Investigation Of The Poly[2-Methoxy-5-(2 '-Ethyl-Hexyloxy)-1,4-Phenylene Vinylene]/Indium Tin Oxide Interface Using Photoemission Spectroscopy

The interface between the luminescent polymer poly [2-methoxy-5-(2(')-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and sputter-cleaned indium tin oxide (ITO) was investigated using photoemission spectroscopy in combination with in situ thin film deposition. MEH-PPV was deposited in high vacuum directly from toluene solution on the ITO substrate using a home-built electrospray thin-film deposition system. The deposition was carried out in multiple steps without breaking the vacuum. In between deposition steps the sample was characterized with x-ray and ultraviolet photoemission spectroscopy. The evaluation of the spectra sequence allowed the determination of the orbital lineup (charge injection barriers) at the interface, as well as the MEH-PPV growth mode at the interface.