase model of molecular packing in oblique J-aggregates is proposed with a slippage angle of 25° expected from the molecular simulation. Within this model the sides of aggregates are formed by the [100] and $$[\bar 110]$$ faces, and the acute angle between them is equal to the experimentally observed angle. Right-angled rectangular J-aggregates are presumably described by the ladder model.

A new bis[2-(N-tosylamino)benzylidene-4′-dimethylaminophenylaminato]zinc complex was synthesized, its structure was studied by methods of elemental analysis, IR spectroscopy, 1H NMR spectroscopy, X-ray absorption spectroscopy, and quantum chemical calculations. Electron absorption and photoluminescence spectra of the zinc complex were investigated. An OLED device based on it was made and found to emit “soft” yellow light with CIE coordinates (x = 0.431, y = 0.537) and radiation luminance 1300 cd m−2 at a working voltage of 14 V.

New zinc and cadmium complexes with 3-[2-(N-tosylaminobenzylidene)]aminoquinoline (HL1) and 6-[2-(N-tosylaminobenzylidene)]aminoquinoline (HL2) were synthesized. The structures of HL1, HL2 and complexes ML2 (M = Zn, Cd) were established based on the elemental analysis data, IR spectroscopy, 1H NMR spectroscopy, and quantum chemical calculations. Electron absorption and photoluminescence spectra of the complexes were studied. OLED devices were developed, where ZnL2 2 complexes were used as an emission layer. This device emitted yellow light with CIE x = 0.436, y = 0.492 and x = 0.463, y = 0.484, maximum luminance at 10 V was 126 and 150 cd m−2, respectively.

2-(4′-Bromopyrazolyl-1′)-3-tosylaminopyridine (HL3) and its complex ZnL2 (I) are synthesized, and their structures are studied by IR, UV, and 1H NMR spectroscopy. The molecular structure of complex ZnL2 is determined by X-ray diffraction analysis. The atomic structure of ZnL2 is confirmed by the optimization of the molecular geometry using quantum-chemical calculations in the density functional theory approximation. The experimental bands in the absorption spectrum of complex I are interpreted on the basis of the calculations, and its photoluminescence properties are studied.

Chemical and electrochemical syntheses of zinc(II) and cadmium(II) complexes based on tetradentate Schiff bases (H2L1 and H2L2) resulting from condensation of 2-tosylaminobenzaldehyde with 3,6-dioxa-1,8-octanediamine or 4,9-dioxa-1,12-dodecanediamine were performed. The structure, composition, and properties of the complexes were studied by elemental analysis, IR, 1H NMR, and UV spectroscopy, X-ray absorption spectroscopy, and X-ray diffraction. The zinc(II) and cadmium(II) complexes luminesce in a DMF solution in the blue spectral region (λPL = 425–433 nm), the photoluminescence quantum yield φ being 0.25–0.30. Multilayer zinc(II)- and cadmium(II)-based electroluminescent structures with green-blue emission of the exciplex nature were fabricated.

New conjugated copolyfluorenes containing covalently bound quinolinolate complexes of iridium in the backbone are synthesized under conditions of the Yamamoto reaction. The structures and properties of the polymers are characterized via NMR spectroscopy, GPC, TMA, and TGA. All copolymers show solubility in common organic solvents and feature good thermal and thermo-oxidative properties. The absorption, luminescence, and electrochemical properties of the polymers are investigated. In thin films, the polymers emit blue light with wavelengths in the range 450–470 nm. The electroluminescence spectra of the copolymers show broad intense bands in the visible region with maxima at 500–525 nm corresponding to various emission colors with the chromaticity coordinates (0.361, 0.437) and (0.247, 0.411). The synthesized iridium-containing copolyfluorenes may be used as electron-hole transport materials in light-emitting diodes.

New copolyfluorenes containing covalently bound iridium β-diketonate complexes (featuring high values of phosphorescence efficiency) in the backbone are synthesized through the targeted selection of molar ratios of monomers containing functional groups responsible for various irradiation regions under conditions of the Yamamoto reaction. All copolymers show solubility in organic solvents, such as DMF, DMAA, DMSO, toluene, THF, and chloroform, and feature reversible redox electrochemical properties. The electroluminescence spectra of the copolymers show broad intense bands in the visible region with maxima at 482–538 nm and a maximum brightness of 320 cd/m2 at a current density of 2900 A/m2. The iridium-containing copolyfluorenes are of interest as effective electroluminescent materials for light-emitting diodes.

