The figure of merit ZT is the direct embodiment of thermoelectric performance for a given material.However,as an indicator of performance improvement,the only ZT value is not good enough to identify its outstanding in...The figure of merit ZT is the direct embodiment of thermoelectric performance for a given material.However,as an indicator of performance improvement,the only ZT value is not good enough to identify its outstanding inherent properties,which are highly sought in thermoelectric community.Here,we utilize one powerful parameter to reveal the outstanding properties of a given material.The weighted mobility is used to estimate the carrier transports of p-type SnS crystals,including the differences in doping level,carrier scattering and electronic band structure.We analyze the difference in carrier scattering mechanism for different crystal forms with the same doping level,then evaluate and confirm the temperature-dependent evolution of electronic band structures in SnS.Finally,we calculate the quality factor B based on the weighted mobility,and establish the relationship between ZT and B to further predict the potential performance in p-type SnS crystals with low cost and earth abundance,which can be realized through taking advantage of the inherent material property,thus improving B factor to achieve optimal thermoelectric level.展开更多
It is reported that SnSe_(2) consisting of the same elements as SnSe, is a new promising thermoelectric material with advantageous layered structure. In this work, the thermoelectric performance of polycrystalline SnS...It is reported that SnSe_(2) consisting of the same elements as SnSe, is a new promising thermoelectric material with advantageous layered structure. In this work, the thermoelectric performance of polycrystalline SnSe_(2) is improved through introducing SnSe phase and electron doping(Cl doped in Se sites). The anisotropic transport properties of SnSe_(2) are investigated. A great reduction of the thermal conductivity is achieved in SnSe_(2) through introducing SnSe phase, which mainly results from the strong SnSe_(2)–SnSe inter-phase scattering. Then the carrier concentration is optimized via Cl doping, leading to a great enhancement of the electrical transport properties, thus an extraordinary power factor of ^5.12 μW·cm^(-1)·K^(-2) is achieved along the direction parallel to the spark plasma sintering(SPS) pressure direction( P). Through the comprehensive consideration on the anisotropic thermoelectric transport properties, an enhanced figure of merit ZT is attained and reaches to ^ 0.6 at 773 K in SnSe_(2)-2% SnSe after 5% Cl doping along the P direction, which is much higher than ^ 0.13 and ^ 0.09 obtained in SnSe_(2)-2% SnSe and pristine SnSe_(2) samples, respectively.展开更多
基金Supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0702100 and 2018YFB0703600)the National Natural Science Foundation of China(Grant Nos.51632005 and 51772012)+3 种基金the Beijing Natural Science Foundation(Grant No.JQ18004)the Shenzhen Peacock Plan Team(Grant No.KQTD2016022619565991)111 Project(Grant No.B17002)the National Science Fund for Distinguished Young Scholars(Grant No.51925101).
文摘The figure of merit ZT is the direct embodiment of thermoelectric performance for a given material.However,as an indicator of performance improvement,the only ZT value is not good enough to identify its outstanding inherent properties,which are highly sought in thermoelectric community.Here,we utilize one powerful parameter to reveal the outstanding properties of a given material.The weighted mobility is used to estimate the carrier transports of p-type SnS crystals,including the differences in doping level,carrier scattering and electronic band structure.We analyze the difference in carrier scattering mechanism for different crystal forms with the same doping level,then evaluate and confirm the temperature-dependent evolution of electronic band structures in SnS.Finally,we calculate the quality factor B based on the weighted mobility,and establish the relationship between ZT and B to further predict the potential performance in p-type SnS crystals with low cost and earth abundance,which can be realized through taking advantage of the inherent material property,thus improving B factor to achieve optimal thermoelectric level.
基金supported by the Beijing Natural Science Foundation,China (Grant No. JQ18004)the National Key Research and Development Program of China(Grant Nos. 2018YFA0702100 and 2018YFB0703600)+5 种基金the National Natural Science Foundation of China (Grant No. 51772012)Shenzhen Peacock Plan Team (Grant No. KQTD2016022619565991)111 Project (Grant No. B17002)supported by the National Postdoctoral Program for Innovative Talents,China (Grant No. BX20200028)the high performance computing (HPC) resources at Beihang Universitythe support from the National Science Fund for Distinguished Young Scholars (Grant No. 51925101)。
文摘It is reported that SnSe_(2) consisting of the same elements as SnSe, is a new promising thermoelectric material with advantageous layered structure. In this work, the thermoelectric performance of polycrystalline SnSe_(2) is improved through introducing SnSe phase and electron doping(Cl doped in Se sites). The anisotropic transport properties of SnSe_(2) are investigated. A great reduction of the thermal conductivity is achieved in SnSe_(2) through introducing SnSe phase, which mainly results from the strong SnSe_(2)–SnSe inter-phase scattering. Then the carrier concentration is optimized via Cl doping, leading to a great enhancement of the electrical transport properties, thus an extraordinary power factor of ^5.12 μW·cm^(-1)·K^(-2) is achieved along the direction parallel to the spark plasma sintering(SPS) pressure direction( P). Through the comprehensive consideration on the anisotropic thermoelectric transport properties, an enhanced figure of merit ZT is attained and reaches to ^ 0.6 at 773 K in SnSe_(2)-2% SnSe after 5% Cl doping along the P direction, which is much higher than ^ 0.13 and ^ 0.09 obtained in SnSe_(2)-2% SnSe and pristine SnSe_(2) samples, respectively.
