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A study was carried out on the photovoltaic and photoconductive properties of fi lm composites of a styrene copolymer with nonyl methacrylate and polyNepoxypropylcarbazole doped with lanthanide complexes Ln2L6·PS (Ln = Nd, Eu, Gd, Yb), HL is the carbacylamidophosphate ligand, CCl3C(O)N(H)P(O)(NEt2)2, N-[bis(diethylamino) phosphoryl]2,2,2-trichloroacetamide; PS is 3,6-dipyridin-2-yl-1,2,4,5-tetrazine, C5H4N–C2N4–C5H4N). In the visible spectral range, these composites were found to have holetype photoconductivity. The internal photoelectric effect is a function of the photogeneration of charge carriers from the metal complex molecules and the sensitizer. EPR was used to study the kinetics of the formation and relaxation of the photogenerated charge carriers. We conclude that the metal complex molecules in the polymer composite enhance the efficiency of photogeneration of nonequilibrium charge carriers and thereby affect the photovoltaic properties of the composites.

The recording media for polarization holography based on azobenzene polymers are obtained by polymer-analogous transformations of polymethacrylic acid and its copolymers with alkyl methacrylates. Their informational properties were investigated when recording holograms of a plane wavefront. It has been found that the recording and relaxation times of holograms are approximately the same. They are defined mainly by the processes of trans-cis-isomerization of azobenzene groups without formation of surface relief of the polymeric film. The efficiency of the trans-cis-isomerization process decreases, if a heavy substituent is present in the azobenzene chromophore. These results are of practical interest in the choice of photosensitive materials for holographic recording media with optimal information characteristics.

Photovoltaic and photoconductive properties of styrene–nonyl-methacrylate copolymer and poly(N-epoxypropylcarbazole) film composites doped with the tetranuclear metal complex Cu4L4(OCH3)4 (L– = N,N′-dibenzyl-N″-trichloroacetyltriamidophosphate) and a sensitizer, i.e., an organic compound with intramolecular charge transfer, were investigated. It was found that these composites had hole-type photoconductivity in the visible spectral range. The internal photoelectric effect was determined by the photogeneration of charge carriers from the metal complex and sensitizer. The kinetics of formation and relaxation of photogenerated charge carriers were studied using ESR. It was concluded that metal-complex molecules in the polymer composite increased the efficiency of photogeneration of nonequilibrium charge carriers and affected the composite photovoltaic properties.

On the base of a new polyurethane with azobenzene dopants, recording media for polarization holography have been created, and their information properties have been studied when recording holograms of a plane wavefront. It has been found that the recording and relaxation times of holograms are short, and it is defined by the processes of trans-cis-isomerization of azobenzene groups without formation of the surface relief in the polymer film. The obtained results are of practical interest in the choice of photosensitive materials for holographic recording media for dynamic holography.

Based on polymers with the addition of azo dyes as chromophores and azopolymers with the same covalently linked chromophores, recording media for polarization holography are created and their properties are studied when recording holograms of a plane wave front with parallel and perpendicular polarization of recording rays. It is found that the diffraction efficiency and the storage time of holograms are much longer in recording media with films of azo polymers in comparison with polymeric solid solutions of azo dyes. In the latter case, the energy of light is spent only for the trans–cis isomerization of azo dye molecules during exposure of holograms and the polymer chains do not undergo deformation with the formation of a surface relief in the polymer film. Therefore, it is preferable to use recording media based on solid solutions of azo dyes in dynamic polarization holography.

The effect of halogens in carbazolyl-containing oligomers on the information properties of recording media in the photothermoplastic method of recording holograms is studied. An increase of photosensitivity was observed for such media with halogens present in their composition. It was shown by photoactivated electron paramagnetic resonance that the lifetime of the photogenerated charge pairs is increased in the presence of halogens. This is due to the increased probability of photogeneration of charge pairs in the triplet state for the modified oligomers compared with their analogs. It is presumed that modification of the photoconductive polymers with halogens is one way of increasing their photosensitivity and for other practical applications (photovoltaics, molecular electronics).

