Optimized Mn and Bi co-doping in SnTe based thermoelectric material:A case of band engineering and density of states tuning  

作　　者：Samuel Kimani Kihoi Joseph Ngugi Kahiu Hyunji Kim U.Sandhya Shenoy D.Krishna Bhat Seonghoon Yi Ho Seong Lee 

机构地区：[1]School of Materials Science and Engineering,Kyungpook National University,80 Daehak-ro,Buk-gu,Daegu 41566,Republic of Korea [2]Department of Hydrogen and Renewable Energy,Kyungpook National University,80 Daehak-ro,Buk-gu,Daegu 41566,Republic of Korea [3]Department of Chemistry,College of Engineering and Technology,Srinivas University,Mukka,574146 Mangalore,Karnataka,India [4]Department of Chemistry,National Institute of Technology Karnataka,Surathkal,Srinivasnagar,575025 Mangalore,Karnataka,India

出　　处：《Journal of Materials Science & Technology》2021年第26期76-86,共11页材料科学技术（英文版）

基　　金：supported by grants from the National Research Foundation(NRF)of Korea(No.2018R1A41A1022260),funded by the Korean government(MSIT);the grant in the form of DST INSPIRE Faculty award from Department of Science and Technology,Government of India。

摘　　要：Tin telluride(SnTe)overwhelmingly continues to be studied owing to its promising thermoelectric properties,tunable electronic structure,and its potential as an alternate to toxic lead telluride(PbTe)based materials.In this research,we engineer the electronic properties of SnTe by co-doping Mn and Bi below their individual solubility limit.The First principles density functio nal theory studies reveal that both Bi and Mn introduce resonance states,thereby increasing the density of states near the Fermi level leading to enhanced Seebeck coefficient.This unique combination of using two resonant dopants to introduce flatter bands is effective in achieving higher performance at lower tempe ratures manifesting into a large Seebeck value of~91μV/K at room temperature in the present case.Both elements optimally co-doped results in a very high power factor value of~24.3μW/cmK^(2) at 773 K when compared to other high performance SnTe based materials.A zT of~0.93 at 773 K is achieved by tuning the proportion of the co-dopants Mn and Bi in SnTe.The hardness value of pristine SnTe was also seen to increase after doping.As a result,synergistic optimized doping proves to be a suitable means for obtaining thermoelectric materials of superior characteristics without the need for heavy doping.

关 键 词：SnTe THERMOELECTRIC Electronic structure engineering SOLUBILITY Thermal conductivity 

分 类 号：TB34[一般工业技术—材料科学与工程]