Morphological Control of the Electrochemically Deposited Poly(4-vinyltriphenylamines) (PVTPAs)

The morphology of the thin films obtained from electrochemical deposition of poly(4-vinyltriphenylamine)s (PVTPAs) on ITO surface varies as their molecular weight increases. The SEM studies revealed that while uniform coating could be obtained from low molecular weight PVTPAs (∼2700), uneven and rough coating with numerous cracks on the surface would be formed from high molecular weight PVTPAs. These defects could be reduced by using our surface modification strategy, in which the ITO surface was first primed with a thin layer of electrochemical coating of poly(methylenetriphenylamine) (PMTPA). This coating would turn the highly polar ITO surface into a nonpolar conducting surface that benefits for the PVTPA deposition. Our electroluminescence test suggested that this type of PMTPA/PVTPA composite film is good for hole injection and transportation.