High-Efficiency Solution-Processed Small Molecule Electrophosphorescent Organic Light-Emitting Diodes

Spin-coated small-molecule organic light-emitting diodes (OLEDs) based on green-emitting Ir(mppy)(3)-doped 4,4'-bis(9-carbazolyl)-biphenyl (CBP) blended with electron- and hole-transporting molecules are demonstrated to have very high efficiencies (up to 60 Im/W and 69 Cd/A without any outcoupling enhancement, which can double with a high-quality microlens array). An additional electron-transporting/hole-blocking BPhen layer is thermally evaporated on the active layer, followed by the LiF/Al cathode.