The chemical composition of silver nanoparticles surface obtained by initial metal evaporation and chemical reduction from silver salts was investigated by X-ray photoelectron spectroscopy method. Differences in electronic state of atoms of silver nanoparticles depending on the method of obtaining them are shown. The authors revealed that silver atoms of nanoparticles obtained by reduction from salts are in the covalent state. Positive chemical shift of the binding energy of Ag3d core level of silver nanoparticles in comparison with a bulk metal is fixed. The deviation of electronic properties of chemically synthesized silver nanoparticles from the properties of evaporated nanoparticles in the form of decrease of conductivity, the changes of valence band, kinetic energy of Auger lines and Wagner parameter was discovered. Small changes related to the influence of oxygen on the state of superficial silver atoms were observed in silver core level spectra. The nature of different adsorption states of oxygen on silver nanoparticles surface depending on their type and temperature was investigated. It is shown that molecular oxygen forms stabilize on silver surface in normal conditions. The increase of adsorption temperature up to 450 K and the use of evaporating nanoparticles leads to the appearance of O 1s lines of oxygen atoms with more ion character of bonds with silver atoms in spectrum.

Aerosol-assisted chemical vapor deposition (AACVD), a method for producing single-walled carbon nanotubes (SWCNTs) with the use of ethanol and ferrocene as the sources of carbon and a catalyst introduced into a reactor by means of an ultrasound nebulizer, is described. The influence of different parameters such as temperature, growth time, and catalyst precursor concentration on the diameter and chirality of SWCNTs is studied by optical absorption spectroscopy. The suggested technique makes the production of small-diameter SWCNTs (0.75–1.43 nm) with sufficiently stable chirality distribution close to the achiral structures.

Получены наночастицы и нанослои серебра методом восстановления из раствора и методом термического напыления. Наночастицы и нанослои Ag исследованы методами фотометрии и просвечивающей электронной микроскопии. Спектры оптического поглощения и пропускания проанализированы в рамках теории Ми и теории плазморезонансных колебаний. Вычислены значения N e - эффективной концентрации электронов проводимости, γ - коэффициента затухания плазмонных колебаний, NV - значения величины объема наночастиц в единице объема системы; из спектров оптического поглощения и пропускания получены значения λ max - длин волн в максимуме поглощения и пропускания полос плазмонного резонанса. Методом просвечивающей электронной микроскопии исследован фазовый состав и морфология частиц серебра. Nanoparticles and silver layers have been obtained from the solution by restoration method as well as thermal coating one. Nanoparticles and silver layers have been studied by photometry and x-rayed electron microscopy methods. The spectra of optic adsorption and passing have been analyzed in the framework of Mie theory and the theory of plasma resonance oscillation values: N e - effective concentration of electron conductivity, γ - attenuation coefficient of plasma oscillations, NV - values of the bulk amount of nanoparticles in the unit volume of the system have been calculated. Values λ max - wave lengths in adsorption maximum and passing of plasma resonance strips have been received from the spectra of optic adsorption and passing. Phase constitution and morphology of silver particles have been investigated by X-rayed electron microscopy method.

The investigation of the effect of sensitivity centers formation in AgBr octahedral microcrystals (MC) (111) at the ripening without sulfurcontaining additives (natural ripening) is carried out. It is established that the sensitivity centers formation occurs during the shape modification of МC AgBr (111) owing to the disparity of the chemical potential of microcrystal facets. It directly proves the silver nature of sensitivity centers at the microcrystals AgBr (111) ripening in explored conditions. The results of experiment on the change of the octahedral AgBr (111) МC photosensitivity (S) depending on the crystal sizes (d) are discussed. For the first time it is shown that the limited concentration of the growth centers of silver particles on the surface of AgBr (100) and AgBr (111) МC makes 10–10 sm that is comparable with the density of the surface states related to Brs ions on the kink sites. It allows to present these defects as the active centers of silver concentration.

Research of the found effect of photosensitivity level increase is carried out during maturing of microcrystals AgBr with octahedron facets (111) without addition of sulphur containing additives (own maturing). It is established, that formation of the sensitivity centers occurs during modification of the AgBr (111) microcrystal form owing to difference of chemical potentials of microcrystal sides. Thus, direct proofs of the silver nature of the sensitivity centers at maturing of AgBr (111) microcrystals in researched conditions are obtained. The reasons of absence of own maturing effect for AgBr microcrystals of a cubic facet (100) and flat AgBr (Т-МК) microcrystals are discussed.

The formation of sensitivity effect in AgBr (111) emulsion microcrystals without the addition of photographically active compounds, called by us, spontaneous ripening, is found out. The Ag-n sensitivity centers are formed during habit microcrystals modification at supersaturation in the system owing to the difference of chemical potentials of silver on the crystal surface mu(111)-mu(100). The efficiency of ripening process of AgBr (111) increases with the microcrystals sizes and achieves a maximum at d=0.9-1.2 mu m. This value can be compared to lengths of photoelectron diffusion pass in silver halides microcrystals and with optimal quantity of ionic conductivity for the formation of centers of the latent image. The influence of added Cd2+ on spontaneous ripening processes was investigated. At small concentrations (up to 0.1 mol.%), the additive Cd2+ does not hinder the process of modification of the surface and ripening of microcrystals. With concentration Cd2+ change up to 1 mol.%, the increase of velocity of ripening and reaching of maximal sensitivity at concentration Cd2+= 0.5 mol. % can be connected with optimal value of ionic conductivity for shaping centers of the latent image. The values of supersaturation, critical supersaturation, growth rate of MC AgBr (111) and size of a critical nucleus for our experiments of synthesis are spotted. It is shown, that in the used crystallization requirements the growth rate G is more than critical growth rate G(*), that probably results in shaping nonuniform crystal structure. Influence of Gibbs-Thomson effect on the process of spontaneous ripening of MC AgBr (111) are discussed. It is shown that the shaping of sensitivity in the process of spontaneous ripening of MC AgBr (111) is due to the result of modification of the form and habit change MC from (111) up to (100) and spherical form.

