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The effect of additives of sensitizing Zn(II) and Co(II) complexes with 5,15-(diethoxyphosphoryl)-10,20-diphenylporphyrin on the mobility of holes in thin poly3-hexylthiophene films is studied. The charge carrier mobility is measured using the CELIV and photo-CELIV methods. It is found that the sensitizing additive does not affect the mobility of the equilibrium charge carriers, but causes a decrease in the mobility of the nonequilibrium charge carriers.

Electrically conductive layers prepared by the inkjet printing method with the use of an ink on the basis of the electrically conductive poly(3,4-ethylenedioxythiophene) and carbon nanoparticles were studied. The physicochemical properties of the ink components were considered. The dependence of the electrical conductivity was measured as a function of temperature and time of formation of a dry layer.

The synthesis, structure and spectroscopic properties of luminescent Zn(II) complex containing 4-methyl-N-[2-[(E)-pyridinylmethyl]phenyl]benzosulfimide ligand are described. The Zn(II) complex was characterized by single-crystal X-ray diffraction study. Time-dependent density functional theory calculations at the B3LYP/6-31G∗ level were performed on Zn(II) complex to interpretation its experimental UV–Vis absorption spectrum. OLED device with Zn(II) complex as light-emitting layer has been fabricated. The electroluminescent spectrum of OLED showed a dominant yellow emission at 525 nm (Commission Internationale de l’eclairage (CIE) coordinates x = 0.409 and y = 0.506) and a weak shoulder at 650 nm without any other distinguishing emission from host or adjacent layers. The fabricated OLED generated luminance of more than 1000 cd/m2 at 16 V, current density 600 mA/cm2 and rather low turn-on voltage of ca. 4 V and power efficiency 1 lm/W.

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.

The third-order susceptibility of vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymer are analyzed by using the z-scan technique with a nanosecond laser as an excitation source. It is established that optical transmittance of the VDF-TrFE samples decreases after their polarization in an electric field.

A rapid progress in the development of solar cells based on hybrid organic-inorganic perovskites CH3NH3PbI3 (MAPbI3) is observed in recent years, and power conversion efficiency as high as 22.1 % has been reported. However, a low stability is the main drawback of these materials, which impedes their practical use for solar energy conversion. This work is devoted to the synthesis of CH3NH3PbI3 films from CH3NH3I and PbI2 precursors and spectroscopic investigation of their stability under high-intensity laser illumination.

Organometal triiodide perovskites are promising, high-performance absorbers in solar cells. Considering the perovskite as a thin film absorber, we solve transport equations and analyse the efficiency of a simple heterojunction configuration as a function of electron–hole diffusion lengths. We found that for a thin film thickness of ≃1 μm the maximum efficiency of ≃31% could be achieved at the diffusion length of ∼100 μm.

Polyaniline (PANI) films were prepared by electrochemical polymerization of aniline on Pt-electrode in aqueous medium in the presence of polymeric sulfonic acids distinguished by different flexibility of the polymer chain: (1) poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA, flexible chain); (2) poly(4-styrenesulfonic acid) (PSSA, flexible chain), (3) poly-4,4′-(2,2′-disulfoacid)-diphenylene-iso-phthalamide (i-PASA, semi-rigid chain); and (4) poly-4,4′-(2,2′-disulfoacid)-diphelylene-tere-phthalamide (t-PASA, rigid chain). Raman spectroelectrochemical studies using 532 nm laser excitation were carried out in aqueous HCl. The conventional HCl-doped PANI films were also studied for comparison. The results allowed one to distinguish the potential-dependent vibrations belonging to PANI and potential-independent vibrations belonging to the polyacids. In addition, amide C=O vibration was separated in the spectra by comparing the results for amide-containing (PAMPSA, i-PASA, and t-PASA) and amide-free (PSSA) PANI-polyacid complexes. The films of PANI-polyacid complexes demonstrated increased content of radical cation moieties at low potentials compared to PANI–HCl films.

