Excitation mechanisms in dye-doped organic light-emitting devices

F. Pschenitzka, J. C. Sturm

Research output: Contribution to journalArticlepeer-review

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Abstract

In an organic light-emitting device with a polymeric matrix concurrently doped with two different dyes, the photoluminescence (PL) and electroluminescence (EL) spectra are observed to be very different, with both dyes emitting in PL and only one in EL at room temperature. A simple model based on charge trapping and thermal excitation is introduced to explain this observation. The EL spectral change of a device at 77 K is consistent with this model. In addition, using the same model, the strong dependence of the EL efficiency (but not PL) on the concentration of a single dye in an organic film can be understood. The materials used in this experiment are the polymer poly(9-vinylcarbazole) combined with electron transport molecules, and the dyes coumarin 47, coumarin 6, and Nile red.

Original languageEnglish (US)
Pages (from-to)4354-4356
Number of pages3
JournalApplied Physics Letters
Volume79
Issue number26
DOIs
StatePublished - Dec 24 2001

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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