On the manifestation of electron-electron interactions in the thermoelectric response of semicrystalline conjugated polymers with low energetic disorder

M. Statz, D. Venkateshvaran, X. Jiao, S. Schott, C. R. McNeill, D. Emin, H. Sirringhaus, R. Di Pietro

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Abstract

The development of semicrystalline polymer semiconductors with field-effect mobilities comparable to or even exceeding those of amorphous silicon has exposed limitations of describing charge transport in these materials with disorder-based models developed originally for more disordered, lower mobility polymers. Here, we show that the charge carrier density and temperature dependence of the field-effect electron mobility and Seebeck coefficient in the semicrystalline polymer P(NDI2OD-T2) with varying degrees of crystallinity are incompatible with a description of charge transport being limited by energetic disorder effects. We provide instead direct evidence of low disorder, narrow band conduction. A spatially inhomogeneous density of states and the inclusion of short range electron–electron interactions allow to consistently explain both the measured mobility and Seebeck coefficient. These results provide a rationale for improving thermoelectric efficiency of polymer semiconductors via increasing the extension of the crystalline domains.

Original languageEnglish
Article number16
Number of pages10
JournalCommunications Physics
Volume1
DOIs
Publication statusPublished - 1 Dec 2018

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