Thermoelectric conversion via laser-induced voltage in highly textured polycrystalline Na{sub x}CoO{sub 2} ceramic

Journal Article · Mon Nov 14 23:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3660781· OSTI ID:22036770

Yan, G W; Wang, Y; Zhang, H ^[1]; Yu, L; Zhang, P X ^[1]; Habermeier, H -U ^[2]

---

1. Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)
2. Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart D-70569 (Germany)

We have studied and analyzed the laser-induced voltage effect in highly c-axis-oriented polycrystalline Na{sub x}CoO{sub 2}. The textured and layered stacking Na{sub x}CoO{sub 2} (x {approx} 0.7) bulks were prepared by a solid-state reaction process. Under the irradiation on Na{sub 0.67}CoO{sub 2} bulk surface with pulsed laser ({lambda} = 248 nm), the induced voltage signals were observed on the inclined surface with rise time 30 ns-43 ns and peak voltage 200 mV-500 mV; the voltage peak values show a linear dependence of laser energy densities. The crystal grains orientation plays a critical role in voltage peak value whether in film or texture bulk. The transverse voltage signal brings the information of thermoelectric anisotropy. In Na{sub x}CoO{sub 2} band structure, the Fermi surface is different in the ab plane and along the c axis, leading to anisotropy of Seebeck coefficient. Additionally, the artificial structure of the inclined surface for highly textured bulk enables us to obtain a transverse voltage on inclined surface. These results demonstrated the layered textured bulk has potential applications in waste-heat conversion via transverse thermoelectric effect.

• OSTI ID: 22036770
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 10 Vol. 110; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
CERAMICS
COBALT OXIDES
ELECTRIC POTENTIAL
ELECTRONIC STRUCTURE
FERMI LEVEL
FILMS
GRAIN ORIENTATION
IRRADIATION
LASER RADIATION
POLYCRYSTALS
SEEBECK EFFECT
SODIUM COMPOUNDS
SOLIDS
SURFACES
TEXTURE
THERMOELECTRIC CONVERSION