Poly(3,4-ethylenedioxythiophene) (PEDOT) films were electrodeposited in galvanostatic mode in the presence of salt or acid forms of sulfonated polyelectrolytes distinguished by different rigidity of the polymer main chain and presence of amid fragments in their stricture. The films obtained were characterized by cyclic voltammetry, as well as Ultraviolet-Visible-Near Infrared and Raman spectroelectrochemistry at fixed potentials in non-aqueous and aqueous media, respectively. It was found that bipolaronic fragments of PEDOT are hardly to be formed at high anodic potentials in the films prepared in the presence of acid forms of the rigid-chain amid-containing polyelectrolytes as distinct from all other polyelectrolytes regardless of amide-groups content. In situ Raman studies during PEDOT electrodeposition in the presence of the acid forms of the rigid-chain amid-containing polyelectrolytes showed domination and retarded delocalization of radical cations being the moving force of the electropolymerization. The results are discussed in terms of possibility/impossibility of proton-transfer inter- and intra-molecular interactions between sulfonic and amid groups in the polyelectrolytes. These result in the appearance of positive charges (confirmed by ζ-potential measurements) on the polyelectrolyte chain, which create barriers for radical cations delocalization, their recombination into bipolarons, as well as prevents growth of long PEDOT chains. The prepared materials were studied as a hole-transport (buffer) layer in organic photovoltaic cells. The influence of polyelectrolyte structure on the cells performance is discussed.

The electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of the salt and acid forms of polymer sulfonates with different polymer-chain flexibility is studied. The dependence of the rate of synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) on the nature of polysulfonate counterion that determines the type and distribution density of the charge in the polyelectrolyte chain is demonstrated. For the Н+ form of a rigid-chain polysulfonate, it is found that the specific interactions between parts of its macromolecules lead to destabilization of EDOT•+ radical cations, hinder the growth of PEDOT chains, and favor the formation of structures with the high degree of charge localization.

Conditions that allow obtaining stable aqueous dispersions based on conducting polymer, polyaniline, as a result of aniline polymerization in the solution of polymeric acid at its twofold excess were determined. The electrical and optical properties of polianiline obtained under these conditions remain invariable during at least 2 years due to the absence of aggregation of conducting polymer particles that are separated by macromolecules of polymeric acid. Data obtained by EPR spectroscopy, SEM, UV–visible spectroscopy, and IR spectroscopy prove these results.

The structure of compounds with the perovskite structure ABX3 (A and B are cations, X are anions O2—, F—, Cl—, Br—, and I—), which are widely used in engineering due to unique electrical, optical, and photovoltaic properties, has been considered. Hybrid organic—inorganic halide perovskites important for photovoltaics of a new generation are worth mentioning; they contain cations of organic nitrogen bases as monovalent cations. A molecular dynamics (MD) study of the CaTiO3 base structure (Ca2+, Ti4+, and O2—) has been performed in order to develop the methodology of computer simulation and optimization of the shape and parameters of atomic potentials for perovskite systems.

Composites with photoelectrical, nonlinear optical, and photorefractive properties have been prepared. The composites consist of polyvinyl alcohol, single-wall carbon nanotubes, and fullerene C60. Addition of C60 with a long wavelength boundary near 630 nm resulted in an eight- to tenfold increase in both the quantum efficiency of generation of mobile hole charges and the photorefractive two beam gain coefficient measured at wavelengths exceeding 1000 nm (over an area of optical absorption of nanotubes). This is attributed to electron trapping by acceptor fullerene, which limits the regeneration of photogenerated charges and provides an increase in mobile hole charges.

Adsorption of influenza A viruses and their antibodies on golden surfaces, thin films of polyaniline and polyaniline complex with polysulfonic acids, has been studied. The composition of interpolymer complexes was found to influence both the surface relief of synthesized films and the adsorption efficiency. Moreover, it has been shown that the adsorption of bio-objects increased with a growth of surface roughness of the polymer coatings. It has been suggested that this effect was caused by an tight contact between the studied bioobjects and the surface relief elements of close size. In addition, the surface protuberances can act as active centers of adsorption due to their larger accessibility. The results testify to the potential of application of films composed of interpolymer polyaniline complexes with a developed surface relief as a basis to prepare biosensors that are sensitive to viruses and antibodies.

The present study is aimed to elucidate main structural features of polymeric sulfonic acids (the rigidity of main chain, the distance between sulfonic groups on the chain, the hydrophobicity of main chain or side fragments) on the course of 3,4-ethylenedioxythiophene (EDOT) electropolymerization and electronic and chemical structure of the poly(3,4-ethylenedioxythiophene) (PEDOT) films obtained. The films were prepared by electrochemical polymerization in cyclic voltammetry, potentiostatic, and galvanostatic regimes in aqueous solutions of different polyacids in the absence of supporting electrolyte. The effect of the chemical structure of polyacid on the course and rate of PEDOT synthesis was traced by electrochemical and in situ UV-Vis spectroscopic methods. It was shown that the highest rate of EDOT electropolymerization is achieved in the presence of flexible-chain polyacid having hydrophobic fragments (groups) in its structure, followed by hydrophobic rigid-chain polyacids. The lowest rate was observed in the presence of hydrophilic flexible-chain polyacid. The electronic and chemical structure of the PEDOT films obtained was studied by in situ UV-Vis-NIR and Raman spectroelectrochemistry. The films prepared in the presence of rigid-chain polyacids at high anodic potentials demonstrate decreased content of bipolaronic fragments in their structure, while PEDOT complexes with flexible-chain polyacids are very much like conventional polymer prepared in non-aqueous medium. The results are discussed in terms of conformational state (ability to form coils and thus concentrate the monomer) of different polyacids in aqueous solution and hydrophobic interactions between the polyacids and EDOT.

