Lead-free halide perovskites provide a promising solution for efficient thermoelectric materials due to their ultralow lattice thermal conductivity(κ_(L)).However,disadvantages such as the electrically resistive natu...Lead-free halide perovskites provide a promising solution for efficient thermoelectric materials due to their ultralow lattice thermal conductivity(κ_(L)).However,disadvantages such as the electrically resistive nature strongly affect their power factor.In this work,we introduced the Te-based halide perovskites thermoelectric material Cs_(2)TeI_(6),which is already known as a promising candidate for photovoltaic applications due to its moderate band gap.Our findings reveal that Cs_(2)TeI_(6)has an exceptionally ultralow κ_(L)at room temperature,reaching as low as 0.17 W·m^(-1)·K^(-1).We found that the four-phonon scattering processes play a dominant role in suppressing the thermal transport,leading to an approximate 50% reduction in its particle-like thermal conductivity κ_(p) at 300 K.The ultralow κ_(L)can be mainly attributed to the strong discrepancy in bonding strength,which induces large anharmonicity.The flat and dense phonon dispersions result in a strong phonon scattering rate,making it easy to generate wavelike phonon tunneling.After accounting for the wavelike thermal conductivity κ_(c),a nonstandard T^(-0.30)temperature dependence was observed.Benefiting from the ultralow κ_(L),n-type Cs_(2)TeI_(6)is predicted to achieve an extraordinary ZT of 2.26 at 700 K.This work highlights a pathway for searching high-performance and low-cost thermoelectrics based on lead-free halide perovskites.展开更多
We present a comprehensive study on the individual sources of an inclusive photon production during high-energy hadronic collisions.The cross section and invariant yields of inclusive photons are obtained as a functio...We present a comprehensive study on the individual sources of an inclusive photon production during high-energy hadronic collisions.The cross section and invariant yields of inclusive photons are obtained as a function of pT at mid-rapidity(|y|<0.5)in p+p and Au+Au collisions at√SNN=200GeVrespectively.These results provide crucial inputs to separate measurements of open bottom and charm hadron yield suppression in heavyion collisions,which are used to test the mass hierarchy of the parton energy loss in the quark gluon plasma created during these collisions.The procedure developed in this study can also be applied to other measurements of electrons from an open heavy-flavor hadron decay,such as the collective flow in the RHIC beam energy scan program.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12204482 and U2330104)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2020L0537)+2 种基金the Natural Science Foundation of Shanxi Province(Grant No.202403021221164)Higher Education Teaching Reform and Innovation Project of Shanxi Province(Grant No.J20220480)Graduate Curriculum Ideological and Political Education Project of Shanxi Normal University(Grant No.010520233013)。
文摘Lead-free halide perovskites provide a promising solution for efficient thermoelectric materials due to their ultralow lattice thermal conductivity(κ_(L)).However,disadvantages such as the electrically resistive nature strongly affect their power factor.In this work,we introduced the Te-based halide perovskites thermoelectric material Cs_(2)TeI_(6),which is already known as a promising candidate for photovoltaic applications due to its moderate band gap.Our findings reveal that Cs_(2)TeI_(6)has an exceptionally ultralow κ_(L)at room temperature,reaching as low as 0.17 W·m^(-1)·K^(-1).We found that the four-phonon scattering processes play a dominant role in suppressing the thermal transport,leading to an approximate 50% reduction in its particle-like thermal conductivity κ_(p) at 300 K.The ultralow κ_(L)can be mainly attributed to the strong discrepancy in bonding strength,which induces large anharmonicity.The flat and dense phonon dispersions result in a strong phonon scattering rate,making it easy to generate wavelike phonon tunneling.After accounting for the wavelike thermal conductivity κ_(c),a nonstandard T^(-0.30)temperature dependence was observed.Benefiting from the ultralow κ_(L),n-type Cs_(2)TeI_(6)is predicted to achieve an extraordinary ZT of 2.26 at 700 K.This work highlights a pathway for searching high-performance and low-cost thermoelectrics based on lead-free halide perovskites.
基金This work was supported by National Key Research and Development Program of China(Nos.2018YFE0205200,2018YFE0104700,and 2020YFE0202002)National Natural Science Foundation of China(No.11890712)+2 种基金Natural Science Foundation of Anhui Province(No.1808085J02)Fundamental Research Funds for the Central Universities(No.WK2030000013)the Project funded by the China Postdoctoral Science Foundation(No.2019M652177).
文摘We present a comprehensive study on the individual sources of an inclusive photon production during high-energy hadronic collisions.The cross section and invariant yields of inclusive photons are obtained as a function of pT at mid-rapidity(|y|<0.5)in p+p and Au+Au collisions at√SNN=200GeVrespectively.These results provide crucial inputs to separate measurements of open bottom and charm hadron yield suppression in heavyion collisions,which are used to test the mass hierarchy of the parton energy loss in the quark gluon plasma created during these collisions.The procedure developed in this study can also be applied to other measurements of electrons from an open heavy-flavor hadron decay,such as the collective flow in the RHIC beam energy scan program.
