共查询到20条相似文献，搜索用时 15 毫秒
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Muhammad Muddasar Mohammad Ali Nasiri Andres Cantarero Clara Gómez Mario Culebras Maurice N. Collins 《Advanced functional materials》2024,34(12):2306427
Wood-based ionic conductive membranes have emerged as a new paradigm for low-grade thermal energy harvesting applications due to their unique andtailorable structures. Herein, a lignin-derivedionic conducting membrane with hierarchical aligned channels is synthesized viaa double network crosslinking approach. Their excellent thermal stability andsuperior swelling ratio allow their optimization as low-grade heat recovery technologies. Several vertically aligned nanoscaleconfinements are found in the synthesized membranes, contributing towardenhanced ionic diffusion. Among all the combinations, the membrane comprising69.2 wt.% of lignin and infiltrated with 0.5 m KOH exhibits anexceptional ionic figure of merit (ZTi) of 0.25, relatively higher ionic conductivity(51.5 mS cm‒1), lower thermal conductivity(0.195 W m‒1·K), and a remarkable ionic Seebeck coefficientof 5.71 mV K‒1 under the application of an axialtemperature gradient. A numerical model is also utilized to evaluate theveracity of experimental observations and to gain a better understanding of thefundamental mechanisms involved in attaining such values. These results displaythe potential of lignin-basedmembranes for future thermal energy harvesting applications and are a new facetin thermoelectric energy conversion which is certain to pave the way forfurther investigations on sustainable ionic conductive membranes. 相似文献
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Jiamin Ding Wenrui Zhao Wenlong Jin Chong-an Di Daoben Zhu 《Advanced functional materials》2021,31(20):2010695
Flexible cooling devices, which aim to fulfill the essential requirement of complex working environments and enable local heat dissipation, have become the cutting-edge area of refrigeration technology. Thermoelectric (TE) material represents a promising candidate for various flexible cooling applications, including wearable personal thermoregulation devices. With the increasing interest in the Peltier effect of conductive polymers and inorganic films on flexible substrates, flexible cooling devices have undergone rapid development. Herein, the fundamental mechanisms, basic parameters, and temperature measurement techniques for evaluating the cooling performance are summarized. Moreover, recent progress on TE materials, such as flexible inorganic and organic materials for Peltier cooling studies, is reviewed. More importantly, insights are provided into the key strategies for high-performance Peltier devices. The final part details the existing challenges and perspectives on flexible TE cooling to inspire additional research interests toward the advancement of refrigeration technology. 相似文献
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《Advanced Electronic Materials》2017,3(4)
Thermoelectric materials enable conversion of heat to electrical energy. The performance of electronic thermoelectric materials is typically evaluated using a figure of merit ZT = σα 2T /λ, where σ is the conductivity, α is the so‐called Seebeck coefficient, and λ is the thermal conductivity. However, it has been unclear how to best evaluate the performance of ionic thermoelectric materials, like ionic solids and electrolytes. These systems cannot be directly used in a traditional thermoelectric generator, because they are based on ions that cannot pass the interface between the thermoelectric material and external metal electrodes. Instead, energy can be harvested from the ionic thermoelectric effect by charging a supercapacitor. In this study, the authors investigate the ionic thermoelectric properties at varied relative humidity for the polyelectrolyte polystyrene sulfonate sodium and correlate these properties with the charging efficiency when used in an ionic thermoelectric supercapacitor (ITESC). In analogy with electronic thermoelectric generators, the results show that the charging efficiency of the ITESC can be quantitatively related to the figure of merit ZTi = σiαi 2T /λ. This means that the performance of ionic thermoelectric materials can also be compared and predicted based on the ZT , which will be highly valuable in the design of high‐performance ITESCs. 相似文献
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Saeed Mardi Dan Zhao Nara Kim Ioannis Petsagkourakis Klas Tybrandt Andrea Reale Xavier Crispin 《Advanced Electronic Materials》2021,7(12):2100506
