Realizing n-type GeSe thermoelectrics:boosting solubility of donor dopants by enhancing crystal symmetry  

作　　者：Xiao-Huan Luo Jia-Hui Cheng Bing-Cai Duan Mo-Ran Wang Yu-Wei Zhou Tu Lyu Chao-Hua Zhang Sheng-Nan Zhang Fu-Sheng Liu Li-Peng Hu 

机构地区：[1]Shenzhen Key Laboratory of Special Functional Materials,Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Guangdong Research Center for Interfacial Engineering of Functional Materials,College of Materials Science and Engineering,Institute of Deep Earth Sciences and Green Energy,Shenzhen University,Shenzhen,518060,China [2]Superconducting Materials Research Center,Northwest Institute for Nonferrous Metal Research,Xi’an,710016,China

出　　处：《Rare Metals》2024年第12期6583-6595,共13页稀有金属(英文版)

基　　金：financially supported by the National Key R&D Program of China(No.2021YFB1507403);the National Natural Science Foundation of China(No.52071218);Shenzhen Science and Technology Innovation Commission(No.JCYJ20230808105700001);Shenzhen University 2035 Program for Excellent Research(No.00000218)。

摘　　要：The successful deployment of thermoelectric materials necessitates the concurrent development of highperformance p-type and n-type pairs situated within an identical matrix.Nevertheless,limiting by the low dopant solubility,the conventional doping often cannot transfer the Fermi level to the opposite carrier type.Here,the solubility limit of donor dopants was enhanced to achieve n-type GeSe by inducing additional cationic vacancies through raising crystal symmetry.Converting the intrinsic p-type nature of GeSe to n-type poses significant challenges,primarily due to the exceedingly low dopant solubility within its native orthorhombic structure.To overcome this,the In_(2)Te_(3)alloying was initially employed to transition GeSe from orthorhombic to rhombohedral structure,simultaneously generating a large number of Ge vacancies.Following this,the introduction of Pb acts to mitigate the excessive Ge vacancies,steering the material toward a weak p-type character.Crucially,the elevated Ge vacancy concentration serves to extend the solubility limit of Bi donor dopant,which not only promotes the formation of cubic phase,but also enables the p-n type transition.As a result,a peak zT of 0.18 at 773 K was attained for the n-type cubic Ge_(0.55)Bi_(0.2)Pb_(0.2)5Se(In_(2)Te_(3))_(0.1),marking an 18-fold enhancement in comparison with its n-type orthorhombic counterpart.This work attests to the efficacy of introducing vacancies through enhancing crystal symmetry as an effective means to expand dopant solubility,thereby offering valuable insights into the achievement of compatible p-and n-type chalcogenides within the same matrix.

关 键 词：Thermoelectric GeSe Crystal symmetry Cationic vacancy SOLUBILITY 

分 类 号：TB34[一般工业技术—材料科学与工程]