A Strategy to Suppress Phonon Transport in Molecular Junctions Using π-Stacked Systems

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

Qian Li, Mikkel Strange, Ivan Duchemin, Davide Donadio, Gemma C. Solomon

Molecular junctions are promising candidates for thermoelectric devices due to the potential to tune the electronic and thermal transport properties. However, a high figure of merit is hard to achieve, without reducing the phononic contribution to thermal conductance. Here, we propose a strategy to suppress phonon transport in graphene-based molecular junctions preserving high electronic power factor, using nonbonded π-stacked systems. Using first-principles calculations, we find that the thermal conductance of π-stacked systems can be reduced by about 95%, compared with that of a covalently bonded molecular junction. Phonon transmission of π-stacked systems is largely attenuated in the whole frequency range, and the remaining transmission occurs mainly below 5 THz, where out-of-plane channels dominate. The figure of merit (ZT) of the π-stacked molecular junction is dramatically enhanced because of the very low phononic thermal conductance, leaving room for further optimization of the electronic properties. (Figure Presented).

OriginalsprogEngelsk
TidsskriftJournal of Physical Chemistry C
Vol/bind121
Udgave nummer13
Sider (fra-til)7175-7182
Antal sider8
ISSN1932-7447
DOI
StatusUdgivet - 2017

ID: 179405599