Organic-based energy harvesting devices can contribute to a sustainable solution for the transition to renewable energy sources. The concept of ionic thermoelectrics (iTE) has been recently proposed and motivated by the high values of thermo-voltage in electrolytes. So far, most research has focused on developing new electrolytes with high Seebeck coefficient. Despite the major role of the electrode materials in supercapacitors and batteries, the effect of various electrodes on energy harvesting in iTE devices has not been widely studied. In this work, the conducting polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is investigated as the functional electrodes in iTE supercapacitors. Through investigating the thermo-voltage of iTEs of the same electrolyte with varying composition of PEDOT electrodes, it is identified that the different PSS content greatly affects the overall thermo-induced voltage coefficient, Seff (i.e., effective thermopower). The permselective polyanion in the electrode causes cation concentration differences at the electrode/electrolyte interface and contributes to an interfacial potential drop that is temperature dependent. As a result, the overall thermo-voltage of the device possesses both an interfacial and a bulk contribution. The findings extend the fundamental understanding of iTE effect with functional electrodes, which could lead a new direction to enhance the heat-to-electricity conversion. 相似文献
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A sensitive apparatus for determining the conductivity and thermoelectric power of conducting polymer films at temperatures between 150 and 450 K is described. Brittle polyparaphenylene films doped by ion implantation with either alkali (caesium, sodium) or halogen (iodine) ions are studied by this method. Analysis of the temperature dependence of both conductivity and thermopower shows that the doping process of this conjugated polymer is efficient only when low parameters of implantation are selected and appears around room temperature. At higher temperatures the thermopower exhibits an anomalous evolution that we attribute to oxygen migration. © 1997 John Wiley & Sons, Ltd. 相似文献
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Yuanzhi Ma Jonathan M. Goodwill Dasheng Li David A. Cullen Jonathan D. Poplawsky Karren L. More James A. Bain Marek Skowronski 《Advanced Electronic Materials》2019,5(7)
Oxide‐based resistive‐switching devices hold promise for solid‐state memory technology. Information encoding is accomplished by electrically switching the device between two nonvolatile states with low and high resistance states (LRS/HRS). It is generally accepted that the change between these states is due to the motion of oxygen vacancies forming a continuous (LRS) or gapped (HRS) filament between the electrodes. Direct assessments of filaments are rare due to their small size and the difficulty of locating the filament. Electron microscopy experiments reveal the filament structure and chemistry in TaO2.0 ± 0.2‐based 150 × 150 nm2 devices with cross‐sectional geometry after forming with power dissipation lower than 1 mW. The filaments appear to be roughly hourglass‐shaped with a diameter of less than 10 nm and are composed of Ta‐rich and O‐poor mostly amorphous material with local compositions as Ta‐rich as TaO0.4. The as‐formed HRS has a gap up to 10 nm wide located next to the anode and composed of nearly stoichiometric TaO2.5. The tantalum and oxygen distribution is consistent with filaments formed by the motion of both Ta and O driven by temperature gradients (Soret effect) and an electric field. This interpretation points towards a new compact model of resistive‐switching devices. 相似文献
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热电能量采集器是一种基于塞贝克效应,利用温差将热能直接转化成电能的温差发电装置.由于其体积小、重量轻、寿命长、无机械运动部件、绿色环保等优点,微型热电能量采集器(MTEG)已经引起了国内外的广泛关注.综述了微型热电能量采集器在国内外的研究进展,介绍了温差发电的工作原理,从热电材料和器件结构两方面重点探讨了微型热电能量采集器的研究现状.对微型热电能量采集器未来的发展方向进行了分析和预测,认为积极寻找具有高优值系数的热电材料制备易于加工和集成的高性能的微型热电能量采集器是未来研究工作的目标.微型热电能量采集器有广阔的应用前景. 相似文献
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Fengjiao Zhang Yaping Zang Dazhen Huang Chong‐an Di Xike Gao Henning Sirringhaus Daoben Zhu 《Advanced functional materials》2015,25(20):3004-3012
