Element doping and nano-inclusion embedding are effective approaches to enhance the electrical conductivities and decrease the lattice thermal conductivities of thermoelectric(TE)materials,respectively.However,the int...Element doping and nano-inclusion embedding are effective approaches to enhance the electrical conductivities and decrease the lattice thermal conductivities of thermoelectric(TE)materials,respectively.However,the intrinsic low electrical thermal conductivities and high electrical properties are severely sacrificed,and the final figure of merit(ZT)is usually restricted.In this study,Ag doping and Pt quantum dot(QD)embedding were synchronously achieved via embedding Ag/Pt alloy QDs into the higher manganese silicides to avoid the conventional single-element doping strategy.The power factor(at 823 K)was enhanced from 1.57×10^(-3) W m^(-1) K^(-2) to 1.82×10^(-3) W m^(-1) K^(-2)(-16%)due to the-18%increase in carrier concentration that was derived from the Ag doping effect.Simultaneously,the lattice thermal conductivity(at 823 K)decreased from 2.65 W m^(-1) K^(-1) e1.92 W m^(-1) K^(-1)(-28%)because of the broadband phonon scattering effect that resulted from the residual Pt QDs inclusions.Synthetically,the optimal ZT value increased by-52%from 0.42 to 0.64 at 823 K.This study demonstrated that incorporating metastable alloy QDs to obtain element doping and nano-inclusion embedding effects is a novel and feasible means to enhance the ZT value of HMS.This method is also possibly applicable to other alloy QD/TE composites.展开更多
Higher manganese silicide(HMS)is a P-type medium temperature thermoelectric(TE)material,which has attracted widespread attention over the past few decades due to its remarkable mechanical properties,excellent chemical...Higher manganese silicide(HMS)is a P-type medium temperature thermoelectric(TE)material,which has attracted widespread attention over the past few decades due to its remarkable mechanical properties,excellent chemical and thermal stability,as well as the non-toxicity,abundance and competitive price.The peak power factor(PF)of HMS is as high as~1.50×10^(-3)W m^(-1)K^(-2)because of its intrinsic high electrical conductivity and Seebeck coefficient.However,the thermal conductivity of HMS is also high,resulting in relatively low z T values.Introducing nano-dispersion in the matrix is one of the most effective methods to enhance the TE properties via reducing the lattice thermal conductivity significantly without drastic changes on the other parameters.In this study,Cs Pb BrQDs with uniform size were synthesized and introduced into HMS bulks.The PF(at 823 K)was enhanced to 1.71×10^(-3)W m^(-1)K^(-2),which is improved 14.0%approximately compared with that of pure HMS owing to the combined effect of element doping and energy filtering.The lattice thermal conductivity(at 823 K)decreased from 2.56W mKto 1.99 W mKsynchronously(~22.0%)due to the intensive phonon scattering caused by Cs doping,and the embedding of Pb riched CsPbBr_(3)QDs and Pb QDs.A maximum z T value of 0.57(823 K)is achieved in Cs Pb BrQDs/HMS composites,which is 36.0%higher than that of pure HMS.Predictably,for other TE materials,it is also feasible to improve the TE properties via introducing metastable quantum dots.展开更多
基金supported by the National Science Foundation for Young Scientists of China(51802071)Advanced Talents Incubation Program of the Hebei University(521000981162)+3 种基金Outstanding Youth Science Foundation project of Hebei Province(A2020201032)Local Science and Technology Development Fund Projects Guided by the Central Government(206Z4403G)National Natural Science Foundation of China(No.51372064)Hebei Province High-level Talents Funding project(No.A201801003).
文摘Element doping and nano-inclusion embedding are effective approaches to enhance the electrical conductivities and decrease the lattice thermal conductivities of thermoelectric(TE)materials,respectively.However,the intrinsic low electrical thermal conductivities and high electrical properties are severely sacrificed,and the final figure of merit(ZT)is usually restricted.In this study,Ag doping and Pt quantum dot(QD)embedding were synchronously achieved via embedding Ag/Pt alloy QDs into the higher manganese silicides to avoid the conventional single-element doping strategy.The power factor(at 823 K)was enhanced from 1.57×10^(-3) W m^(-1) K^(-2) to 1.82×10^(-3) W m^(-1) K^(-2)(-16%)due to the-18%increase in carrier concentration that was derived from the Ag doping effect.Simultaneously,the lattice thermal conductivity(at 823 K)decreased from 2.65 W m^(-1) K^(-1) e1.92 W m^(-1) K^(-1)(-28%)because of the broadband phonon scattering effect that resulted from the residual Pt QDs inclusions.Synthetically,the optimal ZT value increased by-52%from 0.42 to 0.64 at 823 K.This study demonstrated that incorporating metastable alloy QDs to obtain element doping and nano-inclusion embedding effects is a novel and feasible means to enhance the ZT value of HMS.This method is also possibly applicable to other alloy QD/TE composites.
基金financially supported by the National Science Foundation for Young Scientists of China(No.51802071)the Advanced Talent Incubation Program of Hebei University(No.521000981162)+4 种基金the Outstanding Youth Science Foundation project of Hebei Province(No.A2020201032)the Local Science and Technology Development Fund Projects Guided by the Central Government(Nos.206Z4403G and 042000520091)the National Natural Science Foundation of China(No.51372064)the Hebei Province High-level Talents Funding project(No.A201801003)supported in part by the Microanalysis Center and the High-Performance Computing Center of Hebei University。
文摘Higher manganese silicide(HMS)is a P-type medium temperature thermoelectric(TE)material,which has attracted widespread attention over the past few decades due to its remarkable mechanical properties,excellent chemical and thermal stability,as well as the non-toxicity,abundance and competitive price.The peak power factor(PF)of HMS is as high as~1.50×10^(-3)W m^(-1)K^(-2)because of its intrinsic high electrical conductivity and Seebeck coefficient.However,the thermal conductivity of HMS is also high,resulting in relatively low z T values.Introducing nano-dispersion in the matrix is one of the most effective methods to enhance the TE properties via reducing the lattice thermal conductivity significantly without drastic changes on the other parameters.In this study,Cs Pb BrQDs with uniform size were synthesized and introduced into HMS bulks.The PF(at 823 K)was enhanced to 1.71×10^(-3)W m^(-1)K^(-2),which is improved 14.0%approximately compared with that of pure HMS owing to the combined effect of element doping and energy filtering.The lattice thermal conductivity(at 823 K)decreased from 2.56W mKto 1.99 W mKsynchronously(~22.0%)due to the intensive phonon scattering caused by Cs doping,and the embedding of Pb riched CsPbBr_(3)QDs and Pb QDs.A maximum z T value of 0.57(823 K)is achieved in Cs Pb BrQDs/HMS composites,which is 36.0%higher than that of pure HMS.Predictably,for other TE materials,it is also feasible to improve the TE properties via introducing metastable quantum dots.
