Jung, Sung-Jin Lee, Byeong-Hyeon Kim, Byung Kyu Lim, Sang-Soon Kim, Seong Keun Kim, Dong-Ik Won, Sung Ok Park, Hyung-Ho Kim, Jin-Sang Baek, Seung-Hyub 2024-01-19T22:34:53Z 2024-01-19T22:34:53Z 2021-09-03 2018-05 1359-6454 https://pubs.kist.re.kr/handle/201004/121397 Precise control of carrier density is essential to synthesize high-performance thermoelectric materials. Doping by impurities is often frustrated in n-type Bi2Te3 alloys by incomplete activation, bipolar doping, the formation of secondary phases, and prevailing intrinsic point defects such as vacancies. This weakens the reproducibility of synthesis processes and reduces the long-term reliability of material's performance, hence aging. Here, we explore an impurity-free doping technique to synthesize n-type bismuth tellurium selenides, combining a cold deformation and a hot extrusion. The cold deformation enables controlling the electron density in the range of similar to 10(19)/cm(3) via the formation of intrinsic point defects, and the hot extrusion allows texturing the microstructure to enhance the electrical conductivity, hence a large power factor of >5 x 10(-3) W-m(-1)-K-2. We confirm that our process is very reproducible, and the properties of the samples are stable without aging even after thermal stresses. Using this method, we can decouple the relationship between bandgap, carrier density, and composition to improve the high temperature thermoelectric property. Moreover, we demonstrate the fabrication of high-performance thermoelectric materials from low-graded, raw materials by modifying the degree of the mechanical deformation to reach an optimum carrier density. Our work provides a promising approach to synthesizing n-type thermoelectric materials in the reproducible and adaptable way. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi2Te3-based thermoelectric alloys Article 10.1016/j.actamat.2018.02.061 1 ACTA MATERIALIA, v.150, pp.153 - 160 ACTA MATERIALIA 150 153 160 N scie scopus 000433272400014 2-s2.0-85043571863 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article HIGH-PERFORMANCE ELECTRICAL-PROPERTIES TRANSPORT-PROPERTIES CU ADDITION COPPER BI-2(TE,SE)(3) INTERCALATION DEFORMATION DIFFUSION