Organic thermoelectric materials, which can transform heat flow into electricity, have great potential for flexible, ultra‐low‐cost and large‐area thermoelectric applications. Despite rapid developments of organic thermoelectric materials, exploration and investigation of promising organic thermoelectric semiconductors still remain as a challenge. Here, the thermoelectric properties of several p‐ and n‐type organic semiconductors are investigated and studied, in particular, how the electric field modulations of the Seebeck coefficient in organic field‐effect transistors (OFETs) compare with the Seebeck coefficient in chemically doped films. The extracted relationship between the Seebeck coefficient (S) and electrical conductivity (σ) from the field‐effect transistor (FET) geometry is in good agreement with that of chemically doped films, enabling the investigation of the trade‐off relationship among σ, S, carrier concentration, and charging level. The results make OFETs an effective candidate for the thermoelectric studies of organic semiconductors. 相似文献
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采用有限差分法对脉冲电压驱动下的瞬态热电效应及其动态特性过程进行了理论分析,探索了非稳态工况下帕尔帖效应、焦耳热效应与傅里叶导热效应之间的耦合关系及其关键制约因素对制冷性能的影响规律,进而探讨了脉冲驱动强化热电制冷性能的作用机理。分析结果得到,在合理电压域值内采用主动控制方法,对热电模块周期性施加数倍于稳态工况理想电压的脉冲突变电压,有益于充分利用帕尔贴制冷效应而推迟出现以焦耳热和傅里叶热耗散形式为主的内部热积聚对热电模块冷端引起的负效应,并能瞬态实现冷端面的制冷强化作用和最大程度实现输入电能的有效转换。该结论不仅为进一步提出脉冲驱动模式的优化控制策略提供了理论依据,也为瞬态热电制冷效应的应用开辟了一条新思路。 相似文献
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The Seebeck coefficient is determined from silicon microchannel plates (Si MCPs) prepared by photo-assisted electrochemical etching at room temperature (25 ℃). The coefficient of the sample with a pore size of 5 × 5 μm2, spacing of 1 μm and thickness of about 150 μm is -852 μV/K along the edge of the square pore. After doping with boron and phosphorus, the Seebeck coefficient diminishes to 256 μV/K and -117 μV/K along the edge of the square pore, whereas the electrical resistivity values are 7.5 × 10-3 Ω·cm and 1.9 × 10-3 Ω·cm, respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon. Based on the boron and phosphorus doped samples, a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect. When a proper current passes through the device, the Peltier effect is evidently observed. Based on the experimental data and the theoretical calculation, the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/(m·K), respectively. 相似文献
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Takuma Itoh Yusuke Kozuka Takamasa Hirai Ken-ichi Uchida 《Advanced functional materials》2024,34(49):2409557
Transverse thermoelectric conversion phenomena including the anomalous Ettingshausen effect (AEE) and anomalous Nernst effect (ANE) in magnetic materials are actively investigated to realize versatile cooling and energy harvesting technologies. However, further improvement of the thermoelectric performance of AEE and ANE is still required, and most research efforts have focused on material exploration. Here, a new approach to improve the transverse thermoelectric conversion performance through interface engineering is reported by focusing on the transverse thermoelectric phenomena that output heat currents. A longitudinal charge current in a ferromagnetic metal Ni/nonmagnetic insulator Bi2WO6 hybrid-structure induces a larger transverse heat current than that of AEE in a Ni single-layer. It is indicated that the enhancement of the transverse thermoelectric conversion is due to the generation of a heat current concomitant with a spin current induced at the Ni/Bi2WO6 interface. This finding demonstrates that the interface of a magnetic metal/nonmagnetic insulator has a potential to improve the transverse thermoelectric performance, extending the applicability of nonmagnetic insulators to the field of spin caloritronics and thermoelectrics. 相似文献
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Field effect and thermoelectric power measurements have been made as a function of temperature on a series of As-doped amorphous
silicon samples prepared by glow discharge decomposition of silane. At lower temperatures field effect screening is by localized
states at the Fermi level, whereas at higher temperatures it is by mobile carriers in extended states. The density of localized
states at the Fermi level increases as the As density increases, at least partially due to the creation of localized states
by As donors. The density of surface states is less than or equal to 5 × 1011 cm−2 eV−1. Electrical transport is interpreted in a two-channel model, involving transport both in extended states and in a band of
localized states lying above the Fermi level, the center of which shifts toward the extended states as the doping concentration
increases.
