MRS Meetings and Events

 

EL12.02.06 2023 MRS Spring Meeting

Combining Automated Synthesis with Single Molecule Electronics—Understanding the Role of Side Chains on Molecular Charge Transport

When and Where

Apr 11, 2023
4:00pm - 4:15pm

Moscone West, Level 3, Room 3003

Presenter

Co-Author(s)

Jialing Li1,Songsong Li1,Edward Jira1,Nicholas Angello1,Martin Burke1,Charles Schroeder1

University of Illinois at Urbana-Champaign1

Abstract

Jialing Li1,Songsong Li1,Edward Jira1,Nicholas Angello1,Martin Burke1,Charles Schroeder1

University of Illinois at Urbana-Champaign1
The development of next-generation organic electronic materials critically relies on understanding structure-function relationships in conjugated polymers. However, a major challenge lies in accessing the vast chemical space encompassed by synthetic organics while efficiently managing the large synthetic workload to survey new materials. Here, we use automated synthesis to overcome synthetic bottlenecks hindering access to the large chemical space for organic electronics. A library of terphenyl derivatives with different side chain compositions and anchors was prepared using a custom synthesis instrument for automated iterative Suzuki coupling. The role of side chain chemistry on the charge transport properties of conjugated oligomers was then systematically studied using single-molecule charge transport experiments. Our results show an unexpected concentration-dependent bimodal conductance in terphenyl molecular junctions with long alkyl side chains. We found that high conductance states arise due to surface adsorption and backbone planarization induced by the long side chains, which is confirmed by density functional theory simulations and a series of control experiments with asymmetric, planarized, and sterically hindered oligomers. Molecular junctions with oxygen-containing side chains are also investigated, showing high levels of conductance and reduced molecular adsorption behavior compared to alkyl side chains. Overall, our work highlights the role of side chain chemistry on charge transport and opens new avenues in combining automated synthesis with single molecule characterization to develop new materials for organic electronics.

Keywords

chemical synthesis | electrical properties | scanning tunneling microscopy (STM)

Symposium Organizers

Luis Campos, Columbia University
Pascal Gehring, University Catholic Louvain
Maiken Mikkelsen, Duke University
Farnaz Niroui, Massachusetts Institute of Technology

Symposium Support

Bronze
Raith America, Inc.
Royal Society of Chemistry

Publishing Alliance

MRS publishes with Springer Nature