Nickel-Fullerene Nanocomposites as Thermoelectric Materials

Andriy Nadtochiy¹, Viktor Kozachenko¹, Oleg Korotchenkov¹, Viktor Schlosser²

1 Department of Physics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine.

2 Department of Electronic Properties of Materials, Faculty of Physics, University of Vienna, A-1090 Wien, Austria.

DOI: 10.3390/nano12071163

ABSTRACT: Nickel films with nanovoids filled with fullerene molecules have been fabricated. The thermoelectric properties of the nanocomposites have been measured from room temperature down to about 30 K. The main idea is that the phonon scattering can be enhanced at the C₆₀/matrix heterointerface. The distribution of atoms within the Ni and Ni-C₆₀ layers has been characterized by Auger depth profiling. The morphology of the grown samples has been checked using cross-sectional scanning electron microscopy (SEM). The Seebeck coefficient and electrical conductivity have been addressed employing an automatic home-built measuring system. It has been found that nanostructuring using Ar⁺ ion treatment increases the thermopower magnitude over the entire temperature range. Incorporating C₆₀ into the resulting voids further increased the thermopower magnitude below ~200 K. A maximum increase in the Seebeck coefficient has been measured up to four times in different fabricated samples. This effect is attributed to enhanced scattering of charge carriers and phonons at the Ni/C₆₀ boundary.

Keywords Seebeck coefficient; fullerene; metal; nanocomposite.