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Nanostructuring materials using solution synthesis approach for high performance thermoelectric devices

Title
Nanostructuring materials using solution synthesis approach for high performance thermoelectric devices
Translated Title
높은 성능의 열전소자 제작을 위한 용액공정의 나노 구조화 물질 개발
Authors
Jeong, Soo Yeol
DGIST Authors
Jeong, Soo Yeol; Lee, Jong Soo; Lee, Jae Dong
Advisor(s)
Lee, Jong Soo
Co-Advisor(s)
Lee, Jae Dong
Issue Date
2016
Available Date
2016-02-12
Degree Date
2016. 2
Type
Thesis
Keywords
thermoelectricnanocrystalsBi0.5Sb1.5Te3argyroditecolloidal solution synthesis콜로이드 용액 합성열전소자나노입자
Abstract
Recently a few years thermoelectric research area have focused on nanosize materials to break through the limit of figure of merit above the 3 for boosting commercialization. We also jumped on the field with two chemical approaches. At the first, we induce the gold particles and combine with existing thermoelectric materials. In particularly, Bi0.5Sb1.5Te3 which is already well-known high performance p type thermoelectric materials at room temperature is sintered with spark plasma sintering (SPS) and hot pressing sintering (HPS) at different temperature. Gold doping compound are shown high carrier concentration due to substitution defect. Therefore high Au containing can affect to get large electrical conductivity around 7.8×104S/m SPS Au 2wt% compound and 13.5×104S/m HPS Au 2wt%. We demonstrated anisotropic properties of Bi0.5Sb1.5Te3 and compare between SPS and HPS compounds depending on temperature. Second strategy is bottom up using colloid solution synthesis process for thermoelectric materials. We focus on the argyrodite crystal which is well known ultra low thermal conductivity to check the nano sizing effect. Here, we reported a new facile synthesis way to fabricate the colloidal Ag8SnSe6 nanocrystals and characterization nanocrystals. ⓒ 2016 DGIST
Table Of Contents
1. Introduction 1 -- 2. Theoretical background 5 -- 2.1. Quantum Dots 5 -- 2.1.1. Quantum confinement effect 5 -- 2.2. Thermoelectric 6 -- 2.2.1. Relation among the thermoelectric coefficient 6 -- 2.2.2. The figure of merit 6 -- 3. Experiments 8 -- 3.1. Synthesis of Bi0.5Sb1.5Te3 with gold 8 -- 3.1.1. Chemicals 8 -- 3.1.2. Ligand exchange 8 -- 3.1.3. Sintering process 9 -- 3.2. A facile synthesis of Ag8SnSe6 nanocrystals 9 -- 3.2.1. Chemicals 9 -- 3.2.2. Synthesis of Ag8SnSe6 nanocrystals 10 -- 3.2.3. Synthesis of Ag8SnS6 nanocrystals 10 -- 3.2.4. Gram-scale synthesis of Ag8SnSe6 nanocrystals 11 -- 3.3. Characterization and measurement 12 -- 4. Results & Discussion 13 -- 4.1. The effect of Au particle and sintering condition on Bi0.5Sb1.5Te3 thermoelectric properties 13 -- 4.2. A facile synthesis of Ag8SnSe6 nanocrystals 31 -- 4.2.1. A new synthesis way of colloid Ag8SnSe6 nanoparticles 31 -- 4.2.2. A modifying synthesis method of colloid Ag8SnS6 nanoparticles 34 -- 5. Summary & conclusion 37 -- 6. References 38--
URI
http://dgist.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002225903
http://hdl.handle.net/20.500.11750/1467
DOI
10.22677/thesis.2225903
Degree
Master
Department
Energy Systems Engineering
University
DGIST
Files:
Collection:
Energy Systems EngineeringThesesMaster


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