Combined SPM investigation on the interfacial structure of a phthalocyanine/conjugated polymer composite film

The morphology of the composite film of organic semiconductors determines the properties and performances of devices to a large extent. In this work, we present a combined AFM and STM study on the interfacial structures of CuPcOC8 and CuPcOC8/PmPV composite films on graphite surface. For CuPcOC8 thin films, the face-on epitaxial growth of CuPcOC8 could persist within 3 to 5 monolayers and the formation of π-π stacked columns will occur with edge-on configuration when the film thickness further increases. For the CuPcOC8/PmPV composite film with 1:1 weight ratio, STM results reveal a preferential adsorption of PmPV on graphite surface, while AFM results indicate the phase segregation in the upper layer. STM also reveals in the molecular scale good compatibility of CuPcOC8 with PmPV.