Bi2Te3热电材料研究现状

Bi2Te3热电材料是半导体材料,室温下具有良好的热电特性,能够实现热能和电能的相互转化,应用前景十分广阔。Bi2Te3热电材料的转换效率低是影响其应用的瓶颈之一,目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率上。综述了热电材料的种类、国内外关于Bi2Te3热电薄膜的制备方法和性能研究,对多种典型制备方法进行分析对比,探讨了影响Bi2Te3热电薄膜质量的因素及机制。结合Bi2Te3热电薄膜在温差发电和热电制冷方面的应用,如果微型热电制冷器实现与大功率LED芯片集成封装,那么芯片级低温散热问题有望解决。     

温差发电专利技术分析及发展预测

温差发电是一种基于热电材料的塞贝克效应发展起来的技术,具有结构简单、无运动部件、无噪声等优点。本文从专利视角出发,通过检索、统计和分析国内外相关文献,梳理了温差发电的专利技术发展脉络,并对未来发展趋势进行预测。     

自供能传感器能量采集技术的研究现状北大核心

归纳了国内外自供能微电源技术的研究现状,阐述了环境能量采集技术结构设计与能量转换机理。当前能量采集器主要依靠特殊功能材料完成能量转换,耦合方式包括：压电效应、磁致伸缩效应、摩擦发电效应、热释电效应、静电效应、光电效应等。能量来源包括：振动机械能、磁场能、摩擦能、温差能、风能、海洋能和太阳能等。能量采集器的结构形式有单一能量转换和复合能量转换等。为了提高能量采集装置的发电性能,研究重点是结构优化设计、换能材料改性、降低储能电路自损耗等。自供能微电源未来的发展趋势包括增强环境自适应能力、改进自供电能量转换效率、加快实用化步伐等。     

悬臂梁双晶压电片不同连接方式发电性能

为了更加有效提高双压电振动能量采集器的发电效率,以双晶压电片为研究对象,设计了一种可收集电动机机械振动能量的双压电振动能量采集器。探究了电动机不同转速下,双晶压电片不同连接方式的内阻和发电特性;分析了电动机在不同转速下,双晶压电片不同连接方式时双压电振动能量采集器输出电压和输出功率的特性。理论计算与实验结果进行对比,选择一种最优的双晶压电片连接方式。     

MEMS压电能量采集器的研究进展

压电材料可以将机械能转化为电能的特殊性质引起了基于压电材料的能量采集器的研究.概述了压电能量采集器收集能量的原理,分别介绍了压电能量采集器的悬臂梁型、隔膜型和桥型这三种常用结构以及其他结构,介绍了一种利用块状压电陶瓷制作压电悬臂梁的新型工艺.简述了线性拓频和非线性振动拓频两种悬臂梁型能量采集器的带宽优化方法.举例说明了...     

热电材料的研究进展

随着热电材料与薄膜制备技术和性能研究手段的发展,具有高热电性能的热电薄膜和低维结构受到人们关注。目前,国内外研究主要集中在如何提高热电材料的能量转换率等核心技术问题上。介绍了热电材料的理论背景、材料分类、制备手段和热电性质的表征,其中,制备手段及热电性质表征主要以Bi2Te3基热电材料展开论述。最后,对热电材料的发展和未来研究方向进行总结。     

微压电式振动能量采集器的研究进展

给出了微压电式振动能量采集器的基本工作原理和物理模型。按照压电单元结构类型的不同,将其分为单一的直线型悬臂梁、直线型悬臂梁阵列、L型悬臂梁和圆形压电膜,分别讨论了各种类型的微压电振动能量采集器的优缺点。详细介绍了国内外各研究小组研制的微压电式振动能量采集器的结构参数、性能及其应用现状,分析针对目前研究中存在的问题,指出如果能在分析建模、压电结构及压电材料优化方面取得实质性进展,微压电振动能量采集器作为新型供能设备在MEMS系统和低功耗无线传感网络中的应用将会具有更加诱人的前景。     

振动能量采集器能量管理电路的研究

研究了一种抗磁悬浮式振动能量采集器,首先结合理论对抗磁悬浮振动采集器的工作原理进行了详细讨论,之后提出了适用于本结构的6倍压整流电路并对其进行仿真优化,最后利用振动台测试其在5 Hz、0.5 gn的激励条件下的输出特性,6倍压电路输出能够点亮LED灯,当充电时间为20 s时,输出电压可达1.7 V。该抗磁悬浮式振动能量采集器有望给便携式微型电子供电。     

流体能量采集研究进展

主要介绍了流体能量的采集,即将采集到的能量转化为电能以实现传感器及低功耗电子器件的自供电.流体能量采集器能有效地解决能源短缺的问题,从而提高电子设备的适用性.分析了流体采集能量的原理,详细介绍了流体能量采集器的各种结构,针对提高流体能量采集器的环境适应能力和工作效能,分析了各种能量采集器的优缺点和能量采集特性,最后通过...     

MSMA振动能量采集器的设计与实现

采用智能材料磁控形状记忆合金(MSMA)将机械振动能量转换成电能为无线电子设备供电已备受关注。该文利用MSMA的维拉利效应(逆磁致伸缩效应)分析了MSMA振动能量采集器工作原理,计算并确定了振动能量采集系统的磁轭、线圈、保护系统、固定装置的尺寸和性能参数。利用ANSYS软件对系统进行了仿真,验证了各部分结构参数和材料选型的正确性。在此基础上,设计制作了MSMA振动能量采集器样机,搭建了MSMA振动能量采集器实验平台,进行了振动力激振实验,得到了在不同输入频率和应力大小条件下感应电压的输出曲线,实验和仿真结果表明,利用MSMA材料可将机械振动能量转化为电能,为振动能量收集利用提供了参考依据。     

基于参考辐射源标定的红外成像非均匀校正技术

持续外场工作环境下,红外系统成像的非均匀性会随工作时间、温度的改变而发生飘移,要维持非均匀性校正精度,定标动作需要定期重复,而标准黑体笨重不便于携带,使其不适用于现场定标应用。针对这一问题,介绍了一种基于参考辐射源进行红外图像校正的方法。该方法利用一个精确控温的小巧辐射源,可随时根据需要插入红外成像系统光路中进行非均匀性标定测试,实时修正硬件平台中存储的非均匀性校正参数,从而达到维持校正精度的目的。实验结果表明,所述的辐射源具有较高的稳定性,与环境温差在-10~10 K的范围内温度波动可以控制在0.04 K范围,使用该人工辐射源可以明显降低非均匀性随时间的恶化。     

Advanced Thermoelectric Materials for Flexible Cooling Application

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.     

制备工艺对新型热电材料制冷性能的影响

通过取点法得到了由Ingot法、BM法、S-MS法和Te-MS法制备的四种新型p型热电材料(Bi0.5Sb1.5)Te3的变物性参数拟合公式,分析了温度对不同方法制备的热电材料的影响,得到了热电材料无量纲优值与绝对温度的关系曲线.从热力学方面研究了制备工艺对基于新型热电材料的热电制冷器最大制冷系数的影响.结果表明:由Te-MS法制备的新型p型热电材料(Bi0.5Sb1.5)Te3具有最大的优值系数,基于该材料的热电制冷器最大制冷系数可达2.49,较其他三种方法制备的热电材料分别提升了 34.59％,37.57％和25.76％.     

基于Bi_2Te_3合金材料的热发电模块研究

为了提高Bi2Te3热电材料的性能,采用Bi2Te3纳米粉体前驱物快速熔炼烧结法,制备了在室温条件下具有温度敏感性的Bi2Te3合金材料,在425K时此材料的热电优值达到0.548。在此基础上,研制了热电模块,并对其性能进行了测试。结果表明,以该Bi2Te3合金材料制备的热发电模块具有良好的伏安特性和稳定的内阻,当热冷端温度分别为140和60℃时,模块的最大输出功率可达到0.39W,显现出潜在的应用前景。     

Reversible Room Temperature Brittle-Plastic Transition in Ag2Te0.6S0.4 Inorganic Thermoelectric Semiconductor

Inorganic semiconductors with superior plasticity are highly desired in current flexible electronics, which however are rarely discovered owing to their intrinsic covalent and ionic bonds. The Ag₂Te_0.6S_0.4 semiconductor with an amorphous phase has recently been reported to exhibit plastic deformability. In this study, the reversible brittle-plastic transition is found in this inorganic semiconductor, and the plasticity of the Ag₂Te_0.6S_0.4 sample is highly related to the phase structures. The Ag₂Te_0.6S_0.4 with a monoclinic phase exhibits a brittle behavior, while the one with cubic-crystalline/amorphous structure shows exceptional plasticity with a compressive strain of over 80%. Significantly, the reversible plastic-brittle transition in Ag₂Te_0.6S_0.4 inorganic semiconductor can be achieved by simple heat treatment. Besides the plasticity, the cubic-crystalline/amorphous Ag₂Te_0.6S_0.4 composites also possess good thermoelectric performance. This study uncovers the influence of phase structure on the mechanical properties of Ag₂Te_0.6S_0.4 and realizes the reversible brittle-plastic transition, facilitating its prospective application in flexible/wearable electronics.     

Micro- and Nano-Technology: A Critical Design Key in Advanced Thermoelectric Cooling Systems

Advanced thermoelectric (TE) cooling technologies are now receiving more research attention, to provide cooling in advanced vehicles and residential systems to assist in increasing overall system energy efficiency and reduce the impact of greenhouse gases from leakage by current R-134a systems. This work explores the systems-related impacts, barriers, and challenges of using micro-technology solutions integrated with advances in nano-scale thermoelectric materials in advanced TE cooling systems. Integrated system-level analyses that simultaneously account for thermal energy transport into and dissipation out of the TE device, environmental effects, temperature- dependent TE and thermo-physical properties, thermal losses, and thermal and electrical contact resistances are presented, to establish accurate optimum system designs using both p-type nanocrystalline-powder-based (NPB) Bi _x Sb_2−x Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems and conventional p-type Bi₂Te₃-Sb₂Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems. This work established the design trends and identified optimum design regimes and metrics for these types of systems that will minimize system mass, volume, and cost to maximize their commercialization potential in vehicular and residential applications. The relationships between important design metrics, such as coefficient of performance, specific cooling capacity, and cooling heat flux requirements, upper limits, and critical differences in these metrics in p-type NPB Bi _x Sb_2−x Te₃/ n-type Bi₂Te₃-Bi₂Se₃ TE systems and p-type Bi₂Te₃-Sb₂Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems, are explored and quantified. Finally, the work discusses the critical role that micro-technologies and nano-technologies can play in enabling miniature TE cooling systems in advanced vehicle and residential applications and gives some key relevant examples. Pacific Northwest National Laboratory—operated for the U.S. Department of Energy by Battelle Memorial Institute under contract DE-AC05-76RLO1830.     

Robust High Thermoelectric Harvesting Under a Self‐Humidifying Bilayer of Metal Organic Framework and Hydrogel Layer

Robust thermoelectric harvesting is explored from a proton‐doped mixed ionic conductive (PMIC) film under water‐harvesting metal organic framework (MOF) film coupled with hydrogel layer (MOF/HG). As a PMIC, highly doped poly(3,4‐ethylenedioxythiophene)s with poly(styrene sulfonate) (PEDOT:PSS) is prepared by precisely controlling the proton doping to afford a stable and high thermoelectric PMIC. Among the PMICs, the PEDOT:PSS film doped with 30 wt% of poly(styrene sulfonic acid) (PSSH) recorded a Seebeck coefficient of over 16.2 mV K^?1 and a thermal voltage of 81 mV for a temperature gradient (ΔT) of 5 K. The thermal charging on PMICs afforded high thermal voltage and current output, reproducibly, to show cumulative thermoelectric nature. Environmentally sustainable thermoelectric harvesting is achieved from a PMIC under a MOF/HG, prepared by water‐harvesting MOF‐801 coupled with a HG layer, to provide constant relative humidity of 90% and V_oc over 72 h at ambient condition.     

Experimental Characterization of Thermoelectric Modules and Comparison with Theoretical Models for Power Generation

The interest in thermoelectrics for power generation applications has dramatically increased over the past decade as a result of recent advancements in thermoelectric materials. Although measuring thermoelectric properties of materials has received significant attention, measuring thermoelectric module (TEM) power generation performance has received less attention. Characterizing TEMs is vital for validating module-level models used in optimizing TEM designs. Measurements of module performance can also be used for the optimal incorporation of TEMs into power generation systems. A TEM test apparatus has been developed and characterized to test current and future modules under a wide range of temperature and loading conditions. In addition to temperatures and electrical performance metrics, heat rates, and mechanical loading conditions are monitored. The developed technique extracts module parameters, which can be used for system-level design, to measure performance of advanced TEMs, and to validate theoretical models for module design optimization. Experimental results are compared with standard analytical TEM models and a newly developed model.