Abstract:
Thermoelectric (TE), is a solid-state technology to convert waste heat into useful energy
based on Seebeck effect, which can make significant contributions to solve the global
energy crisis by providing a sustainable energy solution. SnSe, being a lead-free,
environmentally friendly and cheap semiconductor, has been an attractive choice for TE
community. Here, the focus is on its layered structure of the same chalcogenide family,
SnSe2, an n-type semiconductor. In this research, we analyzed the potential of SnSe2-rGO
composite as a TE material and the effect of rGO concentration on its TE properties.
SnSe2-rGO composites were synthesized via solvothermal route followed by sintering at
550°C in the presence of Argon. In-situ doping of rGO within SnSe2 matrix was
successfully achieved. The resultant composite showed a significant improvement in
electrical conductivity which displayed a peak value of 2479 S/m (Pure SnSe2=750 S/m)
at 300K. This enhancement is due to the electronic structure of SnSe2 and the presence of
rGO conductive sheets, which improved the carrier concentration. Introduction of rGO
also resulted in controlling the lattice thermal conductivity due to phonon scattering. The
investigation showed that increasing the rGO concentration had a positive impact on the
overall ZT of the samples, achieving a peak ZT of 0.18 for 4-SG sample at 750K. This
increase can be related to the increasing electrical conductivity due to rGO addition and
the reduction in band gap.
