As a typical IV-VI compound,SnTe has aroused widely attentions in the thermoelectric community due its similar crystal and band structures with PbTe.However,both the large number of inherent Sn vacancies and high ther...As a typical IV-VI compound,SnTe has aroused widely attentions in the thermoelectric community due its similar crystal and band structures with PbTe.However,both the large number of inherent Sn vacancies and high thermal conductivity result in inferior thermoelectric performance in intrinsic SnTe over a broad temperature.In this work,we successfully improved those disadvantages of SnTe via stepwisely Pb heavily alloying and then In doping.A significantly wide fraction of Pb into SnTe(0-50%)achieves multiple effects:(a)the carrier concentration of SnTe is reduced through decreasing Sn vacancies via alloying high solution Pb atoms in the matrix;(b)the band structure is optimized through promoting the convergence of the two valence bands,simultaneously enhancing the Seebeck coefficient;(c)HAADF-STEM coupled with EDS results illustrate that guest Pb atoms randomly and uniformly occupied Sn atomic sites in the matrix,concurrently strengthening the phonon scattering.Furthermore,we introduced indium into Sn_(0.6)Pb_(0.4)Te system to create resonant states further enlarging the power factors at low-medium temperature.The integration of bands convergence and DOS distortion achieves a considerably high ZT_(ave) of~0.67 over the wide temperature range of 300-823 K in(Sn_(0.6)Pb_(0.4))_(0.995)In_(0.005)Te sample.展开更多
基金supported by the National Key Research and Development Program of China(2018YFA0702100 and 2018YFB0703600)National Natural Science Foundation of China(51772012,51671015,52002011,52002042 and 61974042)+5 种基金Beijing Natural Science Foundation(JQ18004)National Training Program of Innovation and Entrepreneurship for undergraduates(202010006002)National Postdoctoral Programfor Innovative Talents(BX20200028)the support from the National Science Fund for Distinguished Young Scholars(51925101)the high performance computing(HPC)resources at Beihang Universitysupported by Natural Science Foundation of Chongqing,China,cstc2019jcyj-msxmX0554.
文摘As a typical IV-VI compound,SnTe has aroused widely attentions in the thermoelectric community due its similar crystal and band structures with PbTe.However,both the large number of inherent Sn vacancies and high thermal conductivity result in inferior thermoelectric performance in intrinsic SnTe over a broad temperature.In this work,we successfully improved those disadvantages of SnTe via stepwisely Pb heavily alloying and then In doping.A significantly wide fraction of Pb into SnTe(0-50%)achieves multiple effects:(a)the carrier concentration of SnTe is reduced through decreasing Sn vacancies via alloying high solution Pb atoms in the matrix;(b)the band structure is optimized through promoting the convergence of the two valence bands,simultaneously enhancing the Seebeck coefficient;(c)HAADF-STEM coupled with EDS results illustrate that guest Pb atoms randomly and uniformly occupied Sn atomic sites in the matrix,concurrently strengthening the phonon scattering.Furthermore,we introduced indium into Sn_(0.6)Pb_(0.4)Te system to create resonant states further enlarging the power factors at low-medium temperature.The integration of bands convergence and DOS distortion achieves a considerably high ZT_(ave) of~0.67 over the wide temperature range of 300-823 K in(Sn_(0.6)Pb_(0.4))_(0.995)In_(0.005)Te sample.