The optical and photoelectric properties of present-day photosensitive polymers are of particular interest due to their prospects for use in various photoelectric applications. Here the absorption edge is studied by the constant photocurrent method which is widely used for studies of inorganic materials. For the objects to be studied, PCDTBT and PTB7 polymers and their mixtures with the PC71BM fullerene derivative are chosen. The spectral dependences of the absorption coefficient for the pure polymers and mixtures are approximated on the assumption of the Gaussian distribution of the density of states in the bands of the components, which provides a means for estimating the electrical band gaps. In addition, such processing of the spectra makes it possible to confirm some important inferences about the states responsible for optical transitions in the low-energy absorption region.

Composites of polymers with conjugated chain structures, polyaniline and polypyrrole, are used as sorbents for human and bird flu viruses. Sorption properties of the composites are compared to characteristics of the initial polymers. It is shown that polymer composites containing metallic silver nanoparticles possess sorption activity, similarly to their composites with polyethylene and the initial polyaniline and polypyrrole. The introduction of silver into polypyrrole resulted in an enhancement of the sorption activity as compared to that of the initial polymer. Nontoxic metal—polymer composites reduce considerably the concentrations of human flu viruses A(H1N1), A(H3N2), and B and bird flu virus A(H5N2) with different structures of surface virion proteins in aqueous media at a sorbent concentration of 10–20 mg/mL in the temperature range from +4 to 37°C.

Nanocomposites based on graphene and polyaniline–polyacid complexes with tunable electrical conductivity are elaborated. An influence of graphene oxidation degree on conductivity of the nanocomposites is investigated. The change of optical and electrical properties after graphene introduction into polyaniline–polyacid complexes is explained by the formation of graphene nanostacks of different size and their different distribution in the film bulk. The role of (i) internal interactions between graphene sheets revealed by high-resolution TEM and AFM and (ii) external interactions between graphene and polyaniline or polyacid of different hydrophobicity elucidated by UV–vis, FTIR-spectroscopies and pH-measurements is discussed. In case of uniform distributed graphene sheets having a low oxidation degree, the electrical conductivity of the nanocomposites based on polyaniline complexed with more hydrophilic polyacid increases up to 20 times in respect to initial polyaniline complex.

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.

Chemical polymerization of 3,4-ethylenedioxythiophene is carried out in the presence of polymeric sulfonic acids of different structures, such as flexible-chain polyacids with a uniform distribution of sulfonic acid groups along the macromolecular chain, namely, polystyrene sulfonic (PSSA) and poly-2-acrylamido-2-methyl-1-propanesulfonic (PAMPSA) acids, and rigid-chain polysulfonic acid with a nonuniform distribution of sulfonic acid groups along the macromolecular chain—namely, poly-p,p′-(2,2′-disulfonic acid)-diphenylene terephthalamide. The polymerization process and the properties of solutions and films of the synthesized complexes of poly-3,4-ethylenedioxythiophene (PEDOT) with the above polyacids are studied by the UV, visible, and near-IR spectroscopy. The electric properties of the films are investigated. The effects of the concentration ratio between the oxidizer and monomer and of the structure of polymeric acid on the kinetics of the PEDOT synthesis, as well as on the spectral and electric properties of the obtained polymer, are revealed. A correlation between the absorption of the PEDOT/PSSA complexes in the near-IR range and their specific conductivity is established.

Electrodeposition of polyaniline (PANI) complexes with a polymeric sulfonic acid of variable molecular weight has been studied with the purpose to explain specific features of aniline electropolymerization in the presence of polyelectrolytes. Poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) was taken as a model polyelectrolyte due to the ease of varying its molecular weight during polymerization of the monomer. Depending on the polyacid molecular weight, crucial changes in the shape of charge– and potential–time dependences and cyclic voltammograms have been observed during potentiostatic, galvanostatic, and cyclic voltammetry syntheses of PANI, respectively. The results are considered in terms of the influence of molecular weight on proton condensation ability of the polyacid and, therefore, on the degree of aniline protonation and its local concentration in the vicinity of polyacid macromolecule. The PANI films obtained are characterized by cyclic voltammetry and UV–vis and Raman spectroelectrochemistry, and the influence of the polyacid molecular weight on these properties is discussed.

