Organic-Inorganic Hybrid Thermoelectric Material Synthesis and Properties

Kim, Jiwon,Lim, Jae-Hong The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.4

Organic-inorganic hybrid thermoelectric materials have obtained increasing attention because it opens the possibility of enhancing thermoelectric performance by utilizing the low thermal conductivity of organic thermoelectric materials and the high Seebeck coefficient of inorganic thermoelectric materials. Moreover, the organic-inorganic hybrid thermoelectric materials possess numerous advantages, including functional aspects such as flexibility or transparency, low cost raw materials, and simplified fabrication processes, thus, allowing for a wide range of potential applications. In this study, the types and synthesis methods of organic-inorganic thermoelectric hybrid materials were discussed along with the methods used to enhance their thermoelectric properties. As a key factor to maximize the thermoelectric performances of hybrid thermoelectric materials, the nanoengineering to control the nanostructure of the inorganic materials as well as the modification of the organic material structure and doping level are considered, respectively. Meanwhile, the interface between the inorganic and organic phase is also important to develop the hybrid thermoelectric module with excellent reliability and high thermoelectric efficiency in addition to its performance in various electronic devices.

다결정 SnSe 열전 재료의 성능 개선 연구 동향

정명준,최병준 한국분말재료학회 2022 한국분말재료학회지 (KPMI) Vol.29 No.2

Thermoelectric materials can reversely convert heat and electricity into each other; therefore, they can be very useful for energy harvesting from heat waste. Among many thermoelectrical materials, SnSe exhibits outstanding thermoelectric performance along the particular direction of a single crystal. However, single-crystal SnSe has poor mechanical properties and thus it is difficult to apply for mass production. Therefore, polycrystalline SnSe materials may be used to replace single-crystal SnSe by overcoming its inferior thermoelectric performance owing to surface oxidation. Considerable efforts are currently focused on enhancing the thermoelectric performance of polycrystalline SnSe. In this study, we briefly review various enhancement methods for SnSe thermoelectric materials, including doping, texturing, and nano-structuring. Finally, we discuss the future prospects of SnSe thermoelectric powder materials.

Oxidation suppression characteristics of the YSZ coating on Mg₂Si thermoelectric legs

Park, S.H.,Kim, Y.,Yoo, C.Y. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.8

Oxide-based coating layers were investigated to suppress the oxidation of an intermediate temperature thermoelectric module that operates in a temperature range of 300-700<SUP>o</SUP>C. Four different oxides [alumina (Al<SUB>2</SUB>O<SUB>3</SUB>), yttria (Y<SUB>2</SUB>O<SUB>3</SUB>), 8mol% yttria-stabilized zirconia ((Y<SUB>2</SUB>O<SUB>3</SUB>)<SUB>0.08</SUB>(ZrO<SUB>2</SUB>)<SUB>0.92</SUB>, YSZ), and 20mol% samaria-doped ceria (Sm<SUB>0.2</SUB>Ce<SUB>0.8</SUB>O<SUB>1.9</SUB>, SDC)] were coated onto Mg<SUB>2</SUB>Si thermoelectric leg surfaces and their anti-oxidation characteristics were compared. While Al<SUB>2</SUB>O<SUB>3</SUB>, Y<SUB>2</SUB>O<SUB>3</SUB>, and SDC layers failed to prevent the progression of oxidation of the thermoelectric Mg<SUB>2</SUB>Si surface at 700<SUP>o</SUP>C, YSZ showed potential as an anti-oxidation coating layer for intermediate temperature thermoelectric modules. The apparent oxidation suppression characteristics of the YSZ layer on the Mg<SUB>2</SUB>Si thermoelectric material were studied by a microstructural investigation of the interface between the coated layer and the thermoelectric material. The reliability of the YSZ coating structure was investigated via thermal cycling tests from room temperature to 600<SUP>o</SUP>C. The practical adaptability of the YSZ anti-oxidation coating in terms of use for thermoelectric power-generation modules is discussed in detail with the results of variation in contact resistance.

Investigation of the Thermal-to-Electrical Properties of Transition Metal-Sb Alloys Synthesized for Thermoelectric Applications

박종민,조승기,정수호,배진희,Linh Ba Vu,박귀일,김경태 한국분말재료학회 2024 한국분말재료학회지 (KPMI) Vol.31 No.3

The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.

고효율 열전소재 2%Na-PbTe 의 소자화에 관한 연구

김훈 ( Hoon Kim ),강찬영 ( Chan Young Kang ),황준필 ( Junp Hil Hwang ),김우철 ( Woo Chul Kim ) 정보저장시스템학회 2014 정보저장시스템학회논문집 Vol.10 No.2

Heat emission from the laser diode used in the optical disc drive and the defects from the increased temperature at the system have attracted attentions from the field of the information storage device. Thermoelectric refrigerator is one of the fine solutions to solve these thermal problems. The refrigeration performance of thermoelectric device is dependent on the thermoelectric material’s figure-of-merit. Meanwhile, high electrical contact resistivity between metal electrode and p- and n-type thermoelectric materials in the device would lead increased total electrical resistance resulting in the degeneracy in performance. This paper represents the manufacturing process of the PbTebased material which has one of the highest figure-of-merit at medium-high-temperature, ~ 600K to 900 K, and the nickel contact layer for reduced electrical contact resistance at once, and the results showing the decent contact structure and figure-of-merit even after the long-term operation environment.

