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The possibility of target control of the electro-optical properties of polymethacrylate with covalently bound azobenzene chromophores in a side chain by introducing metal ions capable of chromophore coordination, acceptor substituents that change the dipole moment of an azobenzene fragment, and organic dyes that expand the range of light absorption of azobenzene chromophore were considered. The mechanism of action of these factors was analyzed. [ABSTRACT FROM AUTHOR]

The influence of an electric field on the transmission of linearly polarized light by polyvinylbutyral composite films doped with particles of the heterometallic complex (NH4)2{[Cu(dien)(H2O)]2[α-V2Mo6O26]}∙5H2O (dien = diethylenetriamine) was studied. The absorption became anisotropic if an electrostatic field was applied during irradiation of the composites by linearly polarized light. The observed electrooptical effect was explained by photo-induced optical anisotropy that was caused by the linearly polarized light and changed in space due to reorientation of the dipole moment of photogenerated electron–hole pairs in the composite under the action of the external electric field. [ABSTRACT FROM AUTHOR]

Recording media for polarization holography based on new azobenzene-containing monomers with octylmethacrylate are created. Their electrophysical and information properties are investigated. Improvement of the diffraction efficiency of holograms in these media in an external electric field formed by charging the free surface of the polymer film in a corona discharge is demonstrated. The diffraction efficiency is improved more in the copolymer, in which the azobenzene fragments possess larger dipole moments. [ABSTRACT FROM AUTHOR]

Photosensitive polymeric film composites based on nonphotoconducting poly(vinyl butyral) doped with heterometallic Cu/M complexes (M = Ca, Sr) were synthesized and investigated. These composites possessed photoconducting and photovoltaic properties and electron-type photoconductivity. The greater photocurrent for composites with complexes having shorter distances between the nearest Cu metal centers was attributed to the greater probability of electron transfer between these centers. [ABSTRACT FROM AUTHOR]

Peculiarities of photoconductivity of film composites based on branched carbazolyl-containing oligomers with a branching center on a silicon atom have been studied. An increase in the photocurrent and a decrease in the photoresponse time have been found in the film composites on passing to the oligomers with larger numbers of branches (from 2 to 3 and 4). It is assumed that the increase in the photoconductivity is determined by the increase in the effective mobility of the holes. A phenomenological model describing the effects observed is proposed. [ABSTRACT FROM AUTHOR]

Recording media for polarization holography have been created using copolymers of azobenzene monomers and octyl methacrylate, and the electrophysical and information properties of these materials have been studied. The increase in the diffraction efficiency of holograms in an external electric field has been found to be faster in copolymers with an azo chromophore possessing a larger dipole moment. [ABSTRACT FROM AUTHOR]

Holograms with a plane wavefront for parallel and orthogonal orientation of polarization of the light beams were obtained in films of the 4-[(2-nitrophenyl)diazenyl]phenyl methacrylate copolymer with octyl methacrylate, and the effect of an external electric field on their diffraction efficiency was investigated. Two effects from the electric field on the diffraction efficiency of the reconstructed holograms were observed: a fast effect leading to decrease of the diffraction efficiency and a slow effect leading to increase of the diffraction efficiency in the reconstructed holograms. The mechanism of formation of the latent holographic image and the effect of the external electric field on it are due not to the photosemiconducting properties of the films but to optical anisotropy in the isomers of the azobenzene groups and the formation of regular surface relief in the films. [ABSTRACT FROM AUTHOR]

We have synthesized and studied novel photosensitive polymer film composites based on non-photoconducting polyvinyl butyral doped with heterometallic Cu/Mo complexes. We have established that these composites have photoconducting and photovoltaic properties and are characterized by hole-type photoconductivity. The photocurrent and the photo-EMF are higher for composites in which complexes are used that have a shorter distance between nearest-neighbor metallic copper centers, which is explained by better conditions for transport of nonequilibrium holes. [ABSTRACT FROM AUTHOR]

The photoconductivity of film composites based on branched carbazolyl-containing oligomers with the branching center at a silicon atom was investigated. It was found that the photocurrent increases and the photoresponse time in the film composites decreases in the transition to oligomers with greater branching. It is suggested that the increase in photoconductivity is determined by increase in the effective mobility of the holes. [ABSTRACT FROM AUTHOR]

The properties of composites for the photothermoplastic recording of holograms based on cooligomers with common naphthyl and different (fluorenylidene, anthracenyl) fragments were investigated. It was found that increase in the amount of halogen substituent Clin the cooligomer reduces the diffraction efficiency of the holograms. The possible practical application of such recording media was demonstrated. [ABSTRACT FROM AUTHOR]

It was found that the photophysical characteristics of film composites based on poly(vinyl butyral) with additions of particles of the hetero-polyoxometalate complex (NH){[Cu(en)][PMoVO]}·9HO have an unusual dependence on the duration of illumination with visible light, which is expressed as change in the sign of the photocurrent during long-term illumination. It is suggested that the negative photoconductivity is due to the formation of significant volume charge in the volume of the composite film. It was concluded from analysis of the photovoltaic characteristics that the volume charge is formed by non-equilibrium negative electric charges. A phenomenological model that describes the observed effect is proposed. [ABSTRACT FROM AUTHOR]

Photosensitive polymer fi lm composites based on non-photoconductive polyvinyl butyral with an added heterometallic Cu/Ca complex were prepared and investigated. It was found that such composites had photovoltaic properties and exhibited a photodielectric effect when irradiated in the complex absorption band. The mechanism and characteristics of the photovoltaic and photodielectric effects in the studied fi lm composites were discussed. [ABSTRACT FROM AUTHOR]

