| abstract |
An OLED device comprises a cathode, an electron- transporting layer (ETL), a light-emitting layer (LEL) containing a fluorescent light-emitting material, a hole-transporting layer (HTL), and an anode, in that order, wherein the ETL comprises a mixture of compounds, including a first compound and at least one second compound, and wherein there is present a hole blocking layer (HBL) adjacent to the LEL on the cathode side. It provides a reduced drive voltage with comparable color hue. |