Detection of Ag<sup>2+</sup> in doped AgCl crystals by ESR

Höhne, M.; Stasiw, M.

doi:10.1002/pssb.19680250160

Cited by 16 publications

(8 citation statements)

References 2 publications

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“…1a the optically detected EPR spectrum is shown, which was observed at 95 GHz in the total luminescence of the AgCl crystal upon UV irradiation, with the magnetic field B parallel to one of the cubic axes 〈100〉 of the AgCl crystal. The transitions at 3.1572 and 3.3250 T correspond to resonances of the STH, with B 0 parallel to the distortion z -axis and B || x , y : g values g ||STH = 2.147 and g ⊥STH = 2.040, respectively, in agreement with previous studies [7–9]. The two lines at 3.3541 and 3.3865 T correspond to the low-field and high-field transitions of the STE, with B 0 parallel to the distortion z -axis: they are characterized by g ||STE = 2.014.…”

Section: Self-trapped Excitonssupporting

confidence: 91%

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

et al. 2010

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Silver halides have unique features in solid state physics because their properties are considered to be of borderline nature between ionic and covalent bonding. In AgCl, the self-trapped hole (STH) is centered and partly trapped in the cationic sublattice, forming an Ag2+ ion inside of a (AgCl6)4− complex as a result of the Jahn–Teller distortion. The STH in AgCl can capture an electron from the conduction band forming the self-trapped exciton (STE). Recent results of a study of STE by means of high-frequency electron paramagnetic resonance, electron spin echo, electron–nuclear double resonance (ENDOR) and optically detected magnetic resonance (ODMR) are reviewed. The properties of the STE in AgCl crystals, such as exchange coupling, the ordering of the triplet and singlet sublevels, the dynamical properties of the singlet and triplet states, and the hyperfine interaction with the Ag and Cl (Br) nuclei are discussed. Direct information about the spatial distribution of the wave function of STE unpaired electrons was obtained by ENDOR. From a comparison with the results of an ENDOR study of the shallow electron center and STH, it is concluded that the electron is mainly contained in a hydrogen-like 1s orbital with a Bohr radius of 15.1 ± 0.6 Å, but near its center the electron density reflects the charge distribution of the hole. The hole of the STE is virtually identical to an isolated STH center. For AgCl nanocrystals embedded into the KCl crystalline matrix, the anisotropy of the g-factor of STE and STH was found to be substantially reduced compared with that of bulk AgCl crystals, which can be explained by a considerable suppression of the Jahn–Teller effect in nanoparticles. A study of ODMR in AgBr nanocrystals in KBr revealed spatial confinement effects and allowed estimating the nanocrystal size from the shape of the ODMR spectra.

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Section: Self-trapped Excitonssupporting

confidence: 91%

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

et al. 2010

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“…The commercial electron spin resonance spectrometer ERS-XQ from the Akademiewerkstatten fiir Forschungsbedarf permitted an extension of the measurements compared with [3]. The structure of the spectrum due t o the chlorine isotope effect could be observed because of the improved signal-to noise ratio, allowing the determination of the appropriate hyperfine parameters.…”

Section: Methodsmentioning

confidence: 99%

“…Recently it was reported in a short note [3] that Ag2+ centres can be produced in pre-irradiated AgCl crystals doped with Ag,S or Ag,Se. An essential difference to the Ag2+ centres in alkali chlorides is the fact that in AgCl the hole is not localized a t an impurity ion, but a t a cation of the host lattice.…”

Section: Introductionmentioning

confidence: 98%

ESR Detection of Self‐Trapped Holes in AgCl

Höhne¹,

Stasiw²

1968

Physica Status Solidi (b)

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Ag2+ centres are produced in doped and appropriately treated AgCl crystals by irradiation with blue light a t 20 OK. It is shown that the only purpose of the preceding treatment is to create a high concentration of electron traps. I n chalcogen doped crystals (AgCl :S, Se, Te) electron traps are formed by pre-irradiation with blue light above 120 " K ; in iron doped crystds the incorporated Fe2+ ions are converted to Fe3+, acting as traps, either by irradiation a t 20 "C or by annealing in chlorine gas. As the paramagnetic data of the localized Ag2+ centres are independent of the kind of the impurity, one must conclude that the hole is trapped in the undisturbed lattice.Ag2+-Zentren werden in dotierten und geeignet behandelten AgC1-Kristallen durch Bestrahlung mit blauem Licht bei 20 O K erzeugt. Es wird gezeigt, daB die Aufgabe der Vorbehandlung allein darin besteht, eine hohe Konzentration von Elektronenfallen zu schaffen.I n chalkogen-dotierten Kristallen (AgC1: S, Se, Te) wird die Bildung von Elektronenfallen durch Vorbestrahlung mit blauem Licht oberhalb von 120 OK bewirkt ; in eisen-dotierten Kristallen werden die eingebauten Fez+-Ionen entweder durch Bestrahlung bei 20 "C oder durch Tempern in Chlorgas in Fe3+ umgeladen, das als Fanger dient. Da die paramagnetischen Daten der lokalisierten Agz+-Zentren unabhangig von der Art des Zusatzes sind, muB man auf einen Einfang der Defektelektronen im ungestorten Gitter schlieSen.

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“…Figure 2 shows EPR spectra of microcrystals doped with [IrCl 5 (thiazole)] 2À (trace (c)) and [IrCl 6 ] 3À (trace (b)) after exposure to light of 365 nm wavelength at 15 K. The spectra are characteristic for an unpaired electron trapped in an Ir 5d z 2 orbital. The EPR signal between 300 and 340 mT is due to the Ag þ self-trapped hole [13]. [IrCl 5 (thiazole)] 3À exhibits a considerable non-axiality of the g-matrix.…”

Section: [Ircl 5 (Pyrazine)] 2à and [Ircl 5 (N-methylpyrazine)] 1àmentioning

confidence: 99%

Defects in the silver halide photographic process

Pawlik

Eachus

Baetzold

et al. 2002

Radiation Effects and Defects in Solids

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The imaging efficiency of today's photographic film and paper is influenced in a variety of ways. Among them, the incorporation of dopants is widely used to increase efficiency, control contrast or improve imaging deficiencies such as reciprocity law failure. Transition metal-organic ligand dopants are attractive because the organic ligand influences the photographic properties. Experimental studies have shown that many of these dopants incorporate well into the silver halide microcrystal even with large organic ligands. In this paper, experimental and computational results are presented on a variety of Ir-OL dopants in AgCl where OL is a small nitrogen and=or sulfur-containing heterocycle. Electron paramagnetic resonance methods provide information about the electronic structure, electron trapping properties and the stability of the electron trap state. These results are complemented by ab initio studies that give information about the optimum structure, charge compensation and the possibility of electron and hole trapping.

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Detection of Ag²⁺ in doped AgCl crystals by ESR

Cited by 16 publications

References 2 publications

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

ESR Detection of Self‐Trapped Holes in AgCl

Defects in the silver halide photographic process

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Detection of Ag2+ in doped AgCl crystals by ESR

Cited by 16 publications

References 2 publications

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

ESR Detection of Self‐Trapped Holes in AgCl

Defects in the silver halide photographic process

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Detection of Ag²⁺ in doped AgCl crystals by ESR