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12 results on '"N.A. Davidenko"'

1. Polarization holography in azobenzene polymeric films prepared using the new chemical method

Author

N.A. Davidenko, I.I. Davidenko, V.V. Kravchenko, V.A. Pavlov, V.V. Tarasenko, and N.G. Chuprina

Subjects
polarization holography, photophysical properties, isomerization, recording material, azobenzene, Physics, QC1-999
Abstract

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.

Published
2020
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2. New material based on polyurethane doped with azobenzene dyes in recording media for dynamic polarization holography

Author

N.A. Davidenko, I.I. Davidenko, M.Yu. Sokolov, A.N. Gonchar, E.V. Mokrinskaya, S.L. Studzinsky, V.A. Pavlov, V.V. Tarasenko, L.S. Tonkopieva, and N.G. Chuprina

Subjects
azobenzene, holography, recording medium, polymeric composites, Physics, QC1-999
Abstract

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.

Published
2020
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3. List of contributors

Author

Shaikh Ziauddin Ahammad, Asad Ahmad, Iffat Zareen Ahmad, R. Alagirusamy, S. Wazed Ali, M.P. Quiroga Argañaraz, Ameer Azam, Bartosz Babiarczuk, Santanu Basak, G. Benítez, Modou Beye, Adam Blake, Beata Borak, Naveen Ashok Chand, James Chong, N.G. Chuprina, Gustavo Marques da Costa, Luiz Pereira da Costa, Apurba Das, I.I. Davidenko, N.A. Davidenko, Babacar Dieng, Djicknoum Diouf, Rahul R. Gadkari, L.M. Gassa, Jolanta Gąsiorek, Iain Hosie, Chaudhery Mustansar Hussain, Nur Atirah Ibrahim, Bhuvana Kannan, Manish Kaushik, Justyna Krzak, Mohammed Kuddus, Dinesh Kumar, Pablo Lepe, Israel López, Amadou S. Maiga, E.V. Mokrinskaya, Sukanchan Palit, V.A. Pavlov, Sapna Raghav, J.M. Ramallo-López, A. Rubert, R.C. Salvarezza, Joydip Sengupta, Mohd Shabbir, Mohammad Shahadat, Akshay Shukla, Santosh Bahadur Singh, Anna Szczurek, Heena Tabassum, M.E. Vela, Jessica Vidales-Herrera, Vinita Vishwakarma, Praveen Kumar Yadav, Muhammad Abbas Ahmad Zaini, E. Zelaya, and Hanyue Zheng

Published
2020

4. Polymeric compositions having near IR photoconduction

Author

N.A. Davidenko

Subjects
Materials science, Chemical engineering, Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials
Published
2004

8. Spin conversion and electric field effect on photoluminescence in amorphous molecular semiconductors doped with ionic dyes

Author

N.A. Davidenko and Alexander A. Ishchenko

Subjects
Photoluminescence, Dopant, Chemistry, Photoconductivity, Carrier generation and recombination, Doping, Physics::Optics, General Physics and Astronomy, Photochemistry, Amorphous solid, Condensed Matter::Materials Science, Intersystem crossing, Electric field, Physics::Chemical Physics, Physical and Theoretical Chemistry
Abstract

For poly-N-epoxypropylcarbazole films doped with a cationic polymethine dye, the photoconductivity and the effect of an external electric field on photoluminescence intensity in the dopant absorption region have been found to depend on the nature of a colorless dye counter-ion. These effects have been accounted for by a changed probability of an intersystem crossing in dye ion pairs and photogenerated electron–hole pairs. The spin conversion rate has been related to the degree of photoluminescence quenching in an external electric field.

Published
1999

10. On the influence of electron localization radius in a charge-transfer complex on photogeneration efficiency of current carriers in carbazole-containing semiconductors

Author

N.G. Kuvshinsky, N.A. Davidenko, and V.V. Reshetnyak

Subjects
chemistry.chemical_classification, Biophysics, Analytical chemistry, Electron, Electron hole, Electron acceptor, Condensed Matter Physics, Charge-transfer complex, Acceptor, Electron localization function, chemistry, Chemical physics, Charge carrier, Physical and Theoretical Chemistry, Absorption (electromagnetic radiation), Molecular Biology
Abstract

Measurements have been made, in thin films of poly-N-epoxypropylcarbazole, of the absorption coefficient, the activation energy of photogeneration and the photogeneration efficiency of charge carriers as functions of the concentrations of electron acceptors from the fluorene series. They have demonstrated a correlation between the localization radius of the excess electron in an acceptor molecule and the activation energy of photogeneration within the absorption region of a charge-transfer complex.

Published
1990

11. The influence of radical-anion electron density distribution on the dissociation efficiency of a bound electron-hole pair in carbazole-containing semiconductors

Author

L.I. Savransky, V.V. Reshetnyak, N.G. Kuvshinsky, V.L. Sheptun, and N.A. Davidenko

Subjects
chemistry.chemical_classification, Electron density, business.industry, General Physics and Astronomy, Activation energy, Electron hole, Electron acceptor, Photochemistry, Molecular physics, Electric charge, Dissociation (chemistry), Ion, Semiconductor, chemistry, Physics::Chemical Physics, Physical and Theoretical Chemistry, business
Abstract

The spectral dependence of the absorption coefficient, activation energy of photogeneration and current carrier photogeneration efficiency on the concentration of electron acceptors in the fluorene series in thin films of poly-N-epoxypropylcarbazole were measured. The effective atomic charges in the radical anions of the electron acceptors are calculated by the method of MOLKAO-MNDO. The energy of electrostatic interaction of the point charge hole with the effective charges of the radical anion is similar to that of the distributed electron charge whose probability is described by an axially symmetric wavefunction. This electrostatic interaction energy corresponds to the activation energy of photogeneration of current carriers at the site of the complex exhibiting absorption with charge transfer.

Published
1990

12. Electric and Photophysical Properties of Holographic and Electroluminescent Mediums Based on Amorphous Molecular Semiconductors

Author

Alexander A. Ishchenko, N. G. Kuvshinsky, and N.A. Davidenko

Subjects
Materials science, Semiconductor, business.industry, Electric field, Photoconductivity, Doping, Optoelectronics, Charge carrier, Electroluminescence, business, Holographic interferometry, Amorphous solid
Abstract

The results of investigations of electric and photophysical properties of the films of amorphous molecular semiconductors doped with different sensitizers of photoconductivity for visible light are discussed. Such films are used in the electrography, holography and electroluminescent devices. The general regularities of charge carriers transport, of electron-hole pair formation, of charge carriers recombination are ascertained. Examples of the holographic recording mediums as well as mediums for electroluminescent devices are presented.

Published
2003

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