We have studied the formation of the development centers in composites of the silver bromide-nonsensitive materials under the action of electric field and temperature. The spontaneous emission activity of selected pyroelectrics (polycrystalline samples and single crystals) by measuring the spectra of thermoinduced photon and electron emission was investigated. The redistribution of charge carriers in composites of the type studied can be driven by the difference in the Fermi energy of the contacting materials and in the temperature dependence of this parameter. Information on the Fermi energy relations between some pyroelectric and AgBr microcrystals was obtained by the Kelvin method. All samples were examined under an electron microscope in order to determine the dimensions of microcrystals, their distribution, and the features of silver cluster formation on the surface of AgBr grains in the presence of pyroelectric microcrystals. We have obtained for the first time the data showing that information can be recorded in AgBr pyroelectric composites in the dark due to the spontaneous pyroelectric activity phenomenon. The formation of development centers (silver clusters) in the AgBr pyroelectric composites exposed to an electric field is a new effect that cannot be explained by the emission of light quanta or charge carriers from pyroelectric grains. A possible reason for the silver cluster formation on AgBr microcrystals under these conditions can be the AgBr surface modification related to displacement of the ion equilibrium in the contact region as a result of polarization of the pyroelectric.

The method X-ray photoelectron spectroscopy (XPS) explored a series of polymetin tiacarcocyanine dyes before and after adsorption on the surface of microcrystals (MC) AgBr. It is found out, that the mechanism of adsorption dyes consists in the binding formation of heterocyclic kernels sulfur atoms of dyes with atoms of a substrate.

The results of the chemical sensitization study of octahedral AgBr microcrystals with the sizes 0.75 - 1.3 mum in various modes of ripening are presented. Spontaneous sensitization (thermal ripening of emulsions without photographically active additives) has been investigated. The spontaneous sensitization is effected regardless of the type of gelatins during synthesis and chemical sensitization. The influence of both the pBr value of chemical ripening and the adsorption of stabilizers and gold ions on photographic characteristics of emulsions in modes of spontaneous and sulfur sensitization have been studied. The data obtained are compared with the results of the similar investigations carried out with the emulsions containing cubic microcrystals, as well as tabular microcrystals. The peculiarities of photosensitivity centre formation in AgBr (111) microcrystals are discussed in terms of ionic conductivity change during chemical ripening.

This paper presents data on the investigation of emulsion photographic characteristics with octahedral habit microcrystals (MC) (111) with the size d=0.19-1.8 μm in different regimes of chemical ripening, tabular microcrystals (T-MC) AgBrI (111), senthesized by controlled double-jet crystallization (CDJC) and small grained emulsion ripening. Data on MC AgBr (100) are also given. The process of sensitivity formation under emulsion ripening synthesized at pBr < 2.5 without the introduction of photographically active admixtures is discussed. Sensitivity formation characteristics are dealt with taking into account synthesis conditions and ionic conductivity change in the process of MC ripening.

AgBr-emulsions with tabular hexagonal microcrystals were synthesized according to the procedure including nucleation, twinning and double-jet crystallization. Parameters which defined tile results were established from crystallization theories, mathematical modes of mass crystallization and experimental results. The effects of some parameters were studied.

The method of dielectric losses offered van Biezen in an extremity 60-th [ 1], is widely used for a research of the ionic conductivity of the photoemulsion silver halide microcrystals (MC). According to the method, photoemulsion represents the heterogeneous system consisting of conducting silver halide grains, concluded to the insulating gelatine. With overlay of an external electrical field in a such system there is a dielectric dispersion. Complex dielectric permittivity s + i ", where c ' - usual dielectric permittivity, " tgö- the factor of dielectric losses. Frequent dependence of the dielectric losses factors defined by expression [2J: 8" (co) = (g - S) (1 + (cot) asin inx/2) I (1 + 2 (cot) cositoc/2 + (r) 2a) has a maxima under condition of cot 1 , where (s - )- residual between values of static and optical dielectric permittivity 0) - cyclic frequency of an external electrical field; the parameter 0 < oc < 1 , determines a scatter on times of relaxation; 't time of relaxation. The frequency of a maxima of dielectric losses (Fmax) is directly proportional of ionic conductivity ( r) silver halide MC: =Fmax(-E ) 2/q(8c-Eo) Where 81 - dielectric permittivity of gelatine, q- a volumetric long of silver halide. The researches which have been carried out per the last years, have shown, that the ionic conductivity of silver halide MC depends on a number of the factors, such as habit and size of microcrystals, pAg of a solution of synthesis, addition of photogfraphic active substances. From here explicitly follows, that the change of a state of the microcrystal's surface, owing to various conditions of synthesis and adsorption of active substances influences the photographic characteristics emulsion, and also changes of the interstitial silver ions concentration -main carriers of a charge in the silver halide, which, as is known, plays the important role in the generation of the latent image centers.