Spectroscopic Characterization of Metal–Polymer Interface for Electronic Applications

Abstract

The interfacial crystallinity of polymer semiconductors is critical toward fabricating the high-performance organic electronic devices like organic field-effect transistors wherein the majority of charge injection and collection occurs near the narrow metal–polymer interface. The two popular configurations of solution-processed organic transistors, viz., top contact and bottom contact involve metal–polymer interfaces with opposite sequence of deposition of metal electrode and polymer semiconductor. In this article, the crystallinity degradations of polymer films near the interfaces with electrodes in the two configurations have been described using some conventional spectroscopy techniques such as absorption, photoluminescence, and Raman spectroscopy techniques. It is observed and validated that crystallinity of solution-processed polymer film becomes severely degraded when metal electrode is coated over polymer film (top contact), in comparison to when polymer is coated over metal electrode (bottom contact) leading to the formation carrier injection barrier near the interface.