FTIR spectroscopic analysis and STM studies of electroluminescent Eu(DBM)3 bath thin films vacuum deposited onto Au surface

Molecular organization and morphology of vacuum deposited (VD) thin films of the europium complex of europium(dibenzoylmethanato)3(bathophenanthroline) (Eu(DBM)3 bath) from metal-organic planar light-emitting nanocomposites consisting of gold island films and VD Eu(DBM)3 bath film were investigated by FTIR spectroscopy and scanning tunneling microscopy (STM). It has been found that thermal evaporation in vacuum does not cause chemical decomposition of Eu(DBM)3 bath, and that the obtained films are essentially amorphous. Reflection–absorption IR spectra show no predominant orientation of Eu(DBM)3 bath molecules in the films with respect to the substrate. With the STM method, the morphology and structure of the near-surface layers of Eu(DBM)3 bath films were characterized, and it was found that they consist of self-assembled molecular dimers closely packed along the Au [110] steps on the Au(111) terrace. With increase of the Eu(DBM)3 bath film thickness, the ordered structure is lost.