Microstructural control suppresses thermal activation of electron transport at room temperature in polymer transistors

Alessandro Luzio, Fritz Nübling, Jaime Martin, Daniele Fazzi, Philipp Selter, Eliot Gann, Christopher R. McNeill, Martin Brinkmann, Michael Ryan Hansen, Natalie Stingelin, Michael Sommer, Mario Caironi

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)

Abstract

Recent demonstrations of inverted thermal activation of charge mobility in polymer field-effect transistors have excited the interest in transport regimes not limited by thermal barriers. However, rationalization of the limiting factors to access such regimes is still lacking. An improved understanding in this area is critical for development of new materials, establishing processing guidelines, and broadening of the range of applications. Here we show that precise processing of a diketopyrrolopyrrole-tetrafluorobenzene-based electron transporting copolymer results in single crystal-like and voltage-independent mobility with vanishing activation energy above 280 K. Key factors are uniaxial chain alignment and thermal annealing at temperatures within the melting endotherm of films. Experimental and computational evidences converge toward a picture of electrons being delocalized within crystalline domains of increased size. Residual energy barriers introduced by disordered regions are bypassed in the direction of molecular alignment by a more efficient interconnection of the ordered domains following the annealing process.

Original languageEnglish
Article number3365
Number of pages13
JournalNature Communications
Volume10
Issue number1
DOIs
Publication statusPublished - 29 Jul 2019

Cite this