Energy level alignment of a hole-transport organic layer and ITO: Towards applications for organic electronic devices

Abstract : 2,2’,6,6’-tetraphenyl-4,4’-dipyranylidene (DIPO-Ph4) was grown by vacuum-deposition on an indium tin oxide (ITO) substrate. The films were characterized by atomic force microscopy and synchrotron radiation UV and X-ray photoelectron spectroscopy to gain an insight into the material growth and to better understand the electronic properties of the DIPO-Ph4/ITO interface. Results show formation of cationic DIPO-Ph4 at ITO interface with a charge transfer from the organic layer to the anode material. This has been confronted to DFT calculations. We present as a conclusion the energetic diagram of the DIPO-Ph4/ITO system and some perspectives with a typical photovoltaic active layer: P3HT:PCBM.