Growth of phenylene vinylene thin films via surface polymerization by ion-assisted deposition

Abstract

Surface polymerization by ion-assisted deposition was used to grow phenylene vinylene films (SPIAD-PPV) using the evaporation of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-bis((4',4"-bisstyryl) benzene) (MEH-OPV5) and the simultaneous deposition of non-mass-selected 10–200 eV thiophene or acetylene ions. Images recorded by scanning electron microscopy showed differences in SPIAD-PPV film morphology versus evaporated MEH-OPV5 that indicated changes in the underlying chemical structure. Spectroscopic differences between MEH-OPV5 and SPIAD-PPV films suggested preferential attack of vinylene groups and/or hydrocarbon side chains. A possible explanation for the changes in morphology and electronic structure was cross-linking at vinylene sites of adjacent MEH-OPV5 molecules which could lead to changes in molecular packing. Although morphological and electronic differences were seen for SPIAD-PPV films, these films still showed valence bands characteristic of phenylene vinylenes.