The photovoltaic properties and the bulk photovoltaic effect have been studied in a polyvinylidene difluoride–trifluoroethylene polymeric ferroelectric doped by single-walled nanotubes and a ruthenium-based dye. The dopants serve as spectral sensibilizers that improve sensitivity to 532-nm laser radiation.

Ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated molecules of pyrazine [(15C5)4Pc]Ru(pyz)2 (1) was synthesized from a carbonyl complex [(15C5)4Pc]Ru(CO)(MeOH) (2), and the structure of the solvate complex (1)·6CHCl3 was revealed using the single crystal X-ray diffraction method. Analysis of the crystal packing showed that the weak intermolecular interactions, such as CH⋯π, CH⋯N, CH⋯O and CH⋯Cl, played an essential role in the formation of stable assemblies and their organization within the crystals. The interplay between the intramolecular axial coordinated pyrazine contacts and the weak intermolecular interactions of solvate molecules with crown-ether fragments provided the basis for rationalizing the observed self-assembly of molecules in solutions of tetrachloroethane and polymeric composites with polyvinylcarbazole. The self-assembly was investigated using UV-Vis spectroscopy, dynamic light scattering measurements, atomic force microscopy and transmission electron microscopy techniques. The formation of nanoparticles of complex (1) from a tetrachloroethane solution after three cycles of heating to 70 °C/cooling to 5 °C and two days storage was proved. Thin films (7 μm) of polymeric composites with polyvinylcarbazole prepared from a solution containing nanoparticles exhibited a nonlinear optical response measured by the Z-scan technique with application of femtosecond (1030 nm) and nanosecond (1064 nm) pulse lasers. The measured third-order susceptibility (χ(3)) of the polyvinylcarbazole composite with 4 wt% of complex (1) was equal to 1.94 × 10−10 esu, while the same composite prepared without the previously described special treatment had zero susceptibility. This result proves the essential role of self-assembly in future development of nonlinear optical materials.

Organometal triiodide perovskites are promising, high-performance absorbers in solar cells. Considering the perovskite as a thin film absorber, we solve transport equations and analyse the efficiency of a simple heterojunction configuration as a function of electron-hole diffusion lengths. We found that for a thin film thickness of ≃1 μm the maximum efficiency of ≃31% could be achieved at the diffusion length of ∼100 μm.

The nucleation of the solid phase of interpolymer complexes of polyaniline (PAn) during electropolymerization of aniline on highly orientated pyrolytic graphite in aqueous solutions of hydrochloric acid and polymer sulfoacids, which differ in the rigidity of the polymer framework, was studied in situ by atomic force microscopy. The rigidity of the polyacid chain, which determines possible changes in its conformation in solution and its ability to adapt its conformation to that of the rigid conjugated PAn macromolecule, directly affects the shape and growth rate of the nuclei of solid phase of PAn and the film morphology at the early stages of electropolymerization. The rigid-chain and semirigid-chain polymer acids, which have the conformation of an elongated or slightly bent rod in solution, determine the conformation of the interpolymer complex nuclei. In contrast, in the presence of flexible-chain polyacids, the process is mainly controlled by the conformation of PAn macromolecules.

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.

Two techniques of manufacturing a nanocomposite based on a complex of polyaniline with polymer acid and graphene are proposed. The electric conductivity of thin nanocomposite layers is higher than that of a polymer complex of polyaniline and strongly depends on the degree of oxidation of graphene. An explanation of the effect is suggested that takes into account electron interactions between the graphene planes and polyaniline backbone, as well as the possibility of formation of hydrogen bonds between functional groups of semioxidized graphene and polyacid. The results of surface topography analysis for thin layers of polyaniline and nanocomposite agree well with the regularities of the structure of each layer that are due to the above interactions between graphene and the polymer complex.

The photorefractive effect is demonstrated for the first time for the composite consisting of a ferroelectric material (polyvinylidenefluoride-trifluoroethylene) and single-walled carbon nanotubes that serve as nonlinear optical chromophores and, simultaneously, spectral sensitizers for the laser radiation with a wavelength of 1064 nm. It is demonstrated that the internal field in the ferroelectric material makes it possible to measure the photorefractive effect in the absence of the external field.