Supported by the National Science Foundation. 相似文献
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The Seebeck coefficient is determined from silicon microchannel plates（Si MCPs） prepared by photoassisted electrochemical etching at room temperature（25℃）.The coefficient of the sample with a pore size of 5×5μm2,spacing of 1μm and thickness of about 150μm is -852μV/K.along the edge of the square pore.After doping with boron and phosphorus,the Seebeck coefficient diminishes to 256μV/K and -117μV/K along the edge of the square pore,whereas the electrical resistivity values are 7.5×10-3Ω·cm and 1.9×10-3Ω·cm,respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon.Based on the boron and phosphorus doped samples,a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect.When a proper current passes through the device,the Peltier effect is evidently observed.Based on the experimental data and the theoretical calculation,the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/（m·K）, respectively. 相似文献
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Dandan Li Huaizhou Zhao Shanming Li Beipei Wei Jing Shuai Chenglong Shi Xuekui Xi Peijie Sun Sheng Meng Lin Gu Zhifeng Ren Xiaolong Chen 《Advanced functional materials》2015,25(41):6478-6488
Thermoelectric devices can directly convert thermal energy to electricity or vice versa with the efficiency being determined by the materials’ dimensionless figure of merit (ZT). Since the revival of interests in the last decades, substantial achievements have been reached in search of high‐performance thermoelectric materials, especially in the high temperature regime. In the near‐room‐temperature regime, MgAgSb‐based materials are recently obtained with ZT ≈ 0.9 at 300 K and ≈1.4 at 525 K, as well as a record high energy conversion efficiency of 8.5%. However, the underlying mechanism responsible for the performance in this family of materials has been poorly understood. Here, based on structure refinements, scanning transmission electron microscopy (STEM), NMR experiments, and density function theory (DFT) calculations, unique silver and magnesium ion migrations in α‐MgAg0.97Sb0.99 are disclosed. It is revealed that the local atomic disorders induced by concurrent ion migrations are the major origin of the low thermal conductivity and play an important role in the good ZT in MgAgSb‐based materials. 相似文献
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针对小型半导体温差(TEG)发电器中接触热阻和接触电阻的影响进行了分析研究.结果表明,接触热阻和接触电阻只在2mm以内的电偶臂长度内有明显影响;在电偶臂长度小于1mm时,输出功率和热电效率均有一个急剧上升的变化阶段;当长度超过5mm后,输出功率和热电效率均趋于定值;在冷热端温度分别为283和383K,Z=0.0024K-1、电偶臂长为2mm、接触热阻比0.2和接触电阻比0.1条件下,热电功率约为4mW/mm2,热电效率约为3.5%,而理想无接触热阻和电阻的热电效率约为4.2%.由此可知,半导体温差发电器中接触热阻和接触电阻的影响不可忽视. 相似文献
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飞秒激光泵浦光电导天线、磁性异质结构、电光晶体、空气等会产生太赫兹脉冲,其产生原理主要基于飞秒激发下载流子、电极化的瞬态变化等非热效应。与此同时,飞秒激光泵浦物质不可避免地会产生超快热效应。近年来,基于超快热电效应以及与自旋相关的超快自旋热电子学效应产生太赫兹波获得越来越多的关注。本文详细介绍了利用塞贝克效应/能斯特效应这两种热电效应,以及自旋塞贝克效应/反常能斯特效应这两种自旋热电子学效应产生太赫兹波的研究进展。超快热电效应及超快自旋热电子学效应已在太赫兹产生方面展现出巨大潜力,有望推动太赫兹源及相关技术的发展。 相似文献
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Hassan Elhadidy Jan Franc Eduard Belas Pavel Hlídek Pavel Moravec Roman Grill Pavel Hoschl 《Journal of Electronic Materials》2008,37(9):1219-1224
Thermoelectric effect spectroscopy and photoluminescence techniques were used to study the defect levels in samples from three
crystals of CdTe:In grown by the vertical gradient freeze method. The main goal of the investigation was to study defects,
which strongly trap charge carriers or act as recombination centers in order to eliminate them from the technological process.
The main difference among detecting and non-detecting samples was the absence of electron traps with a very high capture cross-section
and energy 0.6 eV to 0.7 eV, which act as lifetime killers even at low concentrations. Recently published ab initio calculations show a complex of Te antisite and Cd vacancy within this energy range. 相似文献