열간등방가압 공정을 통한 P형 Bi0.5Sb1.5Te3.0 소결체의 격자 열전도도 감소 및 열전 특성 향상

정수호,우예진,김경태,조승기 한국분말재료학회 2023 한국분말재료학회지 (KPMI) Vol.30 No.2

High-temperature and high-pressure post-processing applied to sintered thermoelectric materials can create nanoscale defects, thereby enhancing their thermoelectric performance. Here, we investigate the effect of hot isostatic pressing (HIP) as a post-processing treatment on the thermoelectric properties of p-type Bi0.5Sb1.5Te3.0 compounds sintered via spark plasma sintering. The sample post-processed via HIP maintains its electronic transport properties despite the reduced microstructural texturing. Moreover, lattice thermal conductivity is significantly reduced owing to activated phonon scattering, which can be attributed to the nanoscale defects created during HIP, resulting in an ~18% increase in peak zT value, which reaches ~1.43 at 100oC. This study validates that HIP enhances the thermoelectric performance by controlling the thermal transport without having any detrimental effects on the electronic transport properties of thermoelectric materials.

First principles study of monolayer Sb2S2Te and a mathematical model of a thin-film thermoelectric generator with maximum power point tracing

Liu Xinyu,Yuan Shaoheng,Gu Bo,Chen Qiongxuan,Pu Xinyu,Zhang Jiangtao 한국물리학회 2022 Current Applied Physics Vol.36 No.-

The result of the structural, electronic and thermoelectric performance of monolayer Sb2S2Te, which is a brannew material, is calculated by using the method of full-potential linearized augmented plane-wave (FP-LAPW), and the exchange-correlation potential selected in this paper is generalized gradient approximation (GGA) scheme. There are no negative frequencies in the calculated phonon spectra, which demonstrates that dynamics of monolayer Sb2S2Te is stable in theory. The average value of lattice thermal conductivity (κl) is smaller than that of other thermoelectric (TE) materials, and monolayer Sb2S2Te has larger figure of merit (ZT) comparing with other well-known materials. According to the TE parameters (Seebeck coefficient S, electrical conductivity σ, electronic thermal conductivity κe and lattice thermal conductivity κl) of monolayer Sb2S2Te, an idealized model of thermoelectric generator (TEG) and a realistic model of maximum power point tracking (MPPT) are built. In addition, this paper studies the influence of different temperature zones, different temperature differences, cross sectional area, height and the number of P–N junction on output power and conversion efficiency of TEG. The results of physical calculation and simulation models show that the conversion efficiency of TEG of monolayer Sb2S2Te is larger than or close to that of other well-known materials, and the tracking accuracy of MPPT proposed in this paper is higher than or close to that of other researches.

Microstructures and Thermoelectric Properties of Spark Plasma Sintered In4Se3

( Young Soo Lim ),( Ja Young Cho ),( Jae Ki Lee ),( Soon Mok Choi ),( Kyoung Hun Kim ),( Won Seon Seo ),( Hyung Ho Park ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 ELECTRONIC MATERIALS LETTERS Vol.6 No.3

We report microstructures and thermoelectric properties of In4Se3 thermoelectric materials. In4Se3 powder was synthesized by conventional melting process in evacuated quartz ampoules and sintering of In4Se3 was performed by spark plasma method at various sintering temperature. The microstructure and density of the sintered body of In4Se3 were strongly dependent on the sintering temperature. Thermoelectric properties, such as electrical conductivity, Seebeck coefficient and thermal conductivity, were also characterized and the effects of the sintering condition on the thermoelectric properties were investigated.

Preparation of nanoparticle based thermoelectric composite materials

손재성 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

Highly efficient thermoelectric materials have attracted tremendous attention due to various technological applications such as power generation from waste heat and environmentally friendly refrigeration. Nano- and mesostructuring is widely used in thermoelectric (TE) materials. It introduces numerous interfaces and grain boundaries that scatter phonons and decrease thermal conductivity. Chemically synthesized nanoparticles have been recognized as the noble nano-scale building blocks for the preparation of bulk-scale nanostructured thermoelectric materials as well as studying the fundamental thermoelectric properties of nano-scale materials. For example, the nanostructured Bi2Te3 bulk materials prepared from colloidal Bi2Te3 nanoplates also exhibited very high electrical conductivity and low thermal conductivity, consequently enhancing ZT values higher than pure that of Bi2Te3 bulk. Furthermore, all-inorganic Bi NCs capped with Sb2Te3 ligands were used as an additive to BiSbTe ball-milled micro-particles. During heat treatment, NCs fill up the interfaces and voids between micro-particles and act as a “glue” joining grains in hot-pressed pellets or solution-processed thin films. The chemical design of the NC glue allowed for the selective enhancement or reduction of the majority carrier concentration near the grain boundaries, and thus resulted in doped or de-doped inter-faces in granular BiSbTe material. The pellets with engineered interfaces showed increased power factors and reduced thermal conductivities compared to the reference samples without NC glue. This resulted in enhanced ZT values well above 1.

원자층 증착법을 이용한 열전 소재 연구 동향

이승혁,박태주,김성근 한국분말재료학회 2022 한국분말재료학회지 (KPMI) Vol.29 No.1

Atomic layer deposition (ALD) is a promising technology for the uniform deposition of thin films. ALD is based on a self-limiting mechanism, which can effectively deposit thin films on the surfaces of powders of various sizes. Numerous studies are underway to improve the performance of thermoelectric materials by forming core-shell structures in which various materials are deposited on the powder surface using ALD. Thermoelectric materials are especially relevant as clean energy storage materials due to their ability to interconvert between thermal and electrical energy by the Seebeck and Peltier effects. Herein, we introduce a surface and interface modification strategy based on ALD to control the performance of thermoelectric materials. We also discuss the properties of the interface between various deposition materials and thermoelectric materials.