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1.
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co20v thin films prepared by pulsed laser deposition on LaA1Oa (001). Both the electric resistivity p and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m. cm and 202 V/K at 980 K, resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples. A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature. The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application has high temperature thin film thermoelectric devices,  相似文献   
2.
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co2Oy thin films prepared by pulsed laser deposition on LaAlO3(001).Both the electric resistivity ρ and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m·Ω· cm and 202 μV/K at 980 K,resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples.A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature.The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application in high temperature thin film thermoelectric devices.  相似文献   
3.
负梯度闭孔泡沫金属的力学性能分析   总被引:1,自引:0,他引:1  
运用三维Voronoi技术生成闭孔梯度泡沫模型,结合有限元分析方法模拟负梯度闭孔泡沫金属在不同冲击速度下的力学行为.结果表明,随着冲击速度的提高,得到了与均匀泡沫一样的三种变形模式:准静态模式,过渡模式和冲击模式.通过对名义应力应变曲线和变形模式的研究,提出了一种新的定义局部密实化应变的方法,并研究了相对密度和密度梯度对它的影响.分别建立了相对密度和密度梯度与冲击速度的变形模式图.通过引入密实化因子,确定了三种变形模式对应的临界冲击速度.最后讨论了不同冲击速度下,密度梯度大小对泡沫材料能量吸收能力的影响.结果表明,在高速冲击的变形初期,密度梯度的绝对值越大,泡沫材料的能量吸收能力越强.  相似文献   
4.
刘冉  高琳洁  李龙江  翟胜军  王江龙  傅广生  王淑芳 《物理学报》2015,64(21):218101-218101
以CaCO3作为Ca2+源, 利用传统固相烧结法制备了Cd1-xCaxO (x=0, 0.01, 0.03, 0.05) 多晶块体样品并研究了Ca2+掺杂对CdO高温热电性能的影响. CaCO3的掺入会导致CdO多晶载流子浓度降低, 使Cd1-xCaxO的电阻率ρ和塞贝克系数的绝对值|S|增大、电子热导率κe减小. 同时, 在CdO中掺入CaCO3会引入点缺陷和气孔并可抑制CdO晶粒长大、晶界增多, 从而增加了对声子的散射, 使样品的声子热导率κp减小. 由于总热导率的大幅降低, Cd0.99Ca0.01O多晶样品在1000 K时的热电优值ZT可达0.42, 比本征CdO提高了约27%, 为迄今n型氧化物热电材料报道的最好结果之一.  相似文献   
5.
董国义  李龙江  吕青  王淑芳  戴守愚  王江龙  傅光生 《物理学报》2014,63(17):178102-178102
利用传统固相烧结法制备了Cd1-xLuxO(x=0%,0.1%,0.5%,0.75%,1.0%,1.25%,1.5%,2%)陶瓷样品并研究了Lu3+掺杂对其电、热输运性能的影响.随着Lu3+掺杂浓度的增大,Cd1-xLuxO样品的室温载流子浓度持续增大而其迁移率表现出先增大后减小的趋势.在300—1000 K测试温度区间内,Cd1-xLuxO的电导率表现出金属电导行为且其电导率和热导率均随着Lu3+掺杂浓度的增大而升高;塞贝克系数在整个测试区间内均为负值,其随温度和载流子浓度的变化关系可用自由电子模型描述.  相似文献   
6.
Thermoelectric(TE)materials have been considered as a strong candidate for recovering the waste heat from industry and vehicles due to the ability to convert heat directly into electricity.Recently,multinary diamond-like chalcogenides(MDLCs),such as Cu In Te_2,Cu_2Sn Se_3,Cu_3Sb Se_4,Cu_2ZnSnSe_4,etc.,are eco-friendly Pb-free TE materials with relatively large Seebeck coefficient and low thermal conductivity and have aroused intensive research as a popular theme in the TE field.In this review,we summarize the TE performance and device development of MDLCs.The features of crystalline and electronic structure are first analyzed,and then the strategies that have emerged to enhance the TE figure of merits of these materials are illustrated in detail.The final part of this review describes the advance in TE device research for MDLCs.In the outlook,the challenges and future directions are also discussed to promote the further development of MDLCs TE materials.  相似文献   
7.
Three Bi2Sr2Co2Oy thin films with different microstructures have been prepared by chemical solution deposition on LaAlO 3(001) through varying the annealing temperature.With the decrease in the annealing temperature,both the size and c-axis alignment degree of grains in the film decrease as well,leading to an increase in the film resistivity.In addition,the decrease in the annealing temperature also results in a slight increase in the Seebeck coefficient due to the enhanced energy filtering effect of the small-grain film.The nanostructured Bi2Sr2Co2Oy film with an average grain size of about 100 nm shows a power factor comparable to that of films with larger grains.Since the thermal conductivity of the nanostructured films can be depressed due to the enhanced phonon scattering by grain boundary,a higher figure of merit is expected in Bi2Sr2Co2Oy thin film with grains in nanometer size.  相似文献   
8.
A Bi2Sr2Co2Oy/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi2Sr2Co2Oy film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties are studied in a wide temperature range from 20 K to 300 K. The transport mechanism under the forward bias can be attributed to a trap- filled space-charge-limited current conduction mechanism. Under the irradiation of a 532-nm continuous wave laser, a clear photovoltaic effect is observed and the magnitude ofphotovoltage increases as the temperature decreases, The results demonstrate the potential application of a Bi2SrzCo2Oy-based heterojunction in the photoelectronic devices.  相似文献   
9.
王江龙  葛志启  李慧玲  刘洪飞  于威 《物理学报》2011,60(4):47107-047107
采用基于密度泛函理论的投影平面波方法,对后钙钛矿结构(Ppv)的CaRhO3的电子结构和磁学性质进行了研究.广义梯度(GGA)近似下的计算表明,Ppv-CaRhO3的基态为铁磁性半金属,Rh4+离子的磁矩大小为0.57μB,具有低自旋态构型;而考虑在位库仑作用修正的GGA+U计算,得到了与实验结果相符的反铁磁绝缘体基态,表明后钙钛矿结构中4d电子之间的关联效应对体 关键词: 电子结构 磁学性质 金属绝缘体转变  相似文献   
10.
利用脉冲激光沉积技术在c-Al2O3单晶基片上制备了Bi2Sr2Co2Oy热电薄膜并研究了沉积温度和氧压对薄膜晶体结构及电输运性能的影响.在最佳沉积条件下制备的单相、c轴取向的Bi2Sr2Co2Oy薄膜的室温电阻率ρ和塞贝克系数S分别为2.9mΩ/cm和110μupV/K,其功率因子S2/ρ好于在单晶样品上得到的值.此外,该薄膜在低温下表现出较强的负磁阻效应,在2K,9T时达到了40%.  相似文献   
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