Electrically Conducting Amorphous Molecular Material: Iodine Doped m-MTDATA as a Hole Injection Buffer Layer in Organic Electroluminescent Devices

Abstract

An electrically conducting amorphous molecular material was prepared by iodine doping of 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA). The use of iodine-doped m-MTDATA, which was identified as m-MTDATA radical cation species with counter anions, as a hole-injection buffer layer in tris(8-quinolinolato)aluminum (Alq₃)-based organic electroluminescent devices led to the reduction of drive voltage and the enhancement of external quantum efficiency as compared with the corresponding device using undoped m-MTDATA. It is indicated that the use of iodine-doped m-MTDATA facilitates not only hole injection from the ITO electrode but also electron injection from the cathode into Alq₃.

Keywords:

• amorphous molecular material
• charge injection
• electrical conductivity
• iodine doping
• m-MTDATA
• organic electroluminescent device