Connectivity-driven bi-thermoelectricity in heteroatom-substituted molecular junctions

Sangtarash, Sara and Sadeghi, Hatef and Lambert, Colin John (2018) Connectivity-driven bi-thermoelectricity in heteroatom-substituted molecular junctions. Physical Chemistry Chemical Physics, 20 (14). pp. 9630-9637. ISSN 1463-9076

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Abstract

To improve the thermoelectric performance of molecular junctions formed by polyaromatic hydrocarbon (PAH) cores, we present a new strategy for enhancing their Seebeck coefficient by utilizing connectivities with destructive quantum interference combined with heteroatom substitution. Starting from the parent PAH, with a vanishing mid-gap Seebeck coefficient, we demonstrate that the corresponding daughter molecule obtained after heteroatom substitution possesses a non-zero, mid-gap Seebeck coefficient. For the first time, we demonstrate a “bi-thermoelectric” property, where for a given heteroatom and parent PAH, the sign of the mid-gap Seebeck coefficient depends on connectivity and therefore the daughter can exhibit both positive and negative Seebeck coefficients. This bi-thermoelectric property is important for the design of tandem thermoelectric devices, where materials with both positive and negative Seebeck coefficients are utilized to boost the thermovoltage. Simple parameter-free rules for predicting the Seebeck coefficient of such molecules are presented, which form a powerful tool for designing efficient molecular thermoelectric devices.

Item Type:
Journal Article
Journal or Publication Title:
Physical Chemistry Chemical Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1600/1606
Subjects:
ID Code:
124431
Deposited By:
Deposited On:
06 Apr 2018 10:38
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Sep 2020 04:12