title: Identification of a positive-Seebeck-coefficient exohedral fullerene.
abstract: If fullerene-based thermoelectricity is to become a viable technology, then fullerenes exhibiting both positive and negative Seebeck coefficients are needed. C60 is known to have a negative Seebeck coefficient and therefore in this paper we address the challenge of identifying a positive-Seebeck-coefficient fullerene. We investigated the thermoelectric properties of single-molecule junctions of the exohedral fullerene C50Cl10 connected to gold electrodes and found that it indeed possesses a positive Seebeck coefficient. Furthermore, in common with C60, the Seebeck coefficient can be increased by placing more than one C50Cl10 in series. For a single C50Cl10, we find S = +8 μV K(-1) and for two C50Cl10's in series we find S = +30 μV K(-1). We also find that the C50Cl10 monomer and dimer have power factors of 0.5 × 10(-5) W m(-1) K(-2) and 6.0 × 10(-5) W m(-1) K(-2) respectively. These results demonstrate that exohedral fullerenes provide a new class of thermoelectric materials with desirable properties, which complement those of all-carbon fullerenes, thereby enabling the boosting of the thermovoltage in all-fullerene tandem structures.
authors.affiliation: Department of physics, Lancaster University, Lancaster LA1 4YB, UK. c.lambert@lancaster.ac.uk qusiyalgaliby@gmail.com and Department of Physics, Northern Border University, Saudi Arabia.
authors.forename: Nasser
authors.initials: N
authors.lastname: Almutlaq
authors.affiliation: Department of physics, Lancaster University, Lancaster LA1 4YB, UK. c.lambert@lancaster.ac.uk qusiyalgaliby@gmail.com and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK and Department of physics, College of Education, Al-Qadisiyah University, Diwaniyah, 58002, IRAQ.
authors.forename: Qusiy
authors.initials: Q
authors.lastname: Al-Galiby
authors.affiliation: Department of physics, Lancaster University, Lancaster LA1 4YB, UK. c.lambert@lancaster.ac.uk qusiyalgaliby@gmail.com and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Bailey
authors.affiliation: Department of physics, Lancaster University, Lancaster LA1 4YB, UK. c.lambert@lancaster.ac.uk qusiyalgaliby@gmail.com and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Lambert