Photoconductive and photovoltaic properties of composite films based on poly-N-epoxypropylcarbazole with added new merocyanine dyes derived from fluorene were investigated. The composites were found to have hole-type photoconductivity although the internal photoeffect was determined by photogeneration of charge carriers from dye molecules and transport of holes along polymer-matrix donor fragments according to jump-type conductivity. It was concluded that the photovoltaic response increased if merocyanine dyes with electronic structures close to that of the ideal polymethine were used.

A study was carried out on the photovoltaic and photoconductive properties of film composites of a copolymer of styrene with nonyl methacrylate and poly-N-epoxypropylcarbazole doped with the tetranuclear metal complex Cu4L4(OCH3)4 (L− = N,N′-dibenzyl-N″-trichloroacetylphosphotriamide) using an organic intramolecular charge transfer compound as a sensitizer. In the visible spectrum, these composites have hole-type photoconductivity, while their internal photoelectric effect is related to the photogeneration of charge carriers from the metal complex molecules and the sensitizer. The metal complex molecules in the polymer composite were found to increase the efficiency of photogeneration of nonequilibrium charge carriers and thereby affect the photovoltaic properties of the composites.

The photoconductive and photovoltaic properties of fi lm composites based on poly-N-epoxypropylcarbazole doped with a metal complex (a derivative of nickel dithiolene) were studied. It was found that these composites possess hole-type photoconductivity and that the internal photoeffect is determined by photogeneration of charge carriers from the metal complex and by transport of holes through the donor fragments of the polymer matrix.

The photoconductive and photovoltaic properties of film composites derived from poly-Nepoxypropylcarbazole and additives of some indole derivative dyes, namely, squaraine, thiosquaraine, and croconaine, were studied. Such composites were found to have hole-type photoconductivity. The internal photoelectric effect is a function of the photogeneration of charge carriers from the dye molecules and transport of the holes along the donor fragments of the polymer matrix. The photovoltaic effect decreases in going from squarate to thiosquarate and croconate. This behavior is attributed to greater internal conversion due to the shift of the absorption region of the dyes in the near-IR spectral range.

Recording media for polarization holography have been created on the basis of 4-((2-bromo-4-nitrophenyl)diazenyl)phenyl methacrylate copolymers, and the properties during that they manifest during recording of holograms of a plane wavefront have been studied. It has been found that the hologram recording rate at room temperature is the same for the perpendicular and parallel polarization of recording rays and the hologram relaxation rate is higher in the case of perpendicular polarization orientation of recording rays. It has been shown that the diffraction efficiency of holograms does not exhibit a monotonic relation with the film softening temperature.

The photoconductive and photovoltaic properties of fi lm composites based on the new oligomer polyepoxypropylpyridobenzothiazole were compared with the known poly-N-epoxypropylcarbazole, which contains the squarylium dye as a photoconductivity sensitizer. It was found that these composites have hole-type photoconductivity, and the internal photoelectric effect is determined by the photogeneration of charge carriers from dye molecules and by transport of the holes along the donor fragments of the polymer matrix. The photoconductivity and photovoltaic response increase in the transition to the new oligomer with the more effi cient conjugation system in the donor fragments.

Films of a nonphotoconducting copolymer of styrene with octyl methacrylate doped with azobenzene dyes have been used to create recording media for polarization holography. An increase in the concentration of the azo dye with electron-donor groups in the chromophore, in contrast to unsubstituted azobenzene, leads to photoconductivity and increased diffraction efficiency of the polarization holograms. The diffraction efficiency can also be increased by charging the films in a coronal discharge. Holographic media with such films can find use both for dynamic polarization holography and for the prolonged storage of holographic recordings similar to photothermoplastic recording media.

It was found that film composites of the copolymer of styrene with octyl methacrylate with additions of the monomers of pyrido[2,1-b]benzothiazole derivatives have hole-type photoconductivity while the internal photoelectric effect in this medium is determined by the photogeneration of charge carriers from the monomers and transfer of nonequilibrium charge carriers through these monomers. In transition to a monomer with a more efficient conjugation system the photoconductivity and photovoltaic response are increased.

