Photoelectric and photorefractive properties of polyvinylcarbazole composites with graphene in the visible spectral range

The photoelectric and photorefractive characteristics of polyvinylcarbazole (PVK) composites with 0.15 wt % graphene at a wavelength of 532 nm have been measured. The dependence of the quantum efficiency of generation of mobile charge carriers as determined from the photocurrent is well approximated by the Onsager equation calculated accurate to E (0) (3) for the quantum yield of thermalized electron-hole pairs of phi(0) = 1 and their initial separation radius of r (0) = 10.9 . The long-wavelength edge of optical absorption for PVK lies at 365 nm. Thus, the photogeneration of mobile carriers during illumination of the composite at 532 nm is due to photoexcitation of graphene. The measurement of the photorefractive properties has revealed that the two-beam coupling gain coefficient is I" = 50 cm(-1) at E (0) = 150 V/mu m and equal intensities of incident beams. It has been found that at E (0) = 83.3 V/mu m, the two-beam coupling gain coefficient increases from 8 to 14 cm(-1) as the ratio of incident beam intensities I (1)(0)/I (2)(0) increases from 1 to 2.4

Near-field mapping of electrochemical properties of Polyaniline

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Photoelectric, nonlinear optical, and photorefractive properties of polymer composites including carbon nanotubes and cyanine dyes

The effect of cyanine dye additives on the photoelectric, nonlinear optical, and photorefractive properties of polyvinyl carbazole composites based on closed single-walled carbon nanotubes has been investigated. It has been found that these characteristics are affected by the dye in which the lowest unoccupied molecular orbital (LUMO) lies below the level of the photoexcited nanotube. The addition of this dye to the composite leads to a 14-fold increase in the quantum efficiency of the generation of mobile charge carriers under irradiation by a laser (1064 nm) in the absorption region of the nanotubes. Moreover, the addition of the dye to the composite decreases the third-order susceptibility χ (3) , presumably, due to the opposite orientations of dipoles of the dye and the nanotube upon adsorption of the dye on the nanotube. The addition of the dye to the composite also provides a twofold increase in the two-beam photorefractive amplification factor of the laser beam with a wavelength of 1064 nm. The obtained values of the two-beam photorefractive amplification factor reach 120 cm -1 . \ua9 2013 Pleiades Publishing, Ltd

Photoelectric, nonlinear optical, and photorefractive properties of polyvinylcarbazole composites with graphene

Polyvinylcarbazole (PVK) composites containing graphene in an amount of somewhat less than 0.15 wt % exhibit third-order dielectric susceptibility due to the presence of graphene, as well as photoelectric and photorefractive sensitivity at 1064 nm. The photorefractive (PR) effect is known to occur in a polymer composite that possesses both photoelectric sensitivity and nonlinear optical properties. The photoelectric, nonlinear optical, and PR properties of PVK composites with graphene have been considered in this paper

No Time Like the Present: Thinking About the Past and the Future Is Related to State Dissociation Among Individuals With High Levels of Psychopathological Symptoms

Several short-term pathways have been implicated in relation to dissociative experiences, among them are daily stress, sleepiness, and rumination. In addition, it has been claimed that mechanisms contributing to dissociative experiences may differ, according to specific psychopathological symptoms. Accordingly, this study had two aims. The first was to sample moment-to-moment increases or decreases in current stress, sleepiness, and rumination, in order to assess their temporal relations with state dissociation. Rumination was broken down to its basic two subcomponents: the negative value of the thoughts and thinking about the past (in comparison to present or future), in order to differentiate it from other repetitive thought patterns (e.g., worry). The second goal was to explore whether depression, anxiety, and obsessive–compulsive symptoms may moderate the links between the three mechanisms and specific state dissociation scales [specifically, depersonalization-derealization (DEP-DER) and absorption (ABS)]. Ninety-nine undergraduate students completed trait questionnaires and then answered state items four times a day for 4 days. These experience sampling data were analyzed using multilevel linear modeling (MLM) with Level 1 state measurements and Level 2 demographic and trait variables of the participants. Moments of stress, sleepiness, thinking about the past and negative thoughts were all associated both with state DEP-DER and with state ABS. Dissociation, negative thinking, stress, and sleepiness were positively associated with moments of thinking about the past and the future but inversely associated with moments of thinking about the present. Finally, in accordance with our expectations, the links between DEP-DER and hypothesized mechanisms were mostly moderated by depression and anxiety symptoms, whereas the links between ABS and hypothesized mechanisms were moderated mainly by obsessive–compulsive symptoms. Our findings are in accordance with literature on the efficacy of mindfulness as well as the maladaptive correlates of mind-wandering, as they suggest that dissociative detachment from one’s present occupation is associated with decreased well-being

Essential Role of Correlations in Governing Charge Transport in Disordered Organic Materials

The transport of photoinjected charges in disordered organic films is often interpreted using a formula based on a Gaussian disorder model (GDM) that neglects spatial correlations due to charge-dipole interactions, even though such correlations have recently been shown to explain the universal electric field dependence observed in these systems. Based on extensive computer simulations of a 3D disorder model that includes such correlations, we present a new formula for analyzing experiments that accurately describes transport in these materials

Near-field mapping of spectroelectrochemical properties of polyaniline

We combine in this work the measurement of local optical transmission in the near-field with the mapping of the third harmonic generation of semiconducting polymer samples. The use of a linear method with the scanning near-field optical microscope (SNOM) and a nonlinear method with the Third Harmonique Generation (THG) microscope reveal the variation and the nature of the nanomorphology of doped polyaniline thin films

Исследование матричной полимеризации анилина в присутствии смесей полимерных сульфокислот и свойств образующихся интерполимерных комплексов

The polymerization of aniline in the presence of mixtures of polymer sulfonic acid <http://lingvo.yandex.ru/en?text=sulfonic acid&st_translate=on&lang_from=en&lang_to=ru&dict=Medical>s has been studied. It was shown dominating influence of rigid polyacid on polymerization kinetics and electronic structure of formed polyaniline.Изучена полимеризация анилина в присутствии смесей полисульфокислот, различающихся гибкостью цепи макромолекулы. Показано доминирующее влияние жесткоцепной поликислоты на кинетику полимеризации и электронную структуру образующегося полианилина