Wake Forest Physics
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WFU Physics Colloquium
TITLE:
Low-Dimensional Chalcogenide Nanomaterials for
Thermoelectric Composites
SPEAKER:
Chaochao Dun
TIME: Wednesday March 22, 2017 at 2:00 PM
PLACE: Room 101 Olin Physical Laboratory
ABSTRACT
By using hydrothermal reflux methods, a series of chalcogenides
nanostructures were designed. On one hand, ternary metal chalcogenide
nanowires with high thermoelectric figures of merit and power factors
were obtained by using Te1-xSex alloys as templates. On the other
hand, Bi2Se3 , Bi2Te3, Sb2Te3 nanoplates and their derivatives
were also fabricated. After nanostructures were obtained, we further
combine them with polymers such as polyvinylidene fluoride to grantee
their flexibility in thermoelectric devices. Different morphology of the
nanoplates can be well controlled: For example, with different
supersaturation status, different growth mode of Sb2Te3 nanoplates
can be changed from layer by layer to spiral growth with 1 nm in spiral
height. Surface modification and nanoengineering is utilized, like
putting metal ions in the interlayer of n-type Bi2Se3 by taking
advantages of its interlayer gaps, or growing self-assembled metal
nanoparticles (Ag or Cu) on the lateral edges of n-type Bi2Te3 and
p-type Sb2Te3 nanoplates by using their active edges. Unlike in any
previous studies involved in inorganic systems, the Seebeck coefficient
and electrical conductivity can increase in parallel with the introduced
self- assembled heterojunction architectures because of the optimized
electron and phonon transport behavior. This is one of the exciting
achievements we have done in our lab to potentially change
the thermoelectrics field.
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