In the films of copolymer 4-((2- nitrophenyl)diazenyl)phenylmethacrylate with octylmethacrylate the holograms of the plane wave front were registered for parallel and orthogonal orientations of polarization vectors of the object and reference light beams. The diffraction efficiency of the holograms is higher when pulsed exposure during holographic recording is used instead continuous exposure. After the holograms registration, the diffraction efficiency of the reconstructed holographic image can be significantly increased by charging the film surface in the corona discharge. This effect is explained by strengthening the modulation of the surface relief of the films.

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.

Peculiarities of the polarization holographic recording in the samples with the films of copolymer poly[4-((2-nitrophenyl)diazenyl)phenylmethacrylate-co-octylmethacrylate] with free surface and in the sandwich-structures with solid covering layer are investigated. Time of the holographic recording and its storage is less in the sandwich-structures. It was concluded, that in the sandwich-structures, geometric relief of the film surface does not appear during the recording.

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.

The photovoltaic and photoconductive properties of film composites of a copolymer of styrene with octyl methacrylate and additions of the monomer (Z)-2-(4-methylthiazol-2-yl)-2-(pyrrolidin-2-ylidene)acetonitrile (HL) and complexes of NiL2, CoL2, and CuL2 were investigated. It was established that these composites have hole-type photoconductivity while the inner photoeffect is determined by photogeneration of charge carriers from the HL monomers and by transport of nonequilibrium charge carriers among these monomers. The photovoltaic response increases with the metal complexes in the following order: CuL2, NiL2, CoL2.

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.

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.

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.

It has been found that films of polymer composites based on polyvinyl alcohol doped with a xanthene dye possess photovoltaic properties, and the photovoltaic response varies little at the dye concentration greater than 10 wt % with respect to the weight of the polymer. The photovoltaic effect is due to photogeneration of charge carriers in the dye aggregates and transport of nonequilibrium charge carriers among them. It is concluded that, in order to reduce the production cost of photoactive media for photovoltaic cells, it is possible to use cheap polymers with a low concentration of organic dyes.

A study was carried out on the photophysical properties of photothermoplastic holographic recording media based on film composites derived from linear and branched cooligomers. The diffraction efficiency of the recorded holograms was enhanced by using branched oligomers in the holographic recording media.

We have established that as the content of glycidyl carbazolyl fragments increases in their copolymers with α-naphthyl glycidyl ether, the photoconductivity of the films increases but the diffraction efficiency of the holograms decreases. Media based on bromine-containing co-oligomers are more holographically sensitive due to the high surface discharge rate for the films during exposure and formation of a latent electrostatic image.

The new heterostructures comprising a squarylium dye (SQ) film deposited onto a oligo-N-epoxypropylcarbazole (OGC) film have been created, and their photoconducting, photodielectric, and photovoltaic properties have been studied. The OGC/SQ heterostructures exhibit the photodiode properties. It is concluded that the p–n junction in these heterostructures is ensured by the hole character of conductivity in the oligomer and the bipolar conductivity of the deposited dye film.

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.

The information properties of holographic recording media for photothermoplastic recording with films of oligomer composites based on carbazolyl-containing linear and star co-oligomers with branching centers on silicon and germanium atoms have been studied. The media based on the star oligomers possess higher holographic sensitivity due to greater plasticity and ability to accumulate space electrical charge during exposure. The buildup of space electrical charge results from the capture of photogenerated holes by energy traps created by dimers formed from terminal carbazolyl groups, whose amount is larger in macromolecules of radial oligomers than in linear oligomers.

The effect of negative photoconductivity of ferrocenyl-containing oligomer films doped with a merocyanine dye based on ferrocene and tetranitrofluorene has been found. The decrease in the conductivity current and its recovery after switching off light are in agreement with the decrease and the recovery of the dielectric loss tangent in the films studied. The phenomenological model is suggested in which the buildup of space charge from nonequilibrium current carriers and its effect on electric conductivity of the films are taken into account. It is supposed that energetic traps for nonequilibrium charge carriers are formed due to proximity of the ferrocenyl fragments in the oligomer and a long distance between its end groups.

