The paper describes results of comparative testing spray-coated layers of water-dispersible polyaniline (PANI) complexes with polyacids of different chemical structure as hole-injection layers (HILs) in an organic light-emitting diode (OLED) based on a poly(1,4-phenylenevinylene) copolymer (Super Yellow) as an emissive layer. OLEDs using HILs made of poly(3,4-ethylenedioxythiophene) complex with polystyrene sulfonate prepared by spin and spray coating were used as references. OLEDs using HILs based on PANI complexes with poly(4,4 '- (2,2 '-disulfonic acid)-diphenylene-tere-phthalamide) (t-PASA) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) demonstrated the highest current efficiencies of 6-7 cd/A, that is about 20% higher than this value in the best reference sample. The results were discussed in terms of crucial influence of the HIL morphology (analyzed in two scales) on the OLEDs' efficiency. Morphology of the HILs made of PANI:t-PASA and PANI:PAMPSA complexes were found to be most favorable in the following scales: few microns scale-moderately rough (but not completely smooth) intrinsic film texture derived from intermolecular packing; tens of microns scale-weak manifestation of irregularities induced by the spray coating method.

Electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of water-soluble fullerene derivatives was investigated. The electronic structure, morphology, spectroelectrochemical, electrochemical properties and near-IR photoconductivity of composite films of poly(3,4-ethylenedioxythiophene) with fullerenes were studied for the first time. It was shown that fullerene with hydroxyl groups creates favorable conditions for the formation of PEDOT chains and more effectively compensates for the positive charges on the PEDOT chains. The near-IR photoconductivity results from the generation of charge carriers due to electron transfer from the photoexcited PEDOT molecule to the fullerene acceptor.

Photosensitive hybrid layers are obtained by electrochemical polymerization of pyrrole and 3,4‑ethylenedioxythiophene in the presence of water-soluble sodium salt of zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate containing 16 ionogenic carboxylate groups. The process of the hybrid layer electrodeposition was found to occur most effectively in galvanostatic and potentiostatic modes on the sublayer of poly-3,4-ethylenedioxythiophene–polyacid complex. The electronic and chemical structure and morpho-logy of the hybrid layers of polypyrrole obtained in the presence of zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate were studied. Possible reasons are considered why the measured values of photosensitivity and external quantum yield of charge-carrier generation in polypyrrole–zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate are several times higher than in poly-3,4-ethylenedioxythiophene–zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate.

Chemical polymerization of aniline was carried out in aqueous solutions of sulfonated polysulfone (SPS) at different concentration ratios of aniline and SPS sulfo groups. The polymerization progress was investigated by in situ spectroscopy in the UV–visible–near-IR region. It has been shown that, with increasing concentration of SPS, the rate of polymerization increases. Films of water-dispersible complexes of polyaniline (PANI) with SPS were obtained by spray coating. The electronic and chemical structure, morphology and sensory (ammonia) properties of films of PANI–SPS complexes were studied for the first time.

Spray coating is a technologically -advanced and scalable method for applying various functional coatings. To optimize water -dispersible polyaniline (PANI) compositions for spray coating interpolymer complexes of PANI were synthesized by oxidative chemical polymerization in the presence of polysulfonic acids of different structure (different rigidity of polymer chain), different molecular weight and different content of the polyacid dopant. For flexible -chain polyacid the increase of molecular weight from 7200 to 281000 leads to 10 times decrease of the polymerization induction period from 2570 to 260 s which insufficiently depends on the monomer:polyacid ratio. For rigid -chain polyacid the decrease of monomer:polyacid ratio from 1:1 - 1:3 causes a decrease of the induction period from 285 to 90 min. In situ Raman spectroscopy in solution was used for the first time for direct monitoring the course of chemical synthesis of water -dispersible PANI complexes in solution. The obtained spray -coated layers were characterized by UV-Vis-NIR spectroscopy, cyclic voltammetry and spectroelectrochemistry. The sheet electrical resistance of the PANI-polyacid layers was found to be in the range of 7x10 4 - 5x10 6 Omega /sq, which was suitable for antistatic, electrostatic discharge, electromagnetic interference shielding and electrochromic applications.

The electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of a water-soluble Na+-containing fullerene with hydroxyl groups is studied. The monitoring of the electrosynthesis process by spectroscopic methods shows that during the polymerization of 3,4-ethylenedioxythiophene, fullerenol incorporates into the film composition, regardless of the fullerenol concentration used. The electronic structure, morphology, spectroelectrochemical and electrochemical properties, and near-IR photoconductivity of the poly-3,4-ethylenedioxythiophene–fullerenol composite films are studied for the first time. A mechanism of photoconductivity is proposed, related to the fact that during the photoexcitation of the composite, the electron transfer from the polaron (bipolaron) state of poly-3,4-ethylenedioxythiophene to the LUMO level of fullerenol increases the concentration of photogenerated charge carriers.

The electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) was performed in the presence of a water-soluble anionic copper and zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate containing 16 ionogenic carboxylate groups. The influences of the central metal atom in the phthalocyaninate and EDOT-to-carboxylate group ratio (1:2, 1:4, and 1:6) on the course of electropolymerization were studied using electrochemical methods. It has been shown that the polymerization of EDOT in the presence of phthalocyaninates proceeds at a higher rate compared to that in the presence of a low-molecular-weight electrolyte (sodium acetate). Studies of the electronic and chemical structure using UV–Vis–NIR and Raman spectroscopies showed that the use of copper phthalocyaninate leads to a higher content of the latter in PEDOT composite films. The 1:2 EDOT-to-carboxylate group ratio was found to be optimal for a higher content of phthalocyaninate in the composite film.

The influence of coating method (spray-coating or drop-casting onto horizontal substrate) on the electrochromic characteristics of the layers of water-soluble polyaniline-polyacid complex was investigated. It was shown that in case of addition of single-wall nanotubes the polyaniline-polyacid layers prepared by scalable spray-coating technology demonstrate high coloration speed an electrochromic efficiency.

In this review, we have summarized the main advantages of the method of spectroelectrochemistry as applied to recent studies on electrosynthesis and redox processes of electroactive polymer composite materials, which have found wide application in designing organic optoelectronic devices, batteries and sensors. These polymer composites include electroactive polymer complexes with large unmovable dopant anions such as polymer electrolytes, organic dyes, cyclodextrins, poly(β-hydroxyethers), as well as polymer-inorganic nanocomposites. The spectroelectrochemical methods reviewed include in situ electron absorption, Raman, infrared and electron spin resonance spectroscopies.

Electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of water-soluble sodium salt of zinc octa(3′,5′-dicarboxyphenoxy)phthalocyaninate containing 16 ionogenic carboxylate groups is studied. By using electrochemical and spectral methods of monitoring the course of the electrosynthesis the EDOT polymerization in the presence of phthalocyaninate is shown to proceed at higher rate compared to that in the presence of low-molecular electrolyte (sodium acetate). The electropolymerization acceleration is discussed in terms of templating effect of locally-ordered carboxylate groups of phthalocyaninate in analogy with the EDOT template electropolymerization in the presence of polyelectrolytes. Electronic and chemical structures, morphology, spectroelectrochemical and sensor properties (with respect to ammonia) of the PEDOT composite films obtained in the presence of water-soluble phthalocyaninate are studied for the first time.

The influence of the coating method (spray-coating or drop-casting onto horizontal substrate) on the electrochromic characteristics of the layers of water-soluble polyaniline-polyacid complex was investigated. It was shown that, in the case of adding single-wall nanotubes, the polyaniline-polyacid layers prepared by the scalable spray-coating technology demonstrate high coloration speed and electrochromic efficiency. Keywords: polyaniline, electrochromism, polyacid, carbon nanotubes.

Thin layers of poly(3,4-ethylenedioxythiophene) complexes with various sulfonated polyelectrolytes were formed electrochemically in a galvanostatic regime. These transparent hole transport layers were used in CH3NH3PbI3 perovskite solar cells and the influence of the polyelectrolyte structure on the device performance was featured.

Films of polypyrrole(PPy)-polyelectrolyte(PE) complexes have high potential as active material in bio-sensing and biomedical applications due to high hydrophilicity and biocompatibility, as well as, as an electroactive polymer matrix in electrode materials for rechargeable lithium batteries and supercapac-itors. Comparative study is presented on the influence of PE structure on the properties of PPy-PE complexes. PPy films were prepared by pyrrole electrochemical polymerization in cyclic voltammetry, potentio-and galvanostatic regimes in aqueous solutions of acid or salt forms of sulfonated polyelec-trolytes (PEs) with different flexibility of the polymer backbone. Electrochemical polymerization of pyr-role in these conditions results in obtaining high-quality polymer films efficiently rechargeable in aqueous and nonaqueous media. The films obtained were characterized by cyclic voltammetry, UV-Vis-NIR spec-troelectrochemistry in aqueous and nonaqueous media, as well as, by Raman spectroelectrochemistry in aqueous medium. Gaussian deconvolution of the Raman spectra in the range of 850-1150 cm & minus;1 allowed one to trace peculiarities of polaron-bipolaron transitions depending on the PE structure. It was shown that the films of PPy complexes with the salt forms of rigid-chain PEs had redox numbers comparable to those of the complexes with the flexible-chain PEs, but they were more stable during CV cycling in nonaqueous medium. (c) 2021 Elsevier Ltd. All rights reserved.

