Electronic structure of interfaces between copper-hexadecafluoro- phthalocyanine and 2,5-bis(4-biphenylyl) bithiophene

Abstract

The interfaces formed between copper-hexadecafluoro-phthalocyanine (F16 CuPc) and 2,5-bis(4-biphenylyl) bithiophene (BP2T) were examined using photoemission and inverse photoemission spectroscopy. It is observed that in F16 CuPcBP2T the heterojunction is characterized by band bending in both materials, while in BP2T F16 CuPc the band bending is confined in BP2T only. The combination of the band bending and finite Debye lengths provides an explanation to the observed ambipolar behavior of the organic thin film transistors based on such heterojunctions. © 2007 American Institute of Physics.