New copolyfluorenes containing units of 4,7-dibromo-2,1,3-benzothiadiazole (green luminophore) and 3,6- or 2,7-dibromocarbazole derivatives with side-chain fragments of green (4-pyrrolidinyl-1,8-naphthalimide) and red (Nile red) luminophores and additional carbazole or diphenyloxadiazole groups are synthesized via the Suzuki copolycondensation reaction. The structure of the polymers is modified via insertion of triphenylamine, aryloxadiazole, and quinoxaline units in the backbone of copolyfluorenes and via introduction of triphenylamine, fluorene, and benzene terminal groups. The molecular-weight characteristics of the polycondensation products and the specific features of the transfer of polyfluorene emission energy to the indicated luminophores in solutions and films are studied. Coating the emissive copolyfluorene layer with electron-conducting and hole-blocking layers of poly[9,9-bis(6′-diethoxyphosphorylhexyl)fluorene] makes it possible to increase the brightness of light-emitting diodes (to 2380–3900 cd/m2) and their current and luminance efficiencies.

Complexes M(NpOON) n and M(NpSON) n (NpOON = 3-(2-benzoxazol-2-yl)-2-naphtholate, NpSON = 3-(2-benzothiazol-2-yl)-2-naphtholate, M = Li, Sc, Sm, Eu, Gd, Tb, Dy) were prepared by the reactions of silylamides M[N(SiMe 3 ) 2 ] n ( n = 1, 3) with corresponding O,N-chelating ligand. For the synthesis of zinc complexes Zn(NpOON) 2 and Zn(NpSON) 2 diethylzinc was used. Li, Zn and Sc naphtholates exhibited strong green electroluminescence. The OLED device based on Sc(NpOON) 3 showed luminance 8780 cd/m 2 (12 V) – the highest value among the devices prepared with organoscandium luminophores.

A new monomer, the dibromo derivative of fluoranthene 1-[7,10-bis(4-bromophenyl)fluoranthen-8-yl]pyrene, is synthesized and used to prepare three new copolyfluorenes containing 3, 5, and 10 mol % 7,8,10-triarylfluoranthene groups via the Yamamoto reaction. The number-average molecular masses and polydispersities of the polymers vary in ranges 41900–78900 and 2.7–3.5, respectively. All polymers are soluble in common organic solvents, and their glass-transition temperatures are from 95 to 115°C. Temperatures corresponding to a 10% loss in weight during heating in argon and air are in the ranges 420–435 and 405–415°C, respectively. The photoluminescence spectra of the polymers exhibit strong blue emission with a maximum at 418 nm, whereas the absorption spectra show characteristic peaks at 351–357 nm. All polymers possess reversible or partially reversible redox behavior owing to high electric activity and demonstrate redox pairs at 1.51 eV (oxidation) and −2.09 eV (reduction).

Subangstrom accuracy AFM height measurements and high-resolution visualization of crystallographic habits enabled us to give an insight into how stacked dye molecules are arranged in J-aggregate monolayers of 3,3′-di(γ-sulfopropyl)-4,4′,5,5′-dibenzo-9-ethylthiacarbocyanine betaine pyridinium. Ladder and staircase molecular arrangements were self-consistently proposed for the explanation of the stripe-like and leaf-like J-aggregate polymorphism correspondingly. It is inferred that a J-aggregate building unit constitutes a symmetric monolayer of ∼1.35 nm in a height that consists of all-trans monomers with anti-parallel up-down orientation and a slip angle of ∼15 ° . As it follows from AFM images of folded/overlapped J-aggregates, these species manifest themselves as mechanically very flexible structures.

A number of new phenylated polyfluorenes with blue emission are synthesized via the Diels-Alder reaction in chloronaphthalene and supercritical carbon dioxide. It is shown that these polymers are thermally stable. A comparative analysis of their properties shows that a “green” solvent is a suitable alternative to organic solvents for obtaining phenyl-substituted polyfluorenes via the Diels-Alder reaction.

