The ability to tailor the electronic transmission function in molecular materials with the help of chemical design opens up exciting prospects towards optimising their electronic and thermal transport properties as well as the thermopower. For example, it is now well-established that quantum interference effects, the targeted introduction of substituents or even the exchange of individual atoms in a molecular structure are factors that allow for finetuning of the energetic structure of the junction.[1,2] The notion of a "Molecular" Quantum Technology (MQT) is emerging, here in the context of materials design and especially if favourable thermoelectric properties can be translated from the single-molecule level into "many molecule" devices.<br/>Based on our expertise in Scanning Tunnelling Spectroscopy and advanced data analysis,[3-5] we have recently started to explore different classes of molecules in this context, with particular focus on their electric conductance and thermopower. Employing a variation of distance-dependent I/V spectroscopy in an STM configuration with heated substrate, we have measured the thermopower for simple organic molecules as well as new and more complex molecular designs. Specifically, our values agree well with previously reported values for 1,8-octanedithiol, 4,4'-bipyridine and OPE3. Interestingly, we also find 5-10 times larger values for the thermopower of some new metal-organic compounds, illustrating the potential of molecular systems for significant performance improvement in the future.[6]

Thermopower measurements in single-molecule junctions using multivariate tunnelling current distance spectroscopy

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.