Photophysical and information properties of the holographic recording media (HRM) based on films of ferrocenyl-containing siloxane oligomer, glycidylcarbazole-butylglycidylic ether cooligomer, ferrocenemethylated oligoglycidylcarbazole, and cooligomer of o-carboxybenzoilferrocene glycidylic ether doped with squarilic dye and(or) with merocyanine dye based on ferrocene and tetranitrofluorene are investigated. It is found that the holographic sensitivity is absent for the media based on ferrocenyl-containing siloxane oligomer, and that the holographic sensitivity is present for the films based on glycidylcarbazole. It has been found that the holographic sensitivity and the photoconductivity of the media based on glycidylcarbazole cooligomers increases with the ferrocene content. This effect has been explained by the influence of iron ions on the rate of singlet–triplet conversion in photogenerated pairs of charges.

We have studied the photoconducting properties of films of ferrocene-containing oligomer with additives of squarylium and merocyanine dyes based on ferrocene and tetranitrofluorene in the dye absorption region. We have studied the characteristic features of the effect of an external magnetic field on the photocurrents. After the magnetic field is turned on, the photocurrent increases in the samples with squarylium dye and decreases in the samples with merocyanine dye. We discuss the hypothesis that in the first case, as a result of an internal photoelectric effect, predominantly triplet charge pairs are formed, while in the second case predominantly singlet charge pairs are formed. The latter may be one of the reasons for the higher photoconductivity of films with squarylium dye compared with merocyanine dye.

We have studied the photoconducting and photodielectric properties of heterostructures based on poly-N-epoxypropylcarbazole and poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] doped with zinc 2,3,9,10,16,17,23,24-octabutylphthalocyanine located between SnO2 :In2O3 and Ag electrical contacts, in the absorption region of the metal complex. We have observed that the photosensitivity is higher when the poly-N-epoxypropylcarbazole films are deposited on a SnO2 :In2O3 electrode. The increased photosensitivity of the heterostructures compared with monolayers of the films is explained by the high efficiency of dissociation of the photogenerated electron–hole pairs and the decrease in the effect of traps for nonequilibrium charge carriers at the film interfaces.

The photothermoplastic medium based on the films of photosensitive polymeric composites with semiconductor properties is developed for application in optical information recording and storage, in holographic interferometry, as well as for medical purposes. This medium was used in the modified holographic device for determination of changes of the refractive index of homogeneous and inhomogeneous liquid objects. The technique and holographic equipment were modified by employing the specially developed and produced transparent cuvette of special shape and the phase shifting interferometry method. Experimentally demonstrated precision of the measurements is not less than 10-5.

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.

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.

Holographic properties, dark conductivity, and photoconductivity of films based on carbazolyl-containing cooligomer doped with zinc 2,3,9,10,16,17,23,24-octabutylphthalocyanine (PcBuZn), double-decker dysprosium phthalocyanine (Dy(Pc)2), and Pr2O3 particles were studied. The films with PcBuZn are characterized by higher photoconductivity, which is due to photogeneration of long-lived triplet charge pairs. The presence of Dy in the sensitizer molecules or Pr2O3 in the films enhances their photoconductivity, a change that is attributed to an increase in the rate of the singlet-triplet intersystem crossing of the charge pairs.

Comparative analysis of the holographic recording mediums based on films of poly-N-epoxypropylcarbazole doped with ionic, merocyanin and intra-ionic organic dyes is carried out. Electric- and photo-conductivity of these film are investigated. A possibility of using merocyanin and intra-ionic dyes as effective sensitizers of the recording mediums for one- and multi-exposition holographic recording is shown.

We have created holographic recording media based on films of carbazolyl-, fluorenyl-, naphthyl-, and anthracenyl-containing oligomers and co-oligomers in which an intraionic organic dye is used as the sensitizer. We have established that the photoconductivity of the films and the photosensitivity of the recording media are higher in the case of co-oligomers with different donor moieties. We conclude that in the films of co-oligomers with different donor moieties in the “end” groups of the polymer chain, there is reduced probability of formation of excimers, which are centers for capturing photogenerated charge carriers, and therefore the photoconductivity of the film increases.

The effect of doping with CdS nanoparticles of recording medium films for the thermoplastic holographic recording process, which are based on photosemiconductors (oligomers and cooligomers of glycidylcarbazole) and a dielectric (a styrene copolymer with octyl methacrylate) containing a photoconductivity sensitizer, on their photosensitivity was studied. The enhancement of photosensitivity of films by doping with nanoparticles is associated with the appearance of an additional channel for transport of electrons generated from sensitizer molecules. A difference in informational properties between the oligomer and the polymer films was revealed.