Atomic force microscopy was used for the study of two-dimensional J-aggregates monolayer structures of two cyanine dyes with a high-resolution. Two coexisting morphologically different types (i.e. the bilayer rectangular stripes and monolayer curve shaped leaves) were observed for 3,3’-di(γ-sulfopropyl)-4,4’,5,5’-dibenzo-9-ethylthiacarbocyanine betaine pyridinium (dye D-1). The morphological diversity, the crystallographic peculiarities and the monolayer height ~ 1.35 nm are selfconsistently explained by the difference in the molecular packing arrangements, i.e. the ladder for stripes and the staircase for leaves. A building unit of both J-aggregate types is a symmetric monolayer with the same height and slip angle ~ 15o, composed of all-trans monomers with anti-parallel up-down orientation. For the two-dimensional sheets of the second cyanine dye (5,5'-dichloro-3,3'-disulfopropyl thiacyanine sodium salt) Dye-2 the fine substructure formed by close packed parallel narrow threads was resolved. The stripes were inclined at the angle ~30o to the J-aggregates long side providing for the first time the direct microscopic support for the probable staircase molecular arrangement. It is speculated that the quazi-one-dimensional staircase-type and ladder-type units are building blocks of the two-dimensional aggregates of various cyanine dyes.

New π-conjugated copolyfluorenes carrying main-chain electron-acceptor triazole groups and side-chain electron-donor carbazole fragments are synthesized. All copolymers show solubility in common organic solvents and exhibit high thermal stability and excellent film-forming behavior. The absorption, photoluminescent, electroluminescent, and electrochromic properties of the copolymers are investigated. Polymer films feature stable electrochromic properties as their color changes from yellow in the neutral from to lilac in the oxidized form during a change in the applied voltage from 0 to 1.9 V. In addition, copolyfluorenes demonstrate better electroluminescent properties than the standard homopolylfluorene and offer promise as attractive electroactive materials for use as emitting layers in polymer light-emitting devices.

Experimental data on electroluminescence of new light emitting materials, semiconducting organic polymers doped with nanosized J-aggregates of cyanine dyes, are described. OLED structures are considered. New light-emitting diode structures are developed. Polyaniline electroluminescence band is observed. High-resolution atomic force microscopy (AFM) is used to study J-aggregate structures. The AFM procedure is improved to increase accuracy in determination of J-aggregate dimensions. Certain supramolecular species are long ribbons with high flexibility.

Experimental data on electroluminescence of new light emitting materials, semiconducting organic polymers doped with nanosized J-aggregates of cyanine dyes, are described. OLED structures are considered. New light-emitting diode structures are developed. Polyaniline electroluminescence band is observed. High-resolution atomic force microscopy (AFM) is used to study J-aggregate structures. The AFM procedure is improved to increase accuracy in determination of J-aggregate dimensions. Certain supramolecular species are long ribbons with high flexibility.

Atomic force microscopy (AFM) was used to obtain high-resolution images of nanosized organic J-aggregate molecular crystals of 3,3′-di(gamma-sulfopropyl)-5,5-dichlorotiamonomethinecyanine (TC) and 3,3′-bis(2-sulfopropyl)-5,5′,6,6′-tetrachloro-1,1′-dioctylbenzimidacarbocyanine (C8S3) and precise height measurements of J-aggregates monolayers were conducted. It was found that TC J-aggregates obtained both in the solution bulk and by self-assembly on the mica surface are extended monolayer sheets of high mechanical flexibility. The height of TC is 1.05 ± 0.05 nm, which corresponds to the crystallographic size of a single molecule along the short axis. A model of asymmetric single-layer molecular packing is suggested in which sulfopropyl groups are located on the same side of the layer plane. In the case of C8S3, narrow multilayer ribbonlike structures with heights of 3 to 30 nm were observed. The heights are strictly quantized with a step of 3 nm. A bilayer model of C8S3 molecular packing in J-aggregates is discussed with partially interpenetrating monolayers with hydrophobic sides oriented face to face. A model of structural C8S3 units as “elementary ribbons” with the transverse dimensions of 3 × 4 nm is suggested on the basis of the comparison of AFM data with electron microscopy data from other works.

