复合与掺杂对Te、Se基热电材料性能的影响
发布时间：2019-05-10 08:13
【摘要】：热电材料可将热能与电能进行直接转换,未来在废热发电和热电制冷有广阔应用前景。热电材料目前的焦点是如何提高其热电优值ZT。本论文以BST和SnSe这两种含化合物为研究对象,通过对材料掺杂及引入纳米复合相等措施来探索提高其ZT值。论文的研究结果及创新点如下:(1)我们研究了 PbSe/BST复合体系的热电性能。结果表明:当在BST基体中引入PbSe纳米粒子时,PbSe纳米颗粒附近会形成界面势垒,因此抑制了少数载流子的输运,实现了增强塞贝克系数和降低双极效应来降低热导率,在此过程中我们提出了 "载流子散射工程"。因此,在复合了 0.2 vol.%的PbSe纳米颗粒的BST样品中,获得最大ZT = 1.56(400K),在300K至500K的温度范围内的平均ZTave达到1.44,相应地,在冷端为300K和热端为500K时实现了热电转换效率约10%。(2)我们研究了 Na掺杂对多晶SnSe热电性能的影响。结果表明:Na掺杂SnSe的电导率提高了约两个数量级,这可归因于Na原子替代了 Sn产生了大量的载流子(空穴);从而大幅提高了样品的功率因子。通过在SnSe中掺Na,在873K时我们得到了最大的ZT=1.2,比纯SnSe(ZT = 0.68)高出76%。(3)我们研究了 PbSe/Na_(0.003)Sn_(0.997)Se 和 PbTe/Na_(0.003)Sn_(0.997)Se 样品热电性能。样品的热导率大幅下降,这可归因于引入了第二相引起了很强的声子散射。在773K 时,获得了 ZT 值～1.3(f(PbSe)/Na_(0.003)Sn_(0.997)Se(f=0.5 vol.%)。
[Abstract]:Thermoelectric materials can convert heat energy and electric energy directly, and have broad application prospects in waste heat power generation and thermoelectric refrigeration in the future. The current focus of thermoelectric materials is how to improve their thermoelectric optimal value ZT. In this paper, BST and SnSe are taken as the research objects to explore how to improve the ZT value by doping the materials and introducing nanocomposite equality measures. The research results and innovations of this paper are as follows: (1) We studied the thermoelectric properties of PbSe/BST composite system. The results show that when PbSe nanoparticles are introduced into BST matrix, the interface barrier is formed near the PbSe nanoparticles, so the transport of minority carriers is suppressed, and the Seebeck coefficient is enhanced and the bipolar effect is reduced to reduce the thermal conductivity. In this process, we propose "carrier scattering engineering". Therefore, in the BST sample with 0.2 vol.% PbSe nanoparticles, the maximum ZT = 1.56 (400K) is obtained, and the average ZTave reaches 1.44 in the temperature range of 300K to 500K. The thermoelectric conversion efficiency is about 10% when the cold end is 300K and the hot end is 500K. (2) the effect of Na doping on the thermoelectric properties of polycrystalline SnSe is studied. The results show that the conductivity of Na doped SnSe is increased by about two orders of magnitude, which can be attributed to the large number of carriers (holes) produced by Na atoms instead of Sn, thus greatly increasing the power factor of the samples. By adding Na, to SnSe at 873k, we get the largest ZT=1.2,. The thermoelectric properties of PbSe/Na_ (0.003) Sn_ (0.997) Se and PbTe/Na_ (0.003) Sn_ (0.997) Se samples were studied. (3) the thermoelectric properties of PbSe/Na_ (0.003) Sn_ (0.997) Se and PbTe/Na_ (0.003) Sn_ (0.997) Se samples were studied. The thermal conductivity of the sample decreases greatly, which can be attributed to the strong phonon scattering caused by the introduction of the second phase. At 773k, the ZT value of ~ 1.3 (f (PbSe) / Na_ (0.003) Sn_ (0.997) Se (f 鈮，
本文编号：2473490
[Abstract]:Thermoelectric materials can convert heat energy and electric energy directly, and have broad application prospects in waste heat power generation and thermoelectric refrigeration in the future. The current focus of thermoelectric materials is how to improve their thermoelectric optimal value ZT. In this paper, BST and SnSe are taken as the research objects to explore how to improve the ZT value by doping the materials and introducing nanocomposite equality measures. The research results and innovations of this paper are as follows: (1) We studied the thermoelectric properties of PbSe/BST composite system. The results show that when PbSe nanoparticles are introduced into BST matrix, the interface barrier is formed near the PbSe nanoparticles, so the transport of minority carriers is suppressed, and the Seebeck coefficient is enhanced and the bipolar effect is reduced to reduce the thermal conductivity. In this process, we propose "carrier scattering engineering". Therefore, in the BST sample with 0.2 vol.% PbSe nanoparticles, the maximum ZT = 1.56 (400K) is obtained, and the average ZTave reaches 1.44 in the temperature range of 300K to 500K. The thermoelectric conversion efficiency is about 10% when the cold end is 300K and the hot end is 500K. (2) the effect of Na doping on the thermoelectric properties of polycrystalline SnSe is studied. The results show that the conductivity of Na doped SnSe is increased by about two orders of magnitude, which can be attributed to the large number of carriers (holes) produced by Na atoms instead of Sn, thus greatly increasing the power factor of the samples. By adding Na, to SnSe at 873k, we get the largest ZT=1.2,. The thermoelectric properties of PbSe/Na_ (0.003) Sn_ (0.997) Se and PbTe/Na_ (0.003) Sn_ (0.997) Se samples were studied. (3) the thermoelectric properties of PbSe/Na_ (0.003) Sn_ (0.997) Se and PbTe/Na_ (0.003) Sn_ (0.997) Se samples were studied. The thermal conductivity of the sample decreases greatly, which can be attributed to the strong phonon scattering caused by the introduction of the second phase. At 773k, the ZT value of ~ 1.3 (f (PbSe) / Na_ (0.003) Sn_ (0.997) Se (f 鈮，
本文编号：2473490
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2473490.html
