有机纳米颗粒复合Co掺杂ZnO热电性能研究

Thermoelectric properties of Co-doped ZnO by incorporating organic nanoparticles

摘要:

有机-无机纳米结两端有机材料的离散轨道能级与无机半导体的连续能带差异减小时,使得纳米结界面具有选择性散射不同能量载流子的特征,有利于提高赛贝克系数和热电性能。本文利用溶胶-凝胶法合成了具有有机-无机纳米结结构的聚对苯撑(PPP)纳米复合Zn_1-xCo_xO材料。研究结果表明,较高电导率和赛贝克系数使Zn_0.925Co_0.075O/9 wt% PPP呈现较大的功率因子。另外,有机-无机纳米界面上的界面散射大大降低了热导率。因而,合成的纳米复合材料最大ZT值达到0.22,是Zn_0.925Co_0.075O基体材料的5倍。这一实验结果表明纳米结效应是提高块体热电材料热电性能的有效途径。

Abstract:

Organic-inorganic nanojunction can results in a selective scattering of charge carrier depending on their energy, which leads to a simultaneous increase in Seebeck coefficient S and power factor PF when the Fermi levels of the constituent materials are aligned appropriately. In this work, the nanojunction was successfully employed at the organic-inorganic semiconductor interface of polyparaphenylene (PPP) and Zn_1-xCo_xO nanoparticles through sol-gel method. The resulting Zn_0.925Co_0.075O/9 wt% PPP hybrids exhibited a high power factor due to the largest electrical conductivity and higher Seebeck coefficient. Moreover, organic-inorganic nano-interface effectively reduces the thermal conductivity by interface scattering of phonons. All these effects finally lead to a thermoelectric figure of merit, ZT up to 0.22 in these inorganic-organic nanocomposites, which corresponds to a 5-fold enhancement compared to that of the Zn_0.925Co_0.075O matrix. This work demonstrates the effectiveness of nanojunctions and provides a rational route to high performance thermoelectrics in a bulk material.