39 In recent time, conjugated electroluminescent polymers have attracted much attention from both the scientific and practical viewpoint due to their application as electroactive materials for light emitting diodes [1–3]. It has been found that intense electroluminescence (EL) in polymer requires high electron–hole conduction of a medium related to the mobility of charge carriers and a balance of injection of carriers of both signs from opposite electrodes into the emission poly meric layer. However, the majority of EL polymers are hole transport materials, which leads to the imbalance of charge injection and a poor quantum yield. A search for new efficient electron transport polymers is required to improve performance of electrooptical devices, which is achieved in particu lar by introducing into macromolecules electron withdrawing fragments: triazole [4], oxadiazole [5], quinoline [6], and quinoxaline [7]. The latter is the least studied. One can suppose that polyphenylqui noxalines (PPQs) will show higher electron with drawing properties owing to the presence of four electron withdrawing heteroatoms. A promising approach to improve the quantum yield is provided not only by the balance of the electron and hole conduction but also by design of multilayer bipolar (donor–acceptor) emission polymers. In this work, to solve this problem, we have used a combination of carbazole and quinoxaline contain ing fragments in PPQ macromolecules. Such mole cules are known to show high thermal and oxidative stability, good mechanical and film forming proper ties, and solubility in organic solvents [8]. In continu ation of our studies [9–11], we have prepared and studied novel bipolar carbazole containing PPQs as efficient electron–hole and transport materials; for this purpose, we obtained previously unknown bis(α diketone) III. A common method for the synthesis of bis(α diketone)s is the oxidation of bis(phenylethy nyl)arenes obtainable from aromatic dibromides and arylacetylene. We have proposed a new method for the synthesis of bis(α diketone) III by the nucleophilic substitution reaction of fluorodiketone II, already containing bis(α dicarbonyl) groups, with dicarbazole I accord ing to Scheme 1. CHEMISTRY

Atomic force microscopy (AFM) was used for the morphological characterization and precise height meas-urements of two-dimensional molecular layers of carbocyanine dye 3,3’-di(r-sulfopropyl)-4,4’,5,5’-dibenzo-9-ethylthiacarbocyanine betaine pyridinium salt. The AFM measurements reveal three morphological types of molecular aggregates: leaves, stripes and spots. The leaves are stripes have same monolayer height ~1.4 nm and different crystal shapes: the leaves are monoloyers with the lens shape and the stripes are bilay-ers with the shape of extended rectangles. The monolayer height ~1.4 nm was interpreted as indicating the symmetrical packing arrangement of dye molecules. In the symmetrical monolayer, the sulfopropyl groups of all-trans monomer units are located on both monolayer sides whereas the adjacent stacked dye molecules have a lateral slippage providing the J-aggregate optical properties. The lower height of spots ~1 nm was explained by the model of an asymmetric monolayer with sulfopropyl groups of all-trans monomers occupy-ing the same position with respect to the monolayer plane. The packing arrangement of all-trans monomers in the asymmetric monolayer corresponds to H-aggregate. The alternative models of the packing arrange-ment in monolayers with mono-cis1 monomer configuration are discussed.

A new fluorene-containing bis(cyclopentadienone) is synthesized. The interaction of this compound with various diethynylarylenes via the Diels-Alder reaction gives rise to new photoactive phenylated polyfluorenes that emit blue light. Absorption and fluorescence maxima are observed at 330–359 and 394–426 nm, respectively. Polymers show good solubility in organic solvents and possess high chemical resistance and thermal stability.

Nanostructured polymer materials doped by molecular aggregates and chromophores; the mechanism of electron conductivity in these systems; the effects of a combination of conductivity with optical, photophysical, emissive properties of thin-film polymer systems; and various devices on the basis of these properties and effects and discussed.

