Interpretation of the Electrical Properties of π-Conjugated Polymer Based on Near-Edge X-ray Absorption Fine Structure Spectroscopy

초록

We systematically study the ordering- and conjugating-dependent electrical properties of semiconducting polymers in OFET, using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, as well as other structural analyses. Various semiconducting polymers, such as diketopyrrolopyrrole (DPP)-based donor-acceptor copolymers, are selectively treated to enhance the ordering and conjugating structures in the cast films. Since the electrical properties of semiconducting polymers are significantly affected by the extension and orientation of the semiconducting domains containing the π-π overlapped chains, specifically, NEXAFS spectroscopy is the one of the most powerful tools to monitor the information related to the interfacial orientation and alignment of the conjugated polymers with respect to substrate surfaces. Here, the basic principle of NEXAFS spectroscopy and how to interpret the NEXAFS spectra acquired from various semiconducting polymer films are introduced.