Investigation of the effect of microstructural changes on thermal transport in semicrystalline polymer semiconductors
Investigation of the effect of microstructural changes on thermal transport in semicrystalline polymer semiconductors
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DOI：
10.1063/1.5111023
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发表时间：
2019-08-01
期刊：
影响因子：
6.1
通讯作者：
Sirringhaus, Henning
中科院分区：
文献类型：
--
作者：
Selezneva, Ekaterina;Di Pietro, Riccardo;Sirringhaus, Henning
在过去的二十年中，随着对电子传输机制的理解的提高，新型半导体聚合物的开发取得了巨大进展，导致这些材料的电子迁移率急剧增加，使其成为电子和热电应用的有希望的候选者。热传输现象，另一方面，支配热导率，并没有得到尽可能多的关注。尽管热电性能测量原理简单，但热电优值zT的组合不确定性很容易达到50%，其中最大的不确定性来自热导率测量。这样的高测量不确定性，通常与在给定类别的材料内进行优化时遇到的zT的相对变化相当，阻碍了结构-热性能关系的研究。在这里，我们提出了一个协议，用于测量的热导率的薄膜与降低测量不确定性，这使我们能够调查的共轭聚合物P（NDI2OD-T2）的热导率的微观结构的变化的影响。我们表明，退火后的热导率的增强是不太明显的比相应的电子迁移率的增加，已报告在文献中相同的退火条件下。这表明，其中热传输仍然受到晶粒之间的非晶畴边界限制的半结晶共轭聚合物可以是用于实现电子晶体声子玻璃概念的合适系统，并且能够实现更高性能的热电材料。(c)2019年作者。除非另有说明，否则所有文章内容均根据知识共享署名（CC BY）许可证（http：//creativecommons.org/licenses/by/4.0/）进行许可。
Great progress in the development of new semiconducting polymers over the last two decades alongside improved understanding of electron transport mechanisms have resulted in a dramatic increase in the electron mobility of these materials making them promising candidates for electronic and thermoelectric applications. Heat transport phenomena, on the other hand-which govern thermal conductivity-have not received as much attention up to date. In spite of the simplicity of the principle behind the measurement of thermoelectric properties, the combined uncertainty in thermoelectric figure of merit zT could easily reach 50% with the largest uncertainty coming from thermal conductivity measurements. Such a high measurement uncertainty, often comparable to relative variations in zT encountered when optimizing within a given class of materials, prevents the study of structure-thermal property relationships. Here we present a protocol for the measurement of the thermal conductivity of thin films with reduced measurement uncertainty, which allowed us to investigate the effect of microstructural changes on the thermal conductivity of the conjugated polymer P(NDI2OD-T2). We show that the enhancement of the thermal conductivity upon annealing is much less pronounced than the corresponding increase in the electron mobility that has been reported under the same annealing conditions in the literature. This suggests that semicrystalline conjugated polymers in which thermal transport remains limited by the amorphous domain boundaries in between crystalline grains could be a suitable system for realizing the electron-crystal phonon glass concept and enable higher performance thermoelectric materials. (c) 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).