It is found that one of the types of molecular organic nanocrystals, the so-called J-aggregates, is able to modify optoelectronic properties of electroactive polymers. It is intrinsic that the polyaniline interpolymeric complex, known as p-type semiconductor, turns into electroluminescent material in the presence of J-aggregates of 3,3-di(gamma-sulfopropyl)-5,5-dichlorotiamonomethincyanine triethylammonium salt. During the studying of new organic light-emitting diode structures, in which the polyaniline/J-aggregates polymeric composite forms both recombination and emitting layers, a polyaniline intrinsic electroluminescence spectrum is obtained. The electroluminescence band completely coincides with the polyaniline photoluminescence spectrum; it has maximum at 400 nm. The electroluminescence mechanism in the studied nanocomposites is discussed.

New bis(α-diketones) with thiophene and benzothiophene moieties were synthesized. A series of new polyphenylquinoxalines containing these moieties in side chains was prepared via polycondensation of these diketones with different aromatic tetramines. The polymers are soluble in a variety of organic solvents, and their solutions form transparent films having a tensile strength of σ = 80–100 MPa and an elongation at break of ɛ = 5–12%. The polymers exhibit fluorescence in solution in trifluoroacetic acid and in films with a maximum at 430–570 and 460–480 nm. The 10% mass loss temperature in air ranges within 440–490°C.

New bis(α-diketones) containing thiophene and dibenzothiophene groups were synthesized. Via the reaction of these monomers with aromatic tetramines under high-temperature polycondensation conditions, a series of new polyphenylquinoxalines combining high thermal and mechanical characteristics with solubility in organic solvents were prepared. Polyphenylquinoxalines exhibit intense fluorescence in solution and in thin films with maxima in the region of 432–522 and 450–530 nm in the case of thiophene-containing and dibenzothiophene derivatives, respectively.

New carbazole-containing polyphenylquinoxalines combining the electron-transport behavior of quinoxaline with hole-transport and electroluminescent properties of carbazole have been synthesized. The polymers show solubility in organic solvents. Their glass transition temperatures range from 315 to 370°C, and temperatures corresponding to 10% weight loss vary from 510 to 560°C (in air). It has been demonstrated that these polymers exhibit electroluminescent behavior in the 450–750 nm spectral region and offer promise as emitting and electron-hole transport materials for polymeric light-emitting diodes.

The mechanism of electroluminescence in polymeric thin-layer devices based on aromatic polyimides and various molecular complexes of Pt porphyrins as heavy-atom-containing luminophores was studied. On the basis of spectral and electron-hole transport properties of aromatic polyimides and Pt porphyrins, as well as the current concepts adopted in polymer photonics, the processes of singlet-singlet and triplet-triplet energy transfer in the examined single-layer systems aromatic PI-Pt porphyrin with a high electrophosphorescence quantum yield exceeding 2% are discussed.

Electroluminescent polymeric nanocomposite structures that are based on aromatic polyimides and cyanine dye nanosized crystals known as J aggregates and emit light in the IR region were prepared. For the first time, doped polymer systems were found to display IR luminescence whose spectrum had the form of a very narrow band that peaked at 1100 nm. Nanosized J-aggregate crystals in these new polymer materials act not only as effective acceptors of energy of excitonic states but also as active electron-hole transport sites.

Electroluminescence in polymer nanocomposite structures with electron–hole transport, called J-aggregates, which are based on aromatic polyimides and nanosized crystals of cyanine dyes, is studied. In the near-IR range, the electroluminescence with a narrow emission spectrum (with a maximum at 815 nm) is observed for the first time. It is shown that not only are the organic nanosized crystals of the J-aggregates effective acceptors of the exciton state energy, but they play the role of active electron–hole transport centers in these novel polyfunctional polymer materials.

Study of electron and hole mobility for 5,11-dihexyl-6,12-di(2-thienyl)indolo[3,2- b ]carbazoles has shown that their heteroaromatic cores act as electron transport centers.

The electroluminescence of J-aggregates was detected in polymer systems doped with cyanine dye molecules. J-aggregate/polymer composites exhibiting intense absorption band with a maximum in the red range were developed on the base of polyimides and a copolymer formed from phenylacetylene and 4-methylcoumarin-4-pentynoate. Efficient electrolumunescence was revealed in these systems. It was found out that J-aggregates play an active role in charge carrier transport in the composite materials.