Microstructure And Themoelectric Properties Of LaCuSeO Based Oxide

As we are facing to the energy crisis and the environment problem,Thermoelectric material which is a green and environment–friendly has receivedmuch attention from researchers all over the world. LaCuSeO, a layered oxyselenide,is a candidate thermoelectric material in high temperature ranges due to its lowinstinct thermal conductivity and high temperature stability. However, theconductivity of LaCuSeO is also low, result in a low ZT value which limits thepractical applications. doping is an effective approach to enhance thermoelectricperformance as it can increase carriers concentration and increase the conductivityof LaCuSeO. In this dissertation, Ba doping and Pb doping LaCuSeO oxyselenideshas been prepared using a solid state reaction followed by hot pressing sintering.The phase structure of the powder is analyzed by XRD. the microtopography isanalyzed by SEM.The effect of Ba or Pb to the thermoelectric property of LaCuSeOis analyzed by texting the thermoelectric property of these materials.Phase structure and thermoelectric property of Ba doped La1-xBaxCuSeO havebeen investigated. Researches have shown that La1-xBaxCuSeO（0≤x≤0.15）are purephase. Ba doping is an effective approach to enhance conductivity as it can increasecarriers concentration of LaCuSeO. Extra point defect can be introduced after Badoping, which leads to the decrease of the phonon thermal conductivity and thermalconductivity. ZT at600℃is increased from0.16for LaCuSeO to0.33forLa0.9Ba0.1CuSeO. The increase of ZT is105%.Studies have found that La1-xPbxCuSeO（0.025≤x≤0.15）consist of LaCuSeOphase and PbSe phase.The lattice constant of c axis is decreased by Pb doping. Pbdoping can enhance conductivity and decrease the Seebeck coefficient, which leadto little change of the power factor. At low temperature range, thermal conductivityis slightly reduced by Pb doping. Pb doping has no effect to thermal conductivity athigh temperature range. ZT of La1-xPbxCuSeO and LaCuSeO is almost at the similarlevel. It enhances a little ZT of LaCuSeO by Pb doping.