Tuning the polarity of charge carriers using electron deficient thiophenes

Authors

Jonathan Z. Low, Columbia University
Brian Capozzi, Columbia University
Jing Cui, Columbia University
Sujun Wei, CUNY Queensborough Community CollegeFollow
Latha Venkataraman, Columbia University
Luis M. Campos, Columbia University

Document Type

Article

Publication Date

2-28-2017

Abstract

Thiophene-1,1-dioxide (TDO) oligomers have fascinating electronic properties. We previously used thermopower measurements to show that a change in charge carrier from hole to electron occurs with increasing length of TDO oligomers when single-molecule junctions are formed between gold electrodes. In this article, we show for the first time that the dominant conducting orbitals for thiophene/ TDO oligomers of fixed length can be tuned by altering the strength of the electron acceptors incorporated into the backbone. We use the scanning tunneling microscope break-junction (STM-BJ) technique and apply a recently developed method to determine the dominant transport channel in single-molecule junctions formed with these systems. Through these measurements, we find that increasing the electron affinity of thiophene derivatives, within a family of pentamers, changes the polarity of the charge carriers systematically from holes to electrons, with some systems even showing mid-gap transport characteristics.

Comments

This article was originally published in Chemical Science, available at DOI: 10.1039/c6sc05283e.

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.