Ca3Co4O9+δ and Ca3-x Dyx Co3.95Ga0.05O9+δ (x = 0.05, 0.10) samples were prepared by conventional solid-state synthesis, and their thermoelectric properties measured at 25 K to 300 K. The x-ray diffraction patterns revealed that all the samples are single phase. The thermopower of all the samples was positive, indicating that the predominant carriers are holes over the entire temperature range. The highest power factor among all the samples (2.45 μW cm-1 K-2 at 132 K) was obtained for Ca2.9Dy0.1Co3.95Ga0.05O 9+δ, being about 80% higher than that of the undoped sample. Ca2.9Dy0.1Co3.95 Ga0.05O 9+δ had the highest dimensionless figure of merit of 0.033 at 300 K, representing an improvement of about 74% compared with undoped Ca 3Co4O9+δ .
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry