초록 |
A highly efficient and soluble red emitting cyclometalated heteroleptic iridium (III) complex (Th-PQ)2Ir(4-OXD-pic) was designed and successfully synthesized for solution process phosphorescence organic light-emitting diodes (PhOLEDs). The incorporation of the electron transport material (ETM) in ancillary ligand can enhance the efficiencies of the device. The photophysical, thermal and electrochemical properties of the material were systematically investigated by UV-visible, TGA, DSC and cyclic voltammetry. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of (Th-PQ)2Ir(4-OXD-pic) were 2.9 and 5.1 eV, respectively. The red PhOLEDs were fabricated with the configuration of ITO/PEDOT:PSS/TCTA:TPBI:Dopant/TPBI/LiF/Al. The optimized OLEDs showed better performance than without ETM such as maximum luminance efficiency of 10.7 cd/A, maximum power efficiency of 3.4 lm/W and maximum external quantum efficiency of 12.2 % at 8.2 V driving voltage. |