Isovalent co-alloying contributes to considerable improvement in thermoelectric performance of BiSe bulks with weak anisotropy  

作　　者：Fu Li Chen Liu Mohammad Nisar Jian Zhao Chongbin Liang Junze Zhang Ziyuan Wang Zhuanghao Zheng Ping Fan Xilin Wang Zhen-Hua Ge Yue-Xing Chen 

机构地区：[1]Shenzhen Key Laboratory of Advanced Thin Films and Applications,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province,College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen,518060,Guangdong,China [2]Kunming University of Science and Technology,Kunming,650093,China [3]Tsinghua Shenzhen International Graduate School,Tsinghua University,Shenzhen,518060,Guangdong,China

出　　处：《Journal of Materiomics》2024年第5期965-974,共10页无机材料学学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.52372210 and No.52072248);Natural Science Foundation of Guangdong Province of China(No.2023A1515010122 and No.2021A1515012128);Technology plan project of Shenzhen(No.20220810154601001).

摘　　要：BiSe with intrinsic low thermal conductivity has considered as a promising thermoelectric(TE)material at nearly room temperature.To improve its low thermoelectric figure of merit(zT),in this work,Sb and Te isovalent co-alloying was performed and significantly optimized its TE property with weakly anisotropic characteristic.After substituting Sb on Bi sites,the carrier concentration is suppressed by introduction of Sbsingle bond Se site defects,which contributes to the increased absolute value of Seebeck coefficient(|S|).Further co-alloying Te on Se of the optimized composition Bi_(0.7)Sb_(0.3)Se,the carrier concentration increased without affecting the|S|due to the enhanced effective mass,which leads to a highest power factor of 12.8μW/(cm·K^(2))at 423 K.As a result,a maximum zT of∼0.54 is achieved for Bi_(0.7)Sb_(0.3)Se_(0.7)Te_(0.3) along the pressing direction and the average zT(zTave)(from 300 K to 623 K)are drastically improved from 0.24 for pristine BiSe sample to 0.45.Moreover,an energy conversion efficiency∼4.0%is achieved for a single leg TE device of Bi_(0.7)Sb_(0.3)Se_(0.7)Te_(0.3)when applied the temperature difference of 339 K,indicating the potential TE application.

关 键 词：BiSe Isovalent alloying ZT Carrier modulation 

分 类 号：TG14[一般工业技术—材料科学与工程]