Tang Chunmei, Huang Zhicheng, Pei Jun, Zhang Bo-Ping, Shang Peng-Peng, Shan Zhihang, Zhang Zhiyue, Gu Haiyun, Wen Kaibin
The Beijing Municipal Key Laboratory of New Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing Beijing 100083 China
Department of Chemistry and Material Science, Shandong Agricultural University 61 Daizong Road Tai'an Shandong 271018 China.
RSC Adv. 2019 May 8;9(25):14422-14431. doi: 10.1039/c9ra01738k. eCollection 2019 May 7.
Intrinsic BiTe is a representative thermoelectric (TE) material with high performance at low temperature, which enables applications for electronic cooling. However, antisite defects easily form in p-type BiTe, resulting in the difficulty of further property enhancement. In this work, the formation energy of native point defects in BiTe supercells and the electronic structure of BiTe primitive unit cell were calculated using first-principles. The antisite defect Bi_Te has a lower formation energy (0.68 eV) under the Te-lack condition for p-type BiTe. The effects of point defects on TE properties were investigated a series of p-type BiTe ( = 0, 0.02, 0.04, 0.06, 0.08) single crystals prepared by the temperature gradient growth method (TGGM). Apart from the increased power factor (PF) which originates from the increased carrier concentration ( ) and *, the thermal conductivity ( ) was also cut down by the increased point defects. Benefitting from the high PF of 4.09 mW m K and the low of 1.77 W m K, the highest of 0.70 was obtained for = 0.06 composition at 300 K, which is 30% higher than that (0.54) of the intrinsic BiTe.
本征BiTe是一种具有代表性的热电（TE）材料，在低温下具有高性能，可用于电子冷却应用。然而，p型BiTe中容易形成反位缺陷，导致进一步提高性能存在困难。在这项工作中，使用第一性原理计算了BiTe超胞中本征点缺陷的形成能以及BiTe原胞的电子结构。对于p型BiTe，在缺Te条件下，反位缺陷Bi_Te具有较低的形成能（0.68 eV）。通过温度梯度生长法（TGGM）制备了一系列p型BiTe（ = 0, 0.02, 0.04, 0.06, 0.08）单晶，研究了点缺陷对TE性能的影响。除了由于载流子浓度（ ）和*增加而导致功率因子（PF）增加外，点缺陷增加也降低了热导率（ ）。得益于4.09 mW m K的高PF和1.77 W m K的低 ，在300 K时， = 0.06成分的最高 为0.70，比本征BiTe的 （0.54）高30%。
