Design of Band Engineered and Nanostructure Engineered Metal
Chalcogenide Thermoelectrics
Zhi-Gang Chen1*, and Jin Zou1,2*
1Materials
2Centre
Engineering, The University of Queensland, Brisbane QLD 4072, Australia
for Microscopy and Microanalysis, The University of Queensland, Brisbane QLD 4072,
Australia
*Corresponding author: Email z.chen1@uq.edu.au; j.zou@uq.edu.au,
To reduce our dependence on fuel oil and green gas emission, the search for the
high figure of merit (ZT) thermoelectric materials have been carried out extensively to
convert waste heat into useful electricity [1]. Metal chalcogenide semiconductors with
low bandgaps, such as Bi2Te3 (0.13 eV), Bi2Se3 (0.3 eV), In4Se3 (0.50 eV), have been
considered as best candidates for room or medium temperature thermoelectrics [2, 3].
Therefore, development of metal chalcogenide semiconductors has been a globally
focused topic in the Materials Science. However, their bulk forms have reached their
theoretical thermoelectric performance limit due to their nature of high bulk thermal
conductivity. However, achieving high ZT thermoelectric materials has been a
challenging task because it requires a combination of low thermal conductivity κ and
high power factor α2σ, that is, high electrical conductivity σ and Seebeck coefficient α,
although these properties often follow unfavorably opposing trends [4]. To attack the
problem, this study focuses on the design of nanostructuring metal chalcogenides to
manipulate their electronic structures and phonon properties through a band
engineering methodology.
Here, we developed green and facile solvothermal methods to fabricate different
metal chalcogenide nanomaterials (such as Bi2Te3, Bi2Se3, or Sb2Te3 nanoplates or
nanowires, In3Se4 nanoparticles) and their impurity-doped metal chalcogenide
nanomaterials with different dopants (e.g. Na [5], Mn [6], Fe, and Cu). To enhance
the surface areas of Bi2Te3 nanostructures and manipulate the carrier density, a
novel hollow Bi2Te3 nanoplates, which also show a super-low thermal conductivity of
0.35 Wm-1K-1 and an improved high ZT of 1.5 at 300K. In an attempt of doping Na
into Bi2Te3 nanosheets, outstanding surface conductance was demonstrated in the
synthesized Na doped Bi2Te3 nanosheets [5]. A high-performing Bi2Te3-Te
heterostructures with a ZT of 0.74 at 300K through nanostructuring has been
developed [7]. Moreover, paramagnetic Cu-doped Bi2Te3 nanosheets [8] and high
Curie Temperature Bi2Te3 nanosheets [6] have also been developed and improved
thermoelectric performance are also observed.
Acknowledgement This work was supported by the Australian Research Council.
ZGC would thank the QLD government for a smart state future fellowship
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