物理学报2025，Vol.74Issue(10)：252-262,11.DOI:10.7498/aps.74.20250150
p型BixSb2-xTe3-ySey基材料低温热电性能
Low-temperature thermoelectric properties of p-type BixSb2-xTe3-ySey-based materials
摘要
Abstract
Bi2Te3-based compounds are the thermoelectric materials available only commercially,but the research on their low-temperature performances below 300 K are still insufficient.The influences of Bi/Sb ratio modulation and Se substitution on the electrical and thermal transport properties of BixSb2-xTe3 and Bi0.4Sb1.6Te3-ySey materials are systematically investigated in this work,aiming to optimize their thermoelectric performance in cryogenic regions through combined bandgap tuning and defect engineering.Materials are synthesized using a melt-quenching and spark plasma sintering process,and then phase analysis is conducted via X-ray diffraction and microstructural characterization by electron probe microanalysis.First-principles calculations and Hall effect measurements are used to investigate their defect formation mechanisms and carrier transport behaviors.In the BixSb2-xTe3 system,the increase of Bi content reduces the bandgap from 0.168 eV for Bi0.4Sb1.6Te3 to 0.113 eV for Bi0.58Sb1.42Te3,shifting the peak ZT temperature to lower ranges.However,the enhancement of alloy scattering leads the carrier mobility to decrease from 332 to 109 cm2/(V·s)and power factor to fall from 4.58 to 1.12 mW/(m·K2).To solve this problem,Se is substituted for the Te lattice of Bi0.4Sb1.6Te3.First-principles calculations reveal that the Se substitution reduces the formation energy of SeTe+BiSb complex,thus effectively suppressing SbTe antisite defects.This will result in the carrier concentration decreasing from 3.32 ×1019 to 2.64×1019 cm-3 while maintaining high mobility at 279 cm2/(V·s).Concurrently,Se-induced point defects enhance phonon scattering,reducing lattice thermal conductivity from 0.46 to 0.38 W/(m·K),a decrease of 17％.Bi0.4Sb1.6Te2.97Se0.03 sample achieves a ZT value of 0.93 at 220 K,which is 16％higher than the pristine Bi0.4Sb1.6Te3 sample with a ZT value of 0.80.The peak ZT increases from 1.17 to 1.31 at 350 K,an increase of 12％.These improvements arise from the synergistic effects of band engineering,where flattened valence band edges increase effective mass,and defect engineering,where antisite defects and strengthens phonon scattering are suppressed.This work provides a dual optimization strategy for BiSbTe-based materials,i.e.balancing bandgap reduction by controlling defects to improve cryogenic performance.The findings are particularly significant for the applications of BiSbTe-based materials in infrared detectors and multistage thermoelectric cooling systems.关键词
Bi2Te3基化合物/低温热电性能/能带工程/缺陷工程Key words
Bi2Te3-based compounds/low-temperature thermoelectric properties/band engineering/defect engineering引用本文复制引用
钟文龙,李珺杰,刘可可,郜顺奇,吴明轩,李貌,苏贤礼,张清杰,唐新峰..p型BixSb2-xTe3-ySey基材料低温热电性能[J].物理学报,2025,74(10):252-262,11.基金项目
国家重点研发计划(批准号:2024YFF0505900)和国家自然科学基金(批准号:W2412066)资助的课题. Project supported by the National Key Research and Development Program of China(Grant No.2024YFF0505900)and the National Natural Science Foundation of China(Grant No.W2412066). （批准号:2024YFF0505900）