Photoelectric, nonlinear optical, and photorefractive properties of hybrid composite materials based on polyvinylcarbazole (PVK) and indium(III) 2,3,9,10,16,17,23,24-tetra(15-crown-5)phthalocyaninate [(15C5)4Pc]In(OH) are studied in detail. Field dependence of the quantum efficiency in a 7.8 μm-thick layer containing 5 at % [(15C5)4Pc]In(OH) is measured. The best approximation of the quantum efficiency with Onsager’s equation corresponds to a quantum yield of thermalized electron-hole pairs φ0 = 0.01 at initial separation r 0 = 9.8 A. Z-scan measurements in a nanosecond range showed that the electric susceptibility of [(15C5)4Pc]In(OH) solution in tetrachloroethane (TCE) with a concentration of 7 × 10−4 mol/L is χ(3) = 1.34 × 10−9 esu. The maximum coupling gain coefficient found for the material composed of PVK and 5 wt % [(15C5)4Pc]In(OH) at an electric-field intensity of 200 V/μm is Γ = 80 cm−1, and the difference between the coupling gain and absorption coefficients is Γ − α = 70 cm−1. The dependence of the coupling gain coefficient on the intensity ratio of interfering beams 1 and 2 (β = I 1(0)/I 2(0)) in a composite containing 3 wt % [(15C5)4Pc]In(OH) is measured. An increase in β was attained by decreasing intensity of the signal beam I 2(0) at constant intensity of the pump beam I 1(0) = 0.15 W/cm2 and E 0 = 214 V/μm. Within the initial segment of the curve, the coupling gain coefficient increases from 30 to 60 cm−1; then, the coefficient drops almost to the initial value. The data obtained show that the composite materials studied can be used in practice for correcting faded images. The combined analysis of the results obtained and similar data for gallium and ruthenium tetra-15-crown-5-phthalocyaninate complexes revealed the regularities in the change of the quantum yield of thermalized electron-hole pairs and the photorefractive coupling gain coefficient in a series of complexing metals: gallium(III), ruthenium(II), and indium(III). An increase in the molecular weight of the central metal atom is found to result in a substantial decrease in Γ and φ0 due to the increase in the spin-orbit coupling constant.

Feasibility has been demonstrated for the use of the interpolymer complex of polyaniline with poly(2-acrylamide-2-methyl-1-propanesulfonic acid) (PAni·PAMPSA) and its nanocomposite with partially oxidized graphene (PAni·PAMPSA/POGr) as a material for hole transport layers in the manufacture of polymer light-emitting diodes (PLED). A study was carried out on the functional characteristics of such PLED, which were compared with those of traditional PLED made with poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate anions (PEDOT/PSS). The PLED made with PAni·PAMPSA/POGr nanocomposites were shown to have better functional characteristics, namely, current density, brightness, current and luminous efficiency, than for the analogous heterostructures derived from the pure PAni·PAMPSA interpolymer complex. The PAni·PAMPSA/POGr nanocomposite may be used instead of PEDOT/PSS in the manufacture of efficient organic optoelectronic devices.

The nonlinear optical properties of solutions of (2,3,9,10,16,17,23,24-tetra-15-crown-5-phthalocyaninato)indium(III) [(15C5)4Pc]In(OH) in tetrachloroethane (TCE) have been studied by the z-scan method. It has been found that a nonlinear optical response is due to supramolecular associates formed in a tetrachloroethane solution by heating to 90°C/slow cooling to room temperature cycling. The formation of the supramolecular associates has been studied by atomic force microscopy (AFM) and electronic absorption spectroscopy (EAS). It has been shown that a single thermal treatment of [(15C5)4Pc]In(OH) solutions in TCE results in the predominant formation of dimers, as evidenced by both a short-wavelength shift of the Q-absorption band of the monomeric complex (λmax = 692 nm) to the band of λmax = 653 nm and height doubling of molecular entities as measured by AFM. The dimers are responsible for the two-photon absorption measured in the femtosecond range, which has a relatively high cross section of σ2 = 1.38 × 10−46 cm4 s/(molecule, photon) or 1.38 × 104 GM. According to the AFM data, three cycles of heat treatment of the solution leads to the formation of supramolecular assemblies of about 200 nm length. The optical spectrum exhibits long-wavelength absorption at λmax = 841 nm and the long-wavelength edge near 1300 nm. In the case of nanosecond 1064-nm laser irradiation, the linear absorption S 0 → S 1 is primary, having the cross section of σ0 = α0/N = 2.3 × 10−20 cm2. The known high quantum yield (close to unity) of triplet states of indium phthalocyanines suggests that the main nonlinear optical effect is determined by intersystem crossing S 1 → T 1 and triplet-triplet absorption T 1 → T 2. The absorption cross section is σ T-T = 1.14 × 10−19 cm2.

