Abstract

We investigate the electrical properties of three different trilayer organic light-emitting diodes (OLEDs), one of which is based on a conventional layered structure and the others on a blended structure where an emitting layer (EML) is uniformly or stepwise mixed with an electron transport layer (ETL), Tris-(8-hydroxyquinoline) aluminum ( ${\rm Alq}_{3}$ ). By way of simulations, we visualize the electrical behaviors that provide a clear understanding on why the uniformly mixed structure enhances further the longevity of OLEDs, compared to the other configurations. Namely, the uniformly mixed structure has the lowest concentration of positive charges in the ETL (thereby reducing oxidative degradation of ${\rm Alq}_{3}$ ) and weakest electric field (decreasing the probability of Joule heating), followed by the stepwise mixed one and then the layered one. However, such blended structures show lower recombination efficiency due to the delocalization of carriers (recombination), which has been demonstrated by simulations of the current balance.

© 2009 IEEE

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription