A morphology study on thermoelectric Al-substituted ZnO

Abstract

Al-substituted ZnO is a potential high temperature n-type thermoelectric material. The thermoelectric properties, the morphology and the microstructure of Zn 0.98 Al 0.02 O prepared by soft chemistry synthesis were studied and compared with samples synthesised by solid state reaction. The soft chemistry method produces samples with better connectivity of the grains and less structural defects leading to a lower electrical resistivity and a higher thermal conductivity than solid state reaction. The Seebeck coefficient is not affected by the microstructure of the material. The highest value of the dimensionless Figure of Merit ZT of 0.21 is therefore reached at 1275 K for the samples from soft chemistry synthesis.

In2O3-Based Thermoelectric Materials: The State of the Art and the Role of Surface State in the Improvement of the Efficiency of Thermoelectric Conversion

“…Wu et al [127] have found that the presence of polyparaphenylene (PPP) nanoparticles in the Zn 0.95 Ni 0.05 O matrix was also effective in improving the ZT up to~0.54 at 1173 K. This improvement was achieved due to an increased power factor and a reduction in thermal conductivity. However, the values of k for these nanocomposites did not drop below 2 W/m·K even at 1000 K. For most other studies, the ZT did not exceed 0.15-0.3 [130,131].…”