The photoelectric and optical characteristics of an organic solar cell (OSС) with a hole-transport layer based on a polyaniline complex and a photoactive layer with a bulk heterojunction based on P3HT polythiophene derivative and PC71BM fullerene have been studied. The results of modeling the optical properties of the functional layers and experimental measurements of the OSC characteristics enabled the optimal values of the thickness of the functional layers resulting in the maximum power conversion efficiency of the device to be identified. It has been determined that the hole-transport layer with a thickness of 30–60 nm, while having a transmission of more than 80%, effectively transferred holes to the photoanode from the photoactive layer, in which the exciton generation rate was 5.6–5.9 × 1016 cm–2 s–1. These values of the exciton generation rate at the maximum total light absorption in the device were provided by a photoactive layer with a thickness of 90–100 nm.

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.

ҚАЗАҚСТАН РЕСПУБЛИКАСЫ ҰЛТТЫҚ ҒЫЛЫМ АКАДЕМИЯСЫНЫҢ БАЯНДАМАЛАРЫ

Thin films of conducting polymer complexes with polysulfonic acids of various structures were electrochemically deposited onto transparent FTO electrodes. The behavior of the polymer-based optical ammonia vapor sensors in response to various concentrations of ammonia vapors, ranging from 5 to 135 ppm, was investigated, including the response time and response amplitude. It was found that the nature of the conducting polymers (poly (3,4-ethylenedioxythiophene), polypyr-role, polyaniline), as well as the structure of the polyacids, affected the sensing performance of the obtained complexes.

The electrochemical synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) was first carried out in the presence of mixtures of flexible-chain and rigid-chain polyacids and their Na-salts. Earlier on with the example of polyaniline, we have shown the non-additive effect of the rigid-chain component of polyacid mixtures on the electrodeposition of polyaniline films, their morphology and spectroelectrochemical properties. In this study, we confirmed the non-additive effect and showed that such mixed PEDOT–polyelectrolyte films possess unique morphology, spectroelectrochemical and ammonia sensing properties. The electrosynthesis was carried out in potential cycling, galvanostatic and potentiostatic regimes and monitored by in situ UV–Vis spectroscopy. UV–Vis spectroelectrochemistry of the obtained PEDOT–polyelectrolyte films revealed the dominating influence of the rigid-chain polyacid on the electronic structure of the mixed complexes. The mixed PEDOT–polyacid films demonstrated the best ammonia sensing performance (in the range of 5 to 25 ppm) as compared to the films of individual PEDOT–polyelectrolyte films.

Electrochemically synthesized poly(3,4,-ethylenedioxythiophene) (PEDOT) films obtained in the presence of eight different polysulfonate dopants are comparatively studied by means of electrochemical quartz crystal microbalance (EQCM) and X-ray Photoelectron Spectroscopy (XPS). Differences with respect to oxidation and doping levels (OL and DL), polymerization efficiency and redox behavior are revealed based on the interplay of three factors: the type of the dopant (acid or salt form), flexibility of the polysulfonate chains and molecular weight of the polysulfonate species. For the rigid- and semi-rigid-chain dopants, use of the salt form results in higher OL and DL values and substantial involvement of solvent molecules in the course of polymerization and redox transitions whereas in the presence of their acid form compact PEDOT films with minor ionic-solvent fluxes upon redox transitions are formed. In contrast, use of the salt form of the flexible chain polysulfonates results in PEDOT with lower OL and DL in comparison to the corresponding acid form. Significant effects are observed when comparing flexible chain dopants with different molecular weights. From a practical point of view the present investigations demonstrate the large scope of possibilities to influence some basic properties of PEDOT (Ol and DL, intensity and type of the ionic and solvent fluxes upon redox transition) depending on the used polysulfonate dopants.