Low‐Temperature, Template‐Free Synthesis of Single‐Crystal Bismuth Telluride Nanorods
Low‐Temperature, Template‐Free Synthesis of Single‐Crystal Bismuth Telluride Nanorods
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DOI：
10.1002/adma.200501339
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发表时间：
2006-02
影响因子：
29.4
通讯作者：
A. Purkayastha;Fabio Lupo;Seongyul Kim;T. Borca-Tasciuc;G. Ramanath
中科院分区：
文献类型：
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作者：
A. Purkayastha;Fabio Lupo;Seongyul Kim;T. Borca-Tasciuc;G. Ramanath
高效率的固态热电能量转换需要具有大的热电优值（ZT）的材料，定义为[1] r S 2 T / j，其中S是塞贝克系数，r是电导率，j是热导率，T是绝对温度。用于热电冷却应用的现有技术材料是基于Bi 2 Te 3 /Sb 2 Te 3和Bi 2 Te 3 /Bi 2 Se 3的合金，ZT为1，而ZT为4必须超过竞争技术。[2]纳米结构化这些热电材料最近已经成为一种成功的策略，以获得ZT的因子增强，[3-6]分别由于电荷和热载体的量子和经典尺寸效应。[2，5]电荷载流子的量子限制被认为由于费米能级处的态密度增加而提高了塞贝克系数S和电导率r。[7-9] .此外，热载体的强烈边界和界面散射降低了热导率，[2，5，10 -13]在Bi 2 Te 3 /Sb 2 Te 3纳米层超晶格[3]中举例说明，其表现出ZT ≥ 2.3。随着纳米结构的维数降低，由于存在更强的量子限制和热导率降低效应，预期ZT进一步增加。亚纳米直径的碲化铋纳米棒预计产生高达14的ZT值，这比二维（2D）量子威尔斯的预测值高出近三倍。[14-16]然而，如果直径> 5 nm，
High-efficiency, solid-state thermoelectric energy conversion requires materials with a large thermoelectric figure of merit ( ZT ), defined as [1] r S 2 T / j , in which S is the Seebeck coefficient, r the electrical conductivity, j the thermal conductivity, and T the absolute temperature. The state of the art materials for thermoelectric cooling applications are alloys based on Bi 2 Te 3 /Sb 2 Te 3 and Bi 2 Te 3 /Bi 2 Se 3 with ZT ∼ 1, while a value of ZT ∼ 4 is necessary to surpass competing technologies. [2] Nanostructuring these thermoelectric materials has recently emerged as a successful strategy to gain factorial enhancements in ZT , [3–6] owing to quantum and classical size effects of the charge and heat carriers, respectively. [2,5] Quantum confinement of the charge carriers is believed to enhance the Seebeck coefficient S and electrical conductivity r owing to an increased density of states at the Fermi level. [7–9] . More-over, intense boundary and interface scattering of heat carriers decreases thermal conductivity, [2,5,10–13] exemplified in the Bi 2 Te 3 /Sb 2 Te 3 nanolayer superlattices [3] exhibiting ZT ∼ 2.3. Further increases in ZT are expected due to the presence of stronger quantum confinement and thermal conductivity reduction effects as the dimensionality of the nanostructures is decreased. Sub-nanometer-diameter nanorods of bismuth telluride are predicted to yield ZT values as high as 14, which is nearly threefold higher than the value predicted for two-dimensional (2D) quantum wells. [14–16] However, if the diameter is > 5 nm the electrical transport