We investigated the influence of additions of Fe2O3, ZnO, and CdS nanoparticles in films of holographic recording media based on photosemiconductors (oligomers and co-oligomers of glycidyl carbazole) and a dielectric (copolymer of styrol with octylmethacrylate) that contain an organic compound with intramolecular charge transfer as a sensitizer of photoconductivity in the visible and near-IR regimes on their photoconducting and thermoplastic properties. The photoconduction current for light wavelengths larger than the red boundary of absorption of the nanoparticles is determined by the photogeneration of charge carriers from the sensitizer molecules and by their transport inside and between nanoparticles. The increase in the photosensitivity of films on addition of nanoparticles is attributed to the appearance of an additional channel for the transport of the electrons generated from the photogeneration centers. A new difference between the rheological properties of the films based on organic photosemiconductors and dielectrics has been revealed.

Information characteristics of holographic recording media based on poly(N-epoxypropylcarbazole) films containing charge-transfer systems as photogeneration sites were studied, in which donor and acceptor molecules (or their fragments) either formed adducts between one another or were covalently bound by polymethylene spacer groups or by a system of conjugated π bonds. The recording media based on compounds with intramolecular charge transfer over a system of conjugated bonds for recording holograms using the photothermoplastic method exhibit an narrower intense spectral sensitivity band and a high holographic sensitivity. In these media, the effect of prolonged storage of latent image before the development of a hologram was revealed and explained.

A comparative analysis of the recording media based on poly‐N‐epoxypropylcarbazole films doped with cationic, anionic, and intraionic organic dyes has been carried out for the purposes of holographic interferometry. It is shown that in the case of application of intraionic dyes recording media have satisfactory information characteristics. The use of anionic and cationic dyes does not give a positive result because of the absence of the photoconductivity effect in the anionic dyes and of the high electrical conductivity of the films on increase of the temperature of the cationic dyes. The effect of long‐term storage of a latent image in the films with intraionic dyes makes it possible to use them for recording holograms with several exposures.

The intensities of the long wavelength absorption bands of symmetrical and unsymmetrical polycarbocyanines in polymer films are redistributed in a constant electric field. This redistribution depends in a regular manner on the chemical structure of the dyes. The spectroscopic effects are interpreted via a change in the probability of the vibronic transitions caused by redistribution of the electron density in the chromophore of the dye in the external electric field.

Electric current pulses passing through conducting SnO2:In2O3 (ITO) layers (used as electrodes in optoelectronic devices) on plane-parallel glass substrates produce depolarization of the transmitted light. This effect, which is probably related to changes in the structure of ITO layers as a result of Joule heating, can lead to distortions of the information field in the course of optical data transmission.

Unusual multimodal kinetics of diffraction efficiency in the cycle of hologram recording and erasing were observed in the recording media for the holographic photothermoplastic technique. It was shown that this effect is caused by competition between the simultaneous development of regular and random "frosty" surface reliefs of the photoconducting polymer film during the hologram development. The mechanism explaining the decrease of the maximal diffraction efficiency as compared to its calculated value is discussed.

Information properties of recording media for photothermoplastic techniques were investigated. The films consisted of oligomer composites based on carbazole containing co-oligomers of linear and radial structures with branching centers on silicon and germanium atoms. It was ascertained that the media based on the radial oligomers possessed high holographic sensitivity because of the high plasticity and its ability to accumulate volume electric charge during the exposure. Examples of practical applications of the investigated recording media are presented.

This paper discusses the spectral and photoconductive properties of films based on a co-oligomer of glycidylcarbazole with additives of croconium dye in comparison with similar films with squarylium, merocyanine, and cationic polymethine dyes. It is concluded that croconium dye, like merocyanine dye, belongs to the electron-nonsymmetric organic dyes. The possibility of using croconines as sensitizers of photothermoplastic holographic recording media for the near-IR region is demonstrated for the first time. The lower holographic sensitivity of recording media with croconium dye by comparison with squarylium and merocyanine dyes is associated with the presence of deep traps for charge carriers, which are formed by the molecules of an intraionic dye and are liberated when heated in the process of development of the holograms.