Seebeck Coefficient Metrology: Do Contemporary Protocols Measure Up?
Seebeck Coefficient Metrology: Do Contemporary Protocols Measure Up?
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塞贝克系数计量：当代协议是否符合标准？
DOI：
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发表时间：
2015
影响因子：
2.1
通讯作者：
Martin L. Green
中科院分区：
文献类型：
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作者：
Joshua Martin;W. Wong;Martin L. Green
由于仪器和测量协议的多样性，塞贝克系数的比较测量具有挑战性。通过实施标准化测量协议和使用标准参考材料 (SRM®)，例如最近获得美国国家标准技术研究院 (NIST) SRM® 3451“低温塞贝克系数标准 (10–390 K)”认证，研究人员可以可靠地分析和比较实验室内和实验室间的数据，从而加速更高效热电材料和器件的开发。我们对常用的塞贝克系数测量实践进行了比较概述。首先，我们研究了电位和温度的异步时间和空间测量的影响。时间异步性引入约 10% 数量级的绝对塞贝克系数误差，而空间异步性引入百分之几数量级的误差。其次，我们检查测量探头和样品之间热接触不良的影响。这在高温下尤其重要，其中测量表面温度的流行模式是通过压力接触来促进的。每个主题将包括使用不同测量技术和不同探头布置测量的数据的比较。我们证明了探头布置是高精度的主要限制，其中 2 探头布置测量的塞贝克系数和 4 探头布置测量的塞贝克系数随着温度的升高而发散，在 900 K 时接近 ≈14%。利用这些分析，我们提供推荐的测量协议来指导热电材料界的成员进行更准确的测量和评估更全面的不确定性限制。
Comparative measurements of the Seebeck coefficient are challenging due to the diversity of instrumentation and measurement protocols. With the implementation of standardized measurement protocols and the use of Standard Reference Materials (SRMs®), for example, the recently certified National Institute of Standards and Technology (NIST) SRM® 3451 ‘‘Low Temperature Seebeck Coefficient Standard (10–390 K)’’, researchers can reliably analyze and compare data, both intra- and inter-laboratory, thereby accelerating the development of more efficient thermoelectric materials and devices. We present a comparative overview of commonly adopted Seebeck coefficient measurement practices. First, we examine the influence of asynchronous temporal and spatial measurement of electric potential and temperature. Temporal asynchronicity introduces error in the absolute Seebeck coefficient of the order of ≈10%, whereas spatial asynchronicity introduces error of the order of a few percent. Second, we examine the influence of poor thermal contact between the measurement probes and the sample. This is especially critical at high temperature, wherein the prevalent mode of measuring surface temperature is facilitated by pressure contact. Each topic will include the comparison of data measured using different measurement techniques and using different probe arrangements. We demonstrate that the probe arrangement is the primary limit to high accuracy, wherein the Seebeck coefficients measured by the 2-probe arrangement and those measured by the 4-probe arrangement diverge with the increase in temperature, approaching ≈14% at 900 K. Using these analyses, we provide recommended measurement protocols to guide members of the thermoelectric materials community in performing more accurate measurements and in evaluating more comprehensive uncertainty limits.