The electrodeposition of polyaniline (PANI) was carried out in potentiostatic, galvanostatic and potential sweep regimes in the presence of water-soluble polymeric sulfonic acids with different structure. The course of polymerization was traced by chronoamperometry, chronopotentiometry, cyclic voltammetry and in situ AFM measurements. The rigidity of the polyacid backbone, the distance between sulfonic groups on the backbone, the length and rigidity of the side chains containing sulfonic groups were shown to affect the onset potential of aniline oxidation, the character and the rate of the initial stages of PANI/polyacid film growth. AFM data indicated that the structure of the polyacids has a direct influence on the shape of PANI “nuclei” and the morphology of the film in the early stages of the electropolymerization. The obtained films were characterized by UV-Vis-NIR spectroscopy and cyclic voltammetry.

Interpolymer complexes of poly(3,4-ethylenedioxythiophene) (PEDOT) with a series of polyamidosulfonate dopants (PA) characterized by various degree of rigidity in the polymer chain were prepared by chemical and mechanochemical methods. It was shown that the morphology, conductivity, and spectral characteristics of the synthesized PEDOT/PA are determined by the method of preparation of the complexes and by the structure of the PA. It was established that the stability of aqueous dispersions of the interpolymer complexes PEDOT/PA is higher in the case of the chemical method of synthesis. At the same time the conductivity of the films is several orders of magnitude lower in comparison with the mechanochemically obtained analogs.

We demonstrate that the solvent-free mechanochemical method, previously used for the synthesis of polyaniline (PANI) protonated with low molecular weight inorganic acids, can be extended to the preparation of conductive, all-polymeric PANI/polyacid molecular composites. Two polymeric sulfonic acids differing in their chain rigidity were selected as PANI protonating agents, namely: poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA, flexible backbone polyacid) and poly(p,p′-(2,2′-disulfonic acid)-diphenylene- tere -phthalamide) ( t -PASA, rigid backbone polyacid). Spectroscopic (UV–vis–NIR, FTIR, EPR), morphological, structural (TEM), electrochemical and spectroelectrochemical properties of the mechanochemically prepared molecular composites were compared with those determined for their analogs synthesized by oxidative polymerization in aqueous solution. The mechanochemically synthesized molecular composites show a characteristic layer-type morphology, distinctly different from that observed for the composites prepared chemically in aqueous solutions. UV–vis–NIR and FTIR spectroscopy clearly indicate better polaron delocalization in the mechanochemically prepared samples. These results are in line with those obtained in ESR, electrochemical and spectroelectrochemical investigations unequivocally showing better charge carrier delocalization in the mechanochemically prepared composites. The measured dc-conductivity of the mechanochemically prepared samples is 24 mS/cm and 31 mS/cm for PANI/PAMPSA and PANI/ t -PASA, respectively.

The photoelectric and photorefractive characteristics of polyvinylcarbazole (PVK) composites with 0.15 wt % graphene at a wavelength of 532 nm have been measured. The dependence of the quantum efficiency of generation of mobile charge carriers as determined from the photocurrent is well approximated by the Onsager equation calculated accurate to E (0) (3) for the quantum yield of thermalized electron-hole pairs of phi(0) = 1 and their initial separation radius of r (0) = 10.9 . The long-wavelength edge of optical absorption for PVK lies at 365 nm. Thus, the photogeneration of mobile carriers during illumination of the composite at 532 nm is due to photoexcitation of graphene. The measurement of the photorefractive properties has revealed that the two-beam coupling gain coefficient is I" = 50 cm(-1) at E (0) = 150 V/mu m and equal intensities of incident beams. It has been found that at E (0) = 83.3 V/mu m, the two-beam coupling gain coefficient increases from 8 to 14 cm(-1) as the ratio of incident beam intensities I (1)(0)/I (2)(0) increases from 1 to 2.4.

Vanadium- and molybdenum-doped as well as undoped oxotungstate films electrodeposited on fluoride doped tin oxide (FTO) from peroxide-free solutions are considered as mediator electrocatalysts for inorganic anions reduction (by the example of IO 3 − ). The most risky aspect related to oxide degradation is addressed in electrochromic and voltammetric experiments. Potential-dependent optical absorption (300–1100 nm spectral range), coloration–decoloration kinetics, and capacity of the films are studied. Two-step coloration mechanism is ascertained, and the optimal wavelength (1100 nm) is chosen for further monitoring of the film redox state in the course of stability tests. The comparison of cycling stability in 0.5 and 2.0 M H 2 SO 4 in terms of capacity and coloration efficiency indicates the change of film degradation mechanism from dissolution to mechanical peeling with increase of acidity. The latter mechanism is shown to be less important for the film stability.

