Assembly, structure and thermoelectric properties of 1,1’-dialkynylferrocene ‘hinges’

Luke Alexander Wilkinson, Troy L R Bennett, Iain M Grace, Joseph Hamill, Xintai Wang, Sophie Au-Yong, Ali Ismael, Samuel Jarvis, Songjun Hou, Tim Albrecht, Lesley F Cohen, Colin Lambert, Benjamin J Robinson, Nicholas Long

Research output: Contribution to journalArticlepeer-review

Abstract

Dialkynylferrocenes exhibit attractive electronic and rotational features that make them ideal candidates for use in molecular electronic applications. However previous works have primarily focussed on single-molecule studies, with limited opportunities to translate these features into devices. In this report, we utilise a variety of techniques to examine both the geometric and electronic structure of a range of 1,1’-dialkynylferrocene molecules, as either single-molecules, or as self-assembled monolayers. Previous single molecule studies have shown that similar molecules can adopt an ‘open’ conformation. However, in this work, DFT calculations, STM-BJ experiments and AFM imaging reveal that these molecules prefer to occupy a ‘hairpin’ conformation, where both alkynes point towards the metal surface. Interestingly we find that only one of the terminal anchor groups binds to the surface, though both the presence, and nature of the second alkyne affects the thermoelectric properties of these systems. First, the secondary alkyne acts to affect the position of the frontier molecular orbitals, leading to increases in Seebeck coefficient. Secondly, theoretical calculations suggested that rotating the secondary alkyne away from the surface acts to modulate thermoelectric properties. This work represents the first of its kind to examine the assembly of dialkynylferrocenes, providing valuable information about both their structure and electronic properties, as well as unveiling new ways in which both of these properties can be controlled.
Original languageEnglish
JournalChemical Science
Early online date27 Jul 2022
DOIs
Publication statusE-pub ahead of print - 27 Jul 2022

Cite this