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Electro-optic excitation/de-excitation effects in SrS:Ce ACTFEL devices from 15 to 300 K


Journal of the Society for Information Display 4 (1996), No.4, pp.287-291
ISSN: 1071-0922
International Conference on the Science and Technology of Display Phosphors <1, 1995, San Diego/Calif.>
Conference Paper, Journal Article
Fraunhofer HHI ()
cerium; electroluminescence; electroluminescent devices; phosphors; photoluminescence; strontium compounds; time resolved spectra; excitation/de-excitation effect; srs:ce actfel devices; time-resolved electroluminescence; blue-excited photoluminescence; uv-photoluminescence; transferred charge; ac thin-film electroluminescent devices; thermally activated processes; thermal deactivation processes; luminescent gains; trailing-edge emission; ionized ce3+ atoms; field-induced delocalization; 15 to 300 k; 100 k; 200 k; srs:ce

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.