Composite films based on a carbazolyl-containing oligomer with polymethine dye additives exhibit a change in the magnitude and sign of the photovoltaic response on the passage from the samples with free surfaces to sandwich structures. It is concluded that the photovoltaic effect in the former case is determined by the diffusion of positive charge carriers possessing higher mobility, while in the latter case this effect is controlled by a significant drift of carriers in the electric field created by different work functions of the charge-collecting electrodes. It is shown that the photovoltaic effect also takes place in a nonphotoconducting polymer (polyvinyl ethylal). However, neither the sign nor magnitude of the effect in this case change on the passage from the samples with free surfaces to sandwich structures. [ABSTRACT FROM AUTHOR]

It was found that film composites based on carbazolyl-containing cooligomer with additions of cationic polymethine dyes exhibit photovoltaic characteristics in the absorption region of the dyes. If the length of the polymethine chain is reduced the value of the photovoltaic response is increased as a result of decrease in the energy of the highest occupied orbital of the dye molecule. In samples of the composite films with free surface area the photovoltaic effect is determined by diffusion of the more mobile positive carriers (the Dember effect) and by their recombination time. [ABSTRACT FROM AUTHOR]

We have obtained photoconducting film composites based on cobalt(II) oleate and octanoate salts, sensitized by anionic or cationic polymethine dyes. We have studied their electrical conducting and photoconducting properties. High photosensitivity is observed for octanoate-based films, in which the cobalt ion concentration is higher than in oleate-based films. We suggest a scheme for the process of photogeneration of nonequilibrium charge carriers in such composites. [ABSTRACT FROM AUTHOR]

Heterostructures comprising a merocyanine dye (M1) film deposited onto a poly-N-epoxypropylcarbazole (PEPC) film have been created, and their photoconducting, photodielectric, and photovoltaic properties have been studied. The PEPC/M1 heterostructures exhibit the photodiode and photoelectric converter properties. It is concluded that the p- n junction in these heterostructures is ensured by the hole character of conductivity in the polymer and the bipolar conductivity of the deposited dye film. [ABSTRACT FROM AUTHOR]

New bis-azo dyes and complexes of these with cobalt are synthesized and used in photo-active film polymer composites based on an octyl methacrylate:acrylonitrate (1:1) copolymer. After creation of an optical anisotropy in these films, the kinematics and spectral characteristics of the electro-optical effect are studied. A huge change (greater than 80 %) is detected in the intensity of the light passing through a polarizer, the film, and an analyzer. The giant electro-optical effect and its rather fast kinetics are explained by the elasticity of the polymer matrix, which contains polar groups, and by the compatibility of the new azo-compounds with the matrix. [ABSTRACT FROM AUTHOR]

The subject of investigation is poly- N-epoxypropylcarbazole and poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene-vinylene] films with zinc 2,3,9,10,16,17,23,24-octabutylphthalocyanine additives. The photoconducive and photodielectric properties of these heterostructures are studied in the absorption range of the metal complex. The photosensitivity of the structures depends on the triplet state of photogenerated electron-hole pairs, their dissociation in an external electric field, and charge carrier trapping. The increased photosensitivity of the heterostructures compared with that of constituent films is explained by a higher efficiency of dissociation of the photogenerated electron-hole pairs and a reduced influence of non-equilibrium carrier traps at the interfaces. [ABSTRACT FROM AUTHOR]

Spectral, photosemiconducting, and information properties of holographic recording media with films of glycidyl carbazole-butyl glycidyl ether cooligomer, methylated ferrocenyl oligoglycidyl carbazole, and o-carboxybenzoyl ferrocene glycidyl ether cooligomer with squaryl dye additives were studied. An increase in the holographic sensitivity and photoconductivity of recording media with ferrocenyl-containing cooligomer films in comparison with media based on a glycidyl carbazole cooligomer was found. This phenomenon was attributed to the effect of iron ions on the singlet-triplet conversion rate in photogenerated charge pairs, which was validated by analyzing the dependence of the photocurrent on the external magnetic field. A phenomenological model of the effect of ferrocene on the photoconductivity of studied films was proposed. [ABSTRACT FROM AUTHOR]

The effect of an external electrostatic field on the photoluminescence spectra and photoconductivity of symmetric and asymmetric cationic polymethine dyes with end groups possessing different electron-donating properties (basicity) in polymer films based on photoconductive poly-N-epoxypropylcarbazole and nonphotoconductive polyvinylethylal is studied. It is found that application of an electric field to films can both decrease and increase their luminescence intensity. The strongest decrease in the luminescence intensity is observed for symmetric dyes in poly-N-epoxypropylcarbazole films with either a decrease in the electron-donating ability of the end groups or with a decrease in the length of the polymethine chain. Colored polyvinylethylal films exhibit both a negative and a positive effect of the field on the photoluminescence intensity. The character of changes in the luminescence spectra does not depend on the electron-donating ability of the end groups. The spectral effects are explained by a change in the probability of vibronic transitions due to the redistribution of the electron density in the chromophore of the dye in the ground and excited states in an external electric field. [ABSTRACT FROM AUTHOR]

We have studied the optical, photoelectric and dielectric properties of polymer composite films based on polyvinyl butyral with additives of a mixed-metal Mn(III)/Cu(II) complex. We observed high photoconductivity of the films obtained in the region of absorption by the complex. The slow photocurrent rise and relaxation kinetics are connected with the low mobility of the photogenerated charge carriers. [ABSTRACT FROM AUTHOR]