Electrical and Thermal Transport Property Studies of High-Temperature Thermoelectric Materials.
Interim technical rept. 15 May 84-15 May 85,
BATTELLE PACIFIC NORTHWEST LAB RICHLAND WA
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The research effort during this reporting period has continued to emphasize the study of electronically conducting oxides, which was initiated in the previous reporting period. The high-temperature transport property data base has been expanded by continued measurements in several systems under study, and a theoretical model for thermoelectric properties based on a small polaron transport has been developed. The study of the transport properties of the In2O3-SnO2 system, which was initiated during the previous reporting period, has been completed. Low values for the figure of merit were obtained, as expected, for these degenerate-type semiconductors. Some high-temperature materials that exhibit high figures of merit. The theoretical model developed under this program predicts that narrow-band semiconductors with small polaron hopping along inequivalent sites of distorted sublattices can result in increases in both electrical conductivity and Seebeck coefficient with temperature without significant increases in thermal conductivity. High figures of merit, greater than 1.0 at 1000 K, that increases with temperature are predicted by the model. The model is being applied to the divalent metal-doped Y, LaCrO3 systems with the ABO3 perovskite structure. Transport property data obtained during this reporting period for different divalent metal dopants at different concentrations are being used to evaluate the model.
- Electricity and Magnetism
- Solid State Physics