N. A. Davidenko

Information media based on electron donor oligomers with different structures

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.

Photosemiconducting properties of holographic media based on ferrocenyl-containing cooligomers of glycidyl carbazole with these oligomers sensitized by organic dye

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.

Croconium dye as a sensitizer of photothermoplastic holographic media for the near-IR region

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.

Effects of the nature of the anion of cationic polymethine dyes on the photovoltaic properties of polymer photosemiconductor composites

It has been found that the nature of the anion of cationic polymethine dyes in polymer solar cells affects photo-emf. A study of the spectral and luminescent properties has revealed that polymethines in these cells form contact ion pairs. It has been shown that the difference in behavior between the anions is determined by their ability for photoinduced electron transfer in these pairs.

Information media based on electron-donor oligomers

Routes for designing hole-conducting organic polymers for use in photoelectric solar-energy converters and light emitters and primarily for recording, storage, and processing of optical information are considered. New carbazole-containing radially tetrasubstituted silanes and germanes are described. It is shown that the information characteristics of holographic recording media based on oligomer compositions substantially depend on the shapes of the oligomer macromolecules.

Synthesis and Electrooptical Properties of Metal-Containing Azopolymers

We propose new structures of polymeric composites with changeable optical characteristics (transmission and/or reflection of polarized light) under the influence of magnetic and/or electric fields. The new monomers 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-azobenzene, 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-nitroazobenzene,and 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-diethylamino-azobenzene, their complexes with Co, and polymers based on their base are synthesized. The influence of the electric field on the absorption spectra of films of the new metal-containing azopolymers is investigated. The effect of an electric field on the transmission of a linearly polarized light through the films is revealed. This effect is determined by the re-orientation of the dipole moments of azobenzene groups which is induced by a polarized light under the action of an electric field. The increase of the dipole moments of azobenzene groups due to the introduction of donor and acceptor substituents reduces the influence of Co ions on the electrooptical properties of polymeric films.

Sensitization of Photosemiconducting Properties of Holographic Recording Media Based on Glycidylcarbazole Cooligomers by Organic Dyes

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.

Photoconductivity of organic polymer films doped with porous silicon nanoparticles and ionic polymethine dyes

Features of electrical conductivity and photoconductivity of polyvinylbutyral films containing porous silicon nanoparticles and similar films doped with cationic and anionic polymethine dyes are studied. Sensitization of the photoelectric effect by dyes with different ionicities in films is explained by the possible photogeneration of holes and electrons from dye molecules and the intrinsic bipolar conductivity of porous silicon nanoparticles. It is assumed that the electronic conductivity in porous silicon nanoparticles is higher in comparison with p-type conductivity.

Photoconductivity of Polymeric Composites Doped with Porous Silicon Nanoparticles and Additions of Ionic Polymethine Dyes of Different Types

Features of the electrical conductivity and the photoconductivity of polyvinylbutyral films containing silicon nanoparticles and similar films doped with cationic and anionic polymethine dyes are studied. Sensitization of the photoelectric effect by dyes with various ionicities in films is explained by the possible photogeneration of holes and electrons from dye molecules and the intrinsic bipolar conductivity of silicon nanoparticles. It is assumed that the electronic conductivity in silicon nanoparticles is higher as compared with that in nanoparticles with p-type conductivity.

Influence of ionic forms of polymethine dyes on the photoconductivity of doped films of poly-N-epoxypropylcarbazole

Abstract The features of photoconductivity of the films of poly-N-epoxypropylcarbazole doped with cationic, squarylium and merocyanine dyes are investigated. Under temperature growth starting from room the photoconductivity of the films with cationic and squarylium dyes increases more strongly as compared to the similar films with merocyanine. It was explained by a destruction of structural traps close to electrically charged fragments of dyes. In contrast to the films of the first two types, the photoconductivity of the films with merocyanine dye depends sublinearly on incident light intensity due to an effective bimolecular charges recombination.