Enhanced thermoelectric figure-of-merit in thermally robust, nanostructured superlattices based on SrTiO3
AuthorsAbutaha, Anas I.
Sarath Kumar, S. R.
Dehkordi, Arash Mehdizadeh
Tritt, Terry M.
Alshareef, Husam N.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Imaging and Characterization Core Lab
Functional Nanomaterials and Devices Research Group
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AbstractThermoelectric (TE) metal oxides overcome crucial disadvantages of traditional heavy-metal-alloy-based TE materials, such as toxicity, scarcity, and instability at high temperatures. Here, we report the TE properties of metal oxide superlattices, composed from alternating layers of 5% Pr3+-doped SrTiO3-δ (SPTO) and 20% Nb5+-doped SrTiO3-δ (STNO) fabricated using pulsed laser deposition (PLD). Excellent stability is established for these superlattices by maintaining the crystal structure and reproducing the TE properties after long-time (20 h) annealing at high temperature (∼1000 K). The introduction of oxygen vacancies as well as extrinsic dopants (Pr3+ and Nb5+), with different masses and ionic radii, at different lattice sites in SPTO and STNO layers, respectively, results in a substantial reduction of thermal conductivity via scattering a wider range of phonon spectrum without limiting the electrical transport and thermopower, leading to an enhancement in the figure-of-merit (ZT). The superlattice composed of 20 SPTO/STNO pairs, 8 unit cells of each layer, exhibits a ZT value of 0.46 at 1000 K, which is the highest among SrTiO3-based thermoelectrics. © 2015 American Chemical Society.
SponsorsResearch reported in this publication was supported by King Abdullah University of Science and Technology (KAUST).
PublisherAmerican Chemical Society (ACS)
JournalChemistry of Materials