High-Tg N-triarylamine derivatives as a hole injecting layer in organic light-emitting diodes

Abstract

N-triarylamines, m-MTDAPB and 1-TNAPB, with high glass transition temperature and hole affinity were evaluated as a hole injection layer (HIL) in organic light-emitting diodes (OLEDs) with the configuration of ITO/N-triarylamine/-NPD (HTL)/Alq3 (EML)/LiF/Al. The performance of N-triarylamines as HIL in OLEDs was investigated in terms of turn-on voltage, luminescence, color purity, etc. Better EL performance was observed in OLED with m-MTDAPB as HIL, showing turn-on voltage of 6V and maximum luminescence of 2,976cd/m2 at 13.5V. This might be attributed to well-matched HOMO energy offsets at the interfaces of anode/HIL/HTL layers in OLED with the configuration ofITO/m-MTDAPB/-NPD (HTL)/Alq3 (EML)/LiF/Al, compared to OLED with1-TNAPB as HIL.