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New Chemical Reaction Process of a Bi2Te2.7Se0.3 Nanomaterial for Feasible Optimization in Transport Properties Resulting in Predominant n‑Type Thermoelectric Performance
journal contribution
posted on 2016-04-28, 00:00 authored by Cham Kim, Chang
Eun Kim, Ju Young Baek, Dong Hwan Kim, Jong Tae Kim, Ji Hyeon Ahn, David
Humberto Lopez, Taewook Kim, Hoyoung KimVarious
chemical reaction processes have been adopted to synthesize
Bi2Te3 thermoelectric nanomaterials for achieving
remarkably low thermal conductivities, but chemical contaminations
were usually pointed out as flaws, severely deteriorating electrical
conductivities. We devised a novel water-based chemical reaction process
for a Bi2Te2.7Se0.3 nanocompound
in which the possibility for chemical contaminations was reduced.
We successfully synthesized a small and highly distributed Bi2Te2.7Se0.3 nanocompound with high purity
and adequately packed it via a spark plasma sintering process to produce
a nanobulk structure. The resulting nanobulk specimen exhibited a
physical density as high as the theoretical one with highly distributed
nanograins; thus, we were able to obtain remarkably high electrical
conductivity while maintaining thermal conductivity as low as possible.
The synergistic effect was greatly induced between the transport properties;
thus, the highest reported figure of merit value was achieved for
n-type Bi2Te3 in the bulk phase.