An effective cathode structure for inverted top-emitting organic light-emitting devices

Inverted top-emitting organic light-emitting devices (OLEDs) combine technical merits of top-emitting OLEDs and inverted OLEDs for active-matrix OLED displays. One major challenge in inverted top-emitting OLEDs, however, is to prepare a reflective bottom cathode capable of effective electron injection. In this letter, we report an effective cathode structure for enhancing the electron-injection capability of the bottom cathode in inverted top-emitting OLEDs. Such an approach does not involve handling reactive metals during fabrication and permits use of highly reflective materials such as Al and Ag as the bottom cathodes. Efficient inverted top-emitting devices employing such a cathode scheme have been demonstrated.