1 research outputs found
Cellulose Fiber-Based Hierarchical Porous Bismuth Telluride for High-Performance Flexible and Tailorable Thermoelectrics
Porous
modification is a general approach to endowing the rigid inorganic
thermoelectric (TE) materials with considerable flexibility, however,
by which the TE performances are severely sacrificed. Thus, there
remains an ongoing struggle against the trade-off between TE properties
and flexibility. Herein, we develop a novel strategy to combine Bi<sub>2</sub>Te<sub>3</sub> thick film with ubiquitous cellulose fibers
(CFs) via an unbalanced magnetron sputtering technique. Owing to the
nano-micro hierarchical porous structures and the excellent resistance
to crack propagation of the Bi<sub>2</sub>Te<sub>3</sub>/CF architectures,
the obtained sample with a nominal Bi<sub>2</sub>Te<sub>3</sub> deposition
thickness of tens of micrometers exhibits excellent mechanically reliable
flexibility, of which the bending deformation radius could be as small
as a few millimeters. Furthermore, the Bi<sub>2</sub>Te<sub>3</sub>/CF with rational internal resistance and tailorable shapes and dimensions
are successfully fabricated for practical use in TE devices. Enhanced
Seebeck coefficients are observed in the Bi<sub>2</sub>Te<sub>3</sub>/CF as compared to the dense Bi<sub>2</sub>Te<sub>3</sub> films,
and the lattice thermal conductivity is remarkably reduced due to
the strong phonon scattering effect. As a result, the TE figure of
merit, <i>ZT</i>, is achieved as high as ∼0.38 at
473 K, which competes with the best flexible TEs and can be further
improved by optimizing the carrier concentrations. We believe this
developed technique not only opens up a new window to engineer flexible
TE materials for practical applications but also promotes the robust
development of the fields, such as paper-based flexible electronics
and thin-film electronics