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1996
Journal Article
Titel
Electro-optic excitation/de-excitation effects in SrS:Ce ACTFEL devices from 15 to 300 K
Abstract
The time-resolved electroluminescence, EL spectrum, UV- and blue-excited photoluminescence, and transferred charge of high-efficiency blue SrS:Ce ac-driven thin-film electroluminescent (ACTFEL) devices were measured over the temperature range of 15-300 K. The purpose of this work was to determine the mechanisms of both optical and electrical excitation/de-excitation in these structures. We found that two thermally activated processes, a strong one around 100 K and a weaker one around 200 K, drastically reduce the Ce3+ luminescent efficiency and limit the overall EL performance. Even though the total transferred charge increases with temperature, these two thermal de-activation processes wipe out any luminescent gains due to increased transferred charge. The fact that a large trailing-edge emission still exists at 15 K indicates that space charge in the form of ionized Ce3+ atoms caused by field-induced delocalization is still present.
Language
English
Tags
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cerium
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electroluminescence
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electroluminescent devices
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phosphors
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photoluminescence
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strontium compounds
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time resolved spectra
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excitation/de-excitation effect
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time-resolved electroluminescence
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blue-excited photoluminescence
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uv-photoluminescence
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transferred charge
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ac thin-film electroluminescent devices
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thermally activated processes
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thermal deactivation processes
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luminescent gains
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trailing-edge emission
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ionized ce3+ atoms
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field-induced delocalization
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15 to 300 k
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100 k
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200 k