L. I. Kostenko

Sensitization of photosensitivity of photothermoplastic holographic recording media by metal (Zinc, Dysprosium) mono-and diphthalocyanines in the presence of praseodymium sesquioxide

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.

Negative photoconductivity of ferrocenyl-containing oligomer films with a merocyanine dye

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.

Optically and chemically amplified photoresists based on poly(hydroxyaminoester)s

Processes for both optical and autocatalytic chemical amplification of a latent image have been realized in the polymer donor poly(hydroxyaminoester) in the presence of the electron acceptor hexabromodimethylsulfone and the chemical sensitizes dimethylaminobenzaldehyde. This resulted in a negative photoresist with a sensitivity as high as 0.2–0.5 mJ cm–2.

Electric and Photoconductivity of Polymer Composites Containing Heteropolynuclear M(II)/Cr(III) Complexes in the Presence of Additives with Different Electron Donor-Acceptor Properties

Electro-and photoconductive properties of polymer composites doped with heteropolynuclear M(II)/Cr(III) (M = Zn, Co, Mn) complexes were studied in the presence of organic additives with different electron donor-acceptor properties: anthracene, fullerene C60, terephthaloyldianthracene, and bis(biphenyl)chromium(I) fulleride (Ph-Ph)2CrC60. Upon excitation of the d-d transition in Cr(III), the magnitude of inner photoelectric effect in composite films examined is the highest for the Zn(II)/Cr(III) complex and increases in the series of additives anthracene, fullerene C60, terephthaloyldianthracene, (Ph-Ph)2CrC60. The use of the dopant (Ph-Ph)2CrC60 increases photocurrent by about two orders of magnitude.

Features of the photovoltaic properties of photosemiconductor film composites based on ferrocenyland carbazolyl-containing oligomer doped with a merocyanine dye

New photosensitive polymer film composites based on an oligomer containing ferrocenyl and carbazolyl moieties, doped with a merocyanine dye based on ferrocene and tetranitrofluorenone, have been created, and their photoelectric properties have been studied. It has been found that these composites possess photovoltaic properties. The mechanism and features of the photovoltaic effect in the test materials are discussed.

Photochemical recording of an image with nonlinear optical properties in polymer layers

The resistless process of the photochemical formation of nonlinear optical pattern in the polymer layer was elaborated. The illumination of the polymer donor-acceptor layers consisting of poly(hydroxyaminoester) as a donor and tetrabromomethane as an acceptor provides second harmonic generation (SHG) due to the photochemical formation of the Michlers hydrol blue like fragment (MHB+). The square root of the SH intensity, I0.5, linearly increases with the increase of exposure dose in region H <EQ 120 mJ cm-2. SHG is absent on unexposed areas of the same layer. SHG arises due to transformation of the geometry of MHB+ cation from centrosymmetric to noncentrosymmetric because of bond-length alternation under influence of Br counteranion.

Photochemical formation of nonlinear optical and photorefractive image in polymer layer

Abstract The paper is devoted to the development of the light-sensitive layers in which the image with nonlinear optical (NLO), photoelectric and photorefractive (PR) properties arises as a result of the photochemical reaction. Layers were obtained by using poly(hydroxyaminoether) (PHAE) containing electron-donor aromatic amino-groups in polymer chains doped with tetrabromomethane as an acceptor. The amino-groups and tetrabromomethane molecules form donor–acceptor complexes the photoexcitation of which induces electron transfer from the donor to the acceptor leading to the synthesis of a colored polycation product which possesses charge carrier photo-generating and NLO properties. Besides, these layers are electron-transporting. This allowed to obtain light-sensitive layers for recording NLO and PR images and pictures.

Photorefractive Properties of Photochemically Modified Poly(hydroxyaminoether)

The exposure of photosensitive poly(hydroxyaminoether)-based polymer compositions to light leads to the formation of an image with nonlinear optical and photoelectric properties and, hence, photorefractive behavior. Using the holographic birefringence technique, it was shown that the pumping of one of laser beams (signal beam) at the expense of the intensity of another (reference beam) takes place in the photochemically modified regions of the polymer layer. Unlike the majority of the previously studied photorefractive polymeric media, the beam-coupling gain coefficient Γ(cm–1) exceeds the absorption coefficient α(cm–1); i.e., the intensity of the signal beam after passing the layer becomes higher than that before the layer. A net internal gain, i.e. the difference Γ – α, of 117 cm–1is achieved at E0= 26 V/μm. The photorefractive effect is absent from the unexposed areas of the layer.