Individual formation parameters of charged point defects in ionic crystals: Silver chloride

Hudson, R. A.; Farlow, G. C.; Slifkin, Lawrence

doi:10.1103/physrevb.36.4651

Cited by 33 publications

(4 citation statements)

References 24 publications

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“…Besides conductivity measurements, an experimental proof of the course of the potential in the space-charge region may be performed by studying the distribution of small amounts of an aliovalent tracer [31,32] dissolved in the crystal. In general, the above calculations may be further extended to the extrinsic case, i.e.…”

Section: Discussionmentioning

confidence: 99%

Theory of the Frenkel–Debye boundary layer at the (111) surface of pure CaF₂

Dabringhaus

Бутман

2003

J. Phys.: Condens. Matter

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The present paper is concerned with a theoretical study of the properties of the Frenkel-Debye boundary layer at the (111) surface of pure (undoped) CaF 2 , a crystal with anti-Frenkel defects, i.e. with anion vacancies and interstitials. The study is based on theoretical determinations of the adsorption energies of the fluorine ion at the terrace, step and kink sites on the surface, which are, together with the assumption of experimental step distances and theoretical kink concentrations, necessary pre-requisites for a quantitative description of the surface charge compensating that of the space-charge region. The results show that, for realistic surface conditions, the surface and space charges, and with them the potential between surface and bulk, are reduced considerably compared with those for an unlimited number of accessible surface sites. Nevertheless, on approaching the surface a strong increase in the anion vacancy concentration against that of the bulk still exists, which should lead to an increased ion conductivity in near-surface regions and thin fluorite layers.

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Section: Discussionmentioning

confidence: 99%

Theory of the Frenkel–Debye boundary layer at the (111) surface of pure CaF₂

Dabringhaus

Бутман

2003

J. Phys.: Condens. Matter

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“…On the other hand, a small fraction of silver cations is omitted from its usual position in the lattice and (in order to maintain electrical neutrality) it is placed within a non-lattice, interstitial position, creating defects (called Frenkel pairs) [19,20]. Interstitial silver ions are found mainly within the bulk of the crystal but due to their small size, they can move throughout the cubic lattice structure [21]. Since AgCl crystals have a direct band gap of 5.15 eV (241 nm) and an indirect band gap of 3.25 eV (382 nm) [22], they can only absorb UV light.…”

Section: Sensing Mechanismmentioning

confidence: 99%

Paper-Based Device for Sweat Chloride Testing Based on the Photochemical Response of Silver Halide Nanocrystals

et al. 2021

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A new method for the determination of chloride anions in sweat is described. The novelty of the method relies on the different photochemical response of silver ions and silver chloride crystals when exposed to UV light. Silver ions undergo an intense colorimetric transition from colorless to dark grey-brown due to the formation of nanosized Ag while AgCl exhibits a less intense color change from white to slightly grey. The analytical signal is obtained as mean grey value of color intensity on the paper surface and is expressed as the absolute difference between the signal of the blank (i.e., in absence of chloride) and the sample (i.e., in the presence of chloride). The method is simple to perform (addition of sample, incubation in the absence of light, irradiation, and offline measurement in a flatbed scanner), does not require any special signal processing steps (the color intensity is directly measured from a constant window on the paper surface without any imager processing) and is performed with minimum sample volume (2 μL). The method operates within a large chloride concentration range (10–140 mM) with good detection limits (2.7 mM chloride), satisfactory recoveries (95.2–108.7%), and reproducibility (<9%). Based on these data the method could serve as a potential tool for the diagnosis of cystic fibrosis through the determination of chloride in human sweat.

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“…Many other experimental observations are in agreement with the space-charge layer model, including impedance spectra of composite or polycrystalline materials, 83 temperature and particle-size dependencies of conductivity, 44 wetting experiments, change of majority defect in TlCl composites, 84 and dopant concentration profiles at interfaces in the system AgCl-MnCl 2 . 85 (c) Percolation Model: Although the analytical Eq. (17) is in good agreement with the experimental data for many composite systems in an intermediate range of composition, a linear relation cannot describe the behavior near critical points.…”

Section: (B) Analytical Expressions Of Conductivitymentioning

confidence: 99%