TY - JOUR
T1 - Electrophosphorescent organic light emitting diodes
AU - Thompson, Mark E.
AU - Lamansky, Sergey
AU - Djurovich, Peter
AU - Murphy, Drew
AU - Abdel-Razzaq, Feras
AU - Forrest, Stephen R.
AU - Baldo, Marc
AU - Burrows, Paul E.
AU - Adachi, Chihaya
AU - Zhou, Theodore X.
AU - Michalski, Lech
AU - Rajan, Kamala
AU - Brown, Julie J.
PY - 2000
Y1 - 2000
N2 - 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.
AB - 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.
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M3 - Conference article
AN - SCOPUS:0034589357
SP - 337
EP - 340
JO - SID Conference Record of the International Display Research Conference
JF - SID Conference Record of the International Display Research Conference
SN - 1083-1312
T2 - 20th International Display Research Conference
Y2 - 25 September 2000 through 28 September 2000
ER -