The energy structure and nature of intramolecular charge transfer have been determined for a series of synthesized 2,6-polyphenylquinolines (PPQs) containing resorcinol, oxygen, and phenylamine bridging groups between phenylquinoline cycles and possessing an arylene radical in the form of alkylated derivatives of carbazole or indolo[3,2-b]carbazole, as well as arylated derivatives of carbazole with nitro- and fluorine substituents. The analysis was based on data on their absorption spectra, photosensitivity, carrier photogeneration quantum efficiency, and luminescence. It is shown that the PPQ monomeric unit is a composite intramolecular charge-transfer complex (ICTC) between the donor arylene fragment and the acceptor quinoline cycle; the latter, in turn, is an ICTC between the donor bridging group and quinoline ring (when acceptor fluorine or nitro substituents are introduced into the carbazole structure, the complex becomes ternary), and the narrowest band gap (2.3 eV) corresponds to the PPQ having a phenylamine bridging group and a fragment of indolo[3,2-b]carbazole.

The template polymerization of aniline in the presence of polymeric sulfonic acids of various structures and their mixtures is studied. In the latter case, the dominant effect of a polyacid on the kinetics of aniline polymerization and the electronic structure of the resulting polyaniline complex is observed. As shown by viscometry measurements and IR studies, the intermolecular interaction between polyacids in their mixtures that leads to a change in the conformation of a flexible-chain polyacid is responsible for the dominant effect of a rigid-chain polyacid. The spectral and electrical properties of polyaniline-based interpolymer complexes are examined.

Polyvinylcarbazole (PVK) composites containing graphene in an amount of somewhat less than 0.15 wt % exhibit third-order dielectric susceptibility due to the presence of graphene, as well as photoelectric and photorefractive sensitivity at 1064 nm. The photorefractive (PR) effect is known to occur in a polymer composite that possesses both photoelectric sensitivity and nonlinear optical properties. The photoelectric, nonlinear optical, and PR properties of PVK composites with graphene have been considered in this paper.

Techniques of the production of polymer nanocomposites based on tetrapyrrole compounds with photoelectric, nonlinear optical, and photorefractive properties are considered. Supramolecular ensembles of Ru(II) and Ga(III) complexes with tetra-15-crown-5-phthalocyanine are found to form upon the deposition of thin films from tetrachloroethane solutions that have undergone several cycles of heating followed by slow cooling. The surface formation of supramolecular ensembles is studied with the use of atomic force microscopy. The assemblage is found to give rise to photoelectric and photorefractive sensitivity in the near-infrared range (measurements were carried out at 1064 and 1550 nm). The quantum yield of thermalized electron-hole pairs at 1064 nm in composites of polyvinyl carbazole and assembled Ga(III) complexes is 20 times as high as that in composites based on Ru(II) complexes. The largest two-beam coupling gain coefficient at 1064 nm (Γ = 120 cm−1 at E0 = 120 V/μm) was also observed for the Ga(III)-complex-containing composite. The third-order dielectric molecular susceptibility measured in tetrachloroethane solutions of the complexes weakly depends on the nature of the central atom and its axial neighborhood and falls in a range of γ = 4−5.2 × 10−32 esu.

The photoelectric and photorefractive characteristics of composites based on poly(vinylcarbazole) containing crown-substituted ruthenium phthalocyanine with axially coordinated pyrazine molecules, (R4Pc)Ru(pyz)2 (where R4Pc−2 is [4,5,4′,5′,4″,5″,4″′,5″′-tetrakis-(1,4,7,10,13-pentaoxatridecamethylene)phthalocyanine ion], pyz is pyrazine), have been studied. Supramolecular ensembles of these complexes are responsible for optical absorption and photoelectric and photorefractive sensitivity in the near IR region. It has been found that under the action of a 1064-nm laser, the quantum efficiency of formation of mobile charge carriers, estimated from the photocurrent, corresponds to the Onsager equation when the quantum yield of formation of thermalized electron-hole pairs φ0 = 0.35 and the separation distance is 9.8 A, irrespective of the (R4Pc)Ru(pyz)2 content. The kinetic curves of amplification of the information laser beam are bellshaped. This suggests that the photorefractive characteristics are underestimated owing to lowering to zero of the field E0 inside the layer as a result of buildup of space charge in the near-electrode space upon passing the dark current. The two-beam gain coefficient at an (R4Pc)Ru(pyz)2 content of 7 wt % is Γ = 62 cm−1 as estimated from the maximum of the bell-shaped curve.

