Abstract
As a sister compound of PbTe,SnTe possesses the environmentally friendly elements.However,the pristine SnTe compounds suffer from the high carrier concentration,the large valence band offset between the L and ∑positions and high thermal conductivity.Using high-pressure and high-temperature technology,we synthesized the pristine SnTe samples at different pressures and systemically investigated their thermoelectric properties.High pressure induces rich microstructures,including the high-density dislocations and lattice distortions,which serve as the strong phonon scattering centers,thereby reducing the lattice thermal conductivity.For the elec-trical properties,pressure reduces the harmful high carrier concentration,due to the depression of Sn vacancies.Moreover,pressure induces the valence band convergence,reducing the energy separation between the L and ∑positions.The band convergence and suppressed carrier concentration increase the Seebeck coefficient.Thus,the power factors of pressure-sintered compounds do not deteriorate significantly under the condition of decreasing electrical conductivity.Ultimately,for a pristine SnTe compound synthesized at 5 GPa,a higher ZT value of 0.51 is achieved at 750 K,representing a 140％improvement compared to the value of 0.21 obtained using SPS.There-fore,the high-pressure and high-temperature technology is demonstrated as an effectively approach to optimize thermoelectric performance.
基金项目
国家自然科学基金(12374012)
国家自然科学基金(11974208)
国家自然科学基金(52172212)
国家自然科学基金(52002217)
山东省自然科学基金(ZR2023JQ001)
山东省自然科学基金(ZR2020YQ05)
山东省自然科学基金(2019KJJ020)
Program of Distinguished Expert of Taishan Scholar(tstp20221124)
NETL
NSTL
万方数据