Electrophosphorescent organic light emitting diodes

Mark E. Thompson, Sergey Lamansky, Peter Djurovich, Drew Murphy, Feras Abdel-Razzaq, Stephen R. Forrest, Marc Baldo, Paul E. Burrows, Chihaya Adachi, Theodore X. Zhou, Lech Michalski, Kamala Rajan, Julie J. Brown

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)

Abstract

We have fabricated saturated red, orange, yellow and green OLEDs, utilizing phosphorescent dopants. Using phosphorescence based emitters we have eliminated the inherent 25% upper limit on emission observed for traditional fluorescence based systems. The quantum efficiencies of these devices are quite good, with measured external efficiencies > 15% and > 40 lum/W (green) in the best devices. The phosphorescent dopants in these devices are heavy metal containing molecules (i.e. Pt, and Ir), prepared as both metalloporphyrins and organometallic complexes. The high level of spin orbit coupling in these metal complexes gives efficient emission from triplet states. In addition to emission from the heavy metal dopant, it is possible to transfer the exciton energy to a fluorescent dye, by Förster energy transfer. The heavy metal dopant in this case acts as a sensitizer, utilizing both singlet and triplet excitons to efficiently pump a fluorescent dye. We discuss the important parameters in designing electrophosphorescent OLEDs as well as their strengths and limitations. Accelerated aging studies, on packaged devices, have shown that phosphorescence based OLEDs can have very long device lifetimes.

Original languageEnglish
Pages (from-to)337-340
Number of pages4
JournalSID Conference Record of the International Display Research Conference
Publication statusPublished - 2000
Externally publishedYes
Event20th International Display Research Conference - Palm Beach, FL, United States
Duration: Sep 25 2000Sep 28 2000

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

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