Universal Display Corporation
Organic light emitting device

Abstract:

A region of a device is provided that includes a first material and a second material. The first and second materials may be co-dopants of an emissive material or region. The first material may have an energy gap of not more than about 100 meV between the first excited singlet state and the first excited triplet state. Excitons that transition to the T.sub.1 state can be activated to the S.sub.1 state due to the relatively small energy gap. This thermal activation process is fast enough that non-radiative decay from the T.sub.1 state to the S.sub.0 state is minimal or negligible, thus allowing for sensitization up to and including 100%. The second material may be a phosphorescent-capable material, and may act as a sensitizer to the first material.