Low temperature synthesis thermoelectric properties of BiCuSeO and Ni-doped BiCuSeO
賴融廷1*, 劉嘉吉1
1Department of Physics, National Changhua University of Education, Changhua, Taiwan
* presenting author:Rung-Ting Lai, email:qazwsx410359@gmail.com
Thermoelectric materials are environmentally friendly energy materials. They can be used to harvest waste heat for generating electricity. The thermoelectric performance of a given material is evaluated by the dimensionless figure of merit, zT, where z= (S2σ)/κ and S, σ, T are the thermopower, electrical conductivity, thermal conductivity, and absolute temperature, respectively. The greater the zT value is, the better the thermoelectric performance is.
BiCuSeO exhibits large thermopower (~450 μV/K at 700 K) and low thermal conductivity (~0.4W/m-K at 700 K), nevertheless shows low electrical conductivity (~15 S/cm at 700 K). Our research aims to increase the electrical conductivity of BiCuSeO. Most of the research work of fabricating BiCuSeO adopt high-temperature solid state reaction. In this work, we fabricate BiCuSeO and Ni-doped BiCuSeO using sol-gel synthesis followed by hot pressing. The electron transport measurements indicate that the power factor (S2σ) of BiCuSeO is significantly enhanced (1.45μW/cm-K2 at 700 K) as compared to that fabricated using solid state reaction (0.75 μW/cm-K2 at 700K). The enhancement of the power factor arises from the much increase carrier concentration in our material. In addition, the Ni-doped power factor is 3μW/cm-K2 at 700K. These results indicate that our fabrication procedure and Ni-doping can improve the power factor of BiCuSeO.

Keywords: thermoelectrics, Ni-doped, Low temperature synthesis