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.

Photorefractive, nonlinear optical, and photoelectric characteristics at 1064 nm are discussed in the case of composites of polyvinyl carbazole (PVC) and closed single-walled carbon nanotubes with an additive of a visible-range cyanine dye with high electron affinity. Photorefractive properties are due to carbon nanotubes that are simultaneously spectral sensitizers toward laser irradiation at 1064 nm and responsible for the third-order dielectric susceptibility. Introduction of the dye leads to an increase in the photorefractive two-beam amplification factor of the laser bean and a significant increase in the quantum efficiency of free hole formation in PVC, but also a decrease in the third-order susceptibility. The dye plays the role of a super-sensitizer. It probably limits charge recombination in geminal pairs photogenerated in the range of bright interference fringes.

In this work, we carry out spectroelectrochemical studies of films of interpolymer complexes of polyaniline (PANI) prepared via the chemical and electrochemical template polymerization of aniline in the presence of polyamide sulfonic acids with different structures. It is shown that their spectroelectrochemical behavior in the near infrared region depends on the rigidity of the chain of the polymer sulfonic acid matrix. Electrodeposited films of PANI complexes with a rigid-chain polyacid exhibit a more intense absorption in the near infrared region (1000–2200 nm) and a less intense absorption in the absorption region of localized polarons (around 750 nm) in comparison with complexes with a flexible-chain polyacid. The comparison of the dependence of absorption in the near infrared region on potential with the cyclic voltammetry curves suggests that the chromophores responsible for this absorption are radical cations in nature. In the spectra of the films of chemically synthesized PANI complexes with a flexible-chain polyacid, during a long-term cycling in the region of potentials of the first redox stage of PANI, the absorption in the near infrared region which corresponds to delocalized polarons is also formed. This is apparently attributed to the intensification of the intermolecular interactions under the conformational fluctuations that accompany the change in the degree of oxidation of the film during cyclic voltammetry.

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.

Analysis of photoelectrical, nonlinear optical, and photorefractive properties of composites PVK containing singlewalled carbon nanotubes shows that addition of visible range cyanine dye with high electron affinity into the composites provides considerable increase of quantum efficiency of the mobile charge carries generation at 1064 nm, but reduces the third order susceptibility. As a result, photorefractive gain coefficient Γ of object laser beam increases twofold and achieves after pre-illumination the value 120 cm-1.

Poly(N-vinylcarbazole) layers containing tetra-5-crown-5-gallium phthalocyaninate (R4Pc)Ga(OH) are shown to possess photoelectric and photorefractive sensitivity at a wavelength of 1064 nm. This effect is associated with the formation of supramolecular ensembles of (R4Pc)Ga(OH) molecules with electronic optical absorption in the near-IR range and nonlinear optical properties. For the composite containing 5 wt % (R4Pc)Ga(OH) supramolecular ensembles, the dependence of the quantum efficiency of mobile-charge photogeneration on electric field E0 is well fit by the Onsager equation expanded to E03 at a quantum yield of electron-hole pairs of φ0 = 0.9 s with an initial separation radius of r0 = 9.8 A susceptibility χ(3) equal to 1.85 × 10−10 esu is measured via the well-known method of electric-field-induced second-harmonic generation. Two-beam-coupling gain coefficient Γ is found to be 80 cm−1 at E0 = 120 V/μm.

Photophysical and electrical properties of new synthesized 2,6-polyphenylquinolines (PPQs) containing an oxygen or phenylamine bridging group between quinoline cycles and, as an arylene radical, alkylated derivatives of carbazole or indolo[3,2-b]carbazole are studied. It is shown that the photosensitivity for new PPQs is 104–105 cm2/J and the photogeneration quantum yield of free carriers is as high as 0.15. Photophysical parameters increase with the phenylamine bridging group in place of the oxygen one and when using indolocarbazole instead of carbazole. It is found that a film of polyphenylquinoline containing an oxygen bridging group and an alkylcarbazole fragment in the polymer repeat unit exhibits “white” luminescence. Both electron and hole transport with a mobility of ∼10−6 cm2/(V s) are detected in films of all studied polymers. The conductivity value and type can be controlled by varying the chemical structure of the (oxygen or phenylamine) bridging group between PPQ cycles and by choosing carbazole or indolo[3,2-b]carbazole derivatives as an arylene radical.

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.