Novel Starburst Molecule as a Hole Injecting and Transporting Material for Organic Light-Emitting Devices

We report the synthesis of a novel starburst molecule, 4,4‘,4‘ ‘-tris( N -3-methylphenyl- N -(9-ethylcarbazyl-3)amino) triphenylamine (PCATA), and its application in organic light-emitting devices (OLEDs). The introduction of PCATA into the standard NPB/Alq 3 OLED as the hole injecting and transporting layer dramatically enhanced the device efficiency to 5.7 cd/A and 2.2 lm/W, which are a factor of 2 higher than those of the standard OLED without the PCATA layer. The performance enhancement is attributed to a better balance of hole and electron injection in the PCATA-added OLED.