Luminescent processes elucidated by simple experiments on ZnS

Schwankner, R.; Eiswirth, M.; Venghaus, H.

doi:10.1021/ed058p806

Cited by 2 publications

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“…Das macht ihre radiometrische Charakterisierung notwendig, um den Umgang mit ihnen aus strahlenhygienischer Sicht bewerten zu können. Man muss nur mit einem Geiger-Müller-oder einem Proportionalzählrohr Antiquitäten-und Flohmärkte durchstreifen: Damit kann man Uran durch seine radiogenetisch ständig nachproduzierten, kurzlebigen b-strahlenden Töchter aufspüren [11]. Dabei entdeckt man drei weitere Typen von radioaktiven Gläsern und darüber hinaus auch die uranhaltigen: 1. bund g-strahlende Objekte mit typischen Kaliumgehalten zwischen einem und zwanzig Gewichtsprozent.…”

Section: Konservatorische Radiometrieunclassified

“…Auch die hier vorgestellten Uranglaskompositionen lassen einfache, tragbare b-Zählgeräte ansprechen. Um sie vor Ort von den Spezies zu unterscheiden, die in den ersten drei Punkten beschrieben sind, reicht in vielen Fällen eine batteriebetriebene UV-A-Lampe [11]. Es kann allerdings sein, dass man die Fluoreszenz nur in einem dunklen Raum sicher erkennen kann (Abbildungen 6 bis 8).…”

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Strahlende Kostbarkeiten: Uran als Farbkörper in Gläsern und Glasuren

Schwankner

Eigenstetter²,

Laubinger³

et al. 2005

Physik in unserer Zeit

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Ein Streifzug mit einem einfachen Zählgerät über Flohmärkte zeigt, dass vor allem viele historische Gläser und Glasuren ihre prächtigen Farben dem Aktinidenelement Uran in seinen verschiedenen Oxidationsstufen verdanken. Eine kurze Geschichte dieser "nicht-nuklearen" Verwendung von Uran. Uran-Apothekerglas aus Wien im Kunst-und UV-Licht. Die Aktivität beträgt A'( 238 U) = 17000 Bq, demnach enthält es 0,4 Gew.-% an 238 U, seine g -Oberflächendosisleistung erreicht 200 nSv/h. Der relativ hohe Kupfergehalt der Glasmatrix (0,3 Gew.-%) schwächt die Uranyl-Fluoreszenz nur bedingt. Abb. 1 Teetasse glasiert mit Uranorange (UO 3-x ; g -Dosisleistung an der Oberfläche ≤ ≤ 60 nSv/h).

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Section: Konservatorische Radiometrieunclassified

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Strahlende Kostbarkeiten: Uran als Farbkörper in Gläsern und Glasuren

Schwankner

Eigenstetter²,

Laubinger³

et al. 2005

Physik in unserer Zeit

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“…Several models for the luminescent processes in ZnS based on semiconductor theory have been proposed (1,2,7,8). Whereas in oxide-type phosphors the luminescent transitions usually involve excited states of the activator and no charge transfer over lattice sites, the phosphorescence in ZnS usually arises from the radiative recombination of electrons and holes at defect levels located in the forbidden energy gap and may involve charge transfer.…”

Section: Processes Involvedmentioning

confidence: 99%

“…Other articles (1,2) have recently been published concerning phosphorescent ZnS materials. It is the purpose of this paper to discuss the optical properties of inorganic materials, doped ZnS as a specific system and to point out the chemical considerations that need to be made in the preparation of a phosphor.…”

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Preparation of a phosphor, ZnA:Cu2+

Suib¹,

Tauaka²

1984

J. Chem. Educ.

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Phosphorescence is a fascinating phenomenon that we encounter every day. This paper is an outgrowth of an experiment that we have used in an undergraduate advanced inorganic chemistry course tor swrral ).;an. The purpose of this experiment is to famlllnrize the student with methods and equipment not encountered in other chemistry laboratory courses. This particular experiment exposes a student to the preparation of a doped semiconductor, phosphorescence, gettering procedures, reducing atmospheres, and the use of a high temperature furnace with associated thermocouples, temperature controllers, and temperature-sensing devices. There are several variables that can he changed during the course of several semesters or from student to student such as the temoerature. the nature and concentration of the dopant, and Eharacterization methods. The principles of excited states. hand theorv. and the structure of solids like ZnS are . .presented in the corresponding lecture part of this course.Other articles ( 1 . 2 ) have recentlv been ouhlished concerning phosphore&nt ZnS materials: It is the purpose of this paper to discuss the optical properties of inorganic materials, doped ZnS as a specific system and to point out the chemical considerations that need to he made in the preparation of a phosphor. The latter section of this paper dealswith our experimental procedure concerning the preparatiou of Cu2+-doped ZnS as a phosphor. The excitement that this experiment generates when a student observes phosphoresence under a black light after preparing this compound is truly amazing.Optical Properties of Inorganic Materials The production of light in certain minerals and insects a t normal temperature has fascinated scientists for over four centuries. The first recorded svnthetic luminescent material ~~~~~ ~~ was prepand in 1fiuR hy Casciarolo, n shoemaker from Holoma. lurl\.. who heiited a mixture o i the minrral l~arirp tBaSOJ andcha;coal. The resulting product glowed in the dark aftdr exnosure to sunlieht and was eiven the name ohosohor which . .is derived from thr Greek meaning "light bearer." I.att:r in Ififi!!. a German alchemist liennir Brand discovered a strange -. new element while heating "a secret, magical concoction" in a retort. This element which possessed an "eerie glow" was named phosphorus (this was the white polymorph of phosphorus, P4).In the middle of the 19th century,Stokes showed that the light emission from the mineral fluorite (CaF2) was a phenomenon involving the conversion of shorter wavelength, incident light into longer wavelength radiation (this is Stokes' law). He called the emitted light "fluorescence" and the incident source "exciting light." In addition, Stokes observed that the incident radiation always corresponded to an absorption hand in the material.Fluorescence is exhibited by many naturally occurring minerals such as scheelite (CaWOd, willemite (ZnnSi03, calcite (CaCOd, halo-apatites (Ca5(P04)3X), fluorite (CaF2), and wurtzite (ZnS). Synthetic samples of all these minerals have been shown t...

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Luminescent processes elucidated by simple experiments on ZnS

Cited by 2 publications

References 1 publication

Strahlende Kostbarkeiten: Uran als Farbkörper in Gläsern und Glasuren

Strahlende Kostbarkeiten: Uran als Farbkörper in Gläsern und Glasuren

Preparation of a phosphor, ZnA:Cu2+

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