Improved efficiency of polymer LEDs using electron transporting layer

Abstract

We report the use of fluorene based copolymers containing quinoline (POF66, P1F66) and pyridine(PFPV) units as electron transporting polymers for multi-layered LEDs. Double-layer device structure combining P1F66 as electron-transporting layer with the emissive MEH-PPV showed a maximum quantum efficiency of 0.03%, which is 30 fold increased compared with ITO/MEHPPV/Al single-layer device. The ETL with the electron deficient moiety improved the LED performance by the characteristics of electron transporting as well as hole blocking between emissive layer and metal cathode.