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

Abstract

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 (approximately 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.

Cross‐Linked Multifunctional Conjugated Polymers Prepared by In Situ Electrochemical Deposition for a Highly‐Efficient Blue‐Emitting and Electron‐Transport Layer

“…The PFCzPO ED film has a RMS roughness of 3.64 nm, which is analogous to the film morphology obtained after spin‐coating from solution. The morphology of ED films is greatly improved compared to previously reported polymer ED films 8–12. We point out that this is the first ED film using a CP precursor that exhibits such a smooth morphology.…”

“…There are only a few reports about ED that use CPs as precursors 8–12. However, resultant ED films showed a very rough morphology and weak fluorescence, which makes it difficult to use them for the application in devices.…”

“…One important factor to obtain a high‐quality ED film is ED under low potential, which benefits the doping/dedoping process. The previous reported ED of CPs precursors usually required a high oxidation potential applied during the ED process because the CPs precursors with low solubility showed low electroactivity 8–12. But ED under a very high oxidation potential will lead to more structural defects and high electrolyte doping level, which will obviously affect the optoelectronic functions, especially the luminescent properties of ED films.…”