Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics
Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics
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DOI：
10.1126/science.aaa4166
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发表时间：
2015-04-03
期刊：
影响因子：
56.9
通讯作者：
Kim, Sung Wng
中科院分区：
文献类型：
--
作者：
Kim, Sang Il;Lee, Kyu Hyoung;Kim, Sung Wng
热电技术的广泛使用受到块体合金相对较低的转换效率的限制，这是根据无因次优值系数(ZT)进行评估的。通过晶界和点缺陷散射降低晶格导热系数，可以提高大块合金的热导，降低晶格的热导率。在Bi0.5Sb1.5Te3(Bi0.5Sb1.5Te3)中，通过液相压实在低能晶界形成致密的位错阵列，有效地散射了中频声子，导致了显著降低的晶格热导率。全光谱声子散射和最小载流子散射显著地提高了ZT，在320Kelvin(K)下，ZT为1.86+/-0.15。此外，热电致冷器证实了其性能，最大温差为81K，远远高于目前商用的Peltier制冷装置。
The widespread use of thermoelectric technology is constrained by a relatively low conversion efficiency of the bulk alloys, which is evaluated in terms of a dimensionless figure of merit (zT). The zT of bulk alloys can be improved by reducing lattice thermal conductivity through grain boundary and point-defect scattering, which target low-and high-frequency phonons. Dense dislocation arrays formed at low-energy grain boundaries by liquid-phase compaction in Bi0.5Sb1.5Te3 (bismuth antimony telluride) effectively scatter midfrequency phonons, leading to a substantially lower lattice thermal conductivity. Full-spectrum phonon scattering with minimal charge-carrier scattering dramatically improved the zT to 1.86 +/- 0.15 at 320 kelvin (K). Further, a thermoelectric cooler confirmed the performance with a maximum temperature difference of 81 K, which is much higher than current commercial Peltier cooling devices.