Silver Chloride Microcrystals Research Articles

Electronic trap effect of spectral sensitizing dye adsorbed on the surface of silver chloride

Using spectral sensitizing technology，silver halide microcrystals can be sensitized to the visible light region. The spectral sensitizing technology is important to the modern information recording and storage，solar energy transfer and storage, and the photoelectronic devices. The photoelectron decay characteristic of silver chloride microcrystals，which is adsorbed with green sensitizing cyanine dye，is studied by microwave absorption and dielectric spectrum detection technology. The model of photoelectron decay is set up. Electron trap effect of the dye in the silver halide surface is analyzed based on the photoelectron decay model and the photoelectron decay characteristic. The results show that when the mono-molecular dye is adsorbed on the surface，shallow electron traps are created; when the J-aggregated dye is adsorbed on the surface，deep electron traps are created. The critical dose of dye that seperates the shallow electron trap and deep electron trap effects is 0.2ml of dye (with concentration of 5.0mg/ml) per 40g AgCl emulsion.

Luminescence of silver chloride microcrystals upon photoexcitation by different methods

The luminescence spectra of AgCl microcrystals were measured in two different regimes: in the regime of excitation of stationary luminescence and in the regime of photostimulated burst of luminescence. Differences between the spectra of stationary luminescence and the spectra of photostimulated-luminescence burst in the range between 430 and 590 nm have been found. The luminescence spectra are complex; the ratio of intensities for elementary components changes with the technique of excitation. Differences in the form and composition of complex luminescence bands obtained under different conditions of registration are attributed to the recombination interaction of the luminescence centers. It is shown that analysis of the dependences of intensity ratios for the elementary components of a complex luminescence band on the exciting-radiation intensity allows one to evaluate the mechanism of recombination in elementary bands provided that the mechanism is known for at least one luminescence band.

Magnetic resonance analysis of a hydrated Rh 2+ complex in silver chloride microcrystals

Irradiation of Rh 3+ doped AgCl microcrystals with UV-light or X-rays leads to the formation of three distinct Rh 2+ complexes with slightly different g values (R4, R5 and R6). The microscopic structure of the R4 complex has been studied with X and Q band electron paramagnetic resonance and X band electron nuclear double resonance. The centre was found to have nearly axial symmetry. A powder electron nuclear double resonance (ENDOR) analysis revealed the presence of two or four nearby protons in the plane perpendicular to the main axis of the Rh 2+ complex, indicating that two Cl − ligands in this plane are replaced by OH − or H 2O molecules.

Mass crystallization of silver chloride microcrystals

In this work some problems on silver chloride isometric and flat crystals crystallization are considered. It is shown that the synthesis of monosize isometric microcrystals should proceed in the absence of a silver chloride solvent. The flat silver chloride microcrystals, in the absence of growth modifiers, are formed by a coalescent mechanism.

Mass crystallization of silver chloride microcrystals

In this work some problems on silver chloride isometric and flat crystals crystallization are considered. It is shown that the synthesis of monosize isometric microcrystals should proceed in the absence of a silver chloride solvent. The flat silver chloride microcrystals, in the absence of growth modifiers, are formed by a coalescent mechanism. Microsc. Res. Tech. 42:145–147, 1998. © 1998 Wiley-Liss, Inc.

In situ HREM study of electron irradiation effects in AgCl microcrystals

Cubic silver chloride microcrystals (size between 10 and 50 nm) were investigated with high-resolution electron microscopy. The print-out effect that occurs due to reaction with the electron beam was used to investigate the orientational relationship between the AgCl crystal and the Ag particles that are formed on the AgCl crystal. The particles are found to retain the same cubic directions as the AgCl crystal with a macroscopic form of a truncated octahedron.

In SITU HREM study of electron irradiation effects in AgCl microcrystals

Abstract Cubic silver chloride microcrystals (size between 10 and 50 nm) were investigated with high-resolution electron microscopy. The print-out effect that occurs due to reaction with the electron beam was used to investigate the orientational relationship between the AgCl crystal and the Ag particles that are formed on the AgCl crystal. The particles are found to retain the same cubic directions as the AgCl crystal with a macroscopic form of a truncated octahedron.

Influence of hydrodynamic conditions on the controlled double-jet precipitation of silver halides in mechanically agitated systems

The controlled double jet precipitation of silver halides from a homogeneous reaction in the liquid phase involves a chemical reaction which produces supersaturation, nucleation, and growth of crystals. Mixing influences all three of these processes. The mixing/stirring conditions play an important role in controlling the chemical composition, average grain size, and grain size distribution of formed particles. The purpose of this study was to determine the dependence of the mixing and stirring conditions on the controlled double jet precipitation of silver halides. Experiments were conducted in a flat-bottom crystallizer, a profiled bottom crystallizer, and a profiled bottom crystallizer equipped with a conical draft-tube. The average crystal diameter of the formed silver chloride microcrystals was independent of the crystallizer configuration if the frequency of revolution of the 50 mm diameter impeller was greater than 300 RPM. The variation coefficient decreased if the controlled double jet precipitation was carried out in a crystallizer with a profiled bottom and/or a draft-tube.

Formation of Silver Chloride Microcrystals by Reaction of Silver Alginate Films with Hydrochloric Acid

Formation of Silver Chloride Microcrystals by Reaction of Silver Alginate Films with Hydrochloric Acid

Halide composition profiles in silver halide microcrystals

We investigated the halide composition depth profile in micron-size silver halide microcrystals using x-ray photoelectron spectroscopy in conjunction with ion etching. Using a double-jet technique, intentionally mixed halide microcrystals were precipitated such that the thermodynamic equlibrium of the solution-solid interface was maintained. Microcrystals precipitated using halide-conversion techniques showed a compositional variation. In bromide-converted silver chloride microcrystals, after an initial decrease from the surface value, the chloride ion concentration increased smoothly with depth, leveling off (at about 100 nm below the original surface) to a value about 10% higher than in the surface region. X-ray diffraction patterns from these microcrystals show a skewed line shape for the halide-converted materials. A graded-band-gap model is proposed which may account for the tendency of the halide-converted crystals to form an internal latent image.