Vibrational entropy as an indicator of temperature coefficient of redox potential in conjugated polymers
Vibrational entropy as an indicator of temperature coefficient of redox potential in conjugated polymers
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DOI：
10.7567/1347-4065/ab3b67
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发表时间：
2019-09
影响因子：
1.5
通讯作者：
H. Iwaizumi;Tomotsugu Sugano;T. Yasuda;Y. Shimoi;W. Kobayashi;Y. Moritomo
中科院分区：
文献类型：
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作者：
H. Iwaizumi;Tomotsugu Sugano;T. Yasuda;Y. Shimoi;W. Kobayashi;Y. Moritomo
最近，通过使用阴极和阳极材料之间的氧化还原电势（V）的热系数α（= dV/dT）的差异，证明了环境热可以使电池处于充电状态。在该电池中，α是决定器件性能的关键参数。在这里，我们系统地研究了典型的共轭聚合物，即聚噻吩和四个芴基聚合物中的α。我们发现，α随主链中噻吩的数量比（r）而急剧增加，从r = 0.0时的0.19 mV K−1增加到r = 1.0时的1.08 mV K−1。这种趋势是很好地理解的组成分子的中性和氧化态之间的振动熵Svib的变化。
Recently, it was demonstrated that environmental heat can put a battery on the charged state by using the difference in the thermal coefficient α (= dV/dT) of the redox potential (V) between the cathode and anode materials. In this battery, α is the key parameter that determines the device performance. Here, we systematically investigated α in prototypical conjugated polymers, i.e. polythiophene and four fluorene-based polymers. We found that α steeply increases with the number ratio (r) of thiophene in the main chain from 0.19 mV K−1 at r = 0.0 to 1.08 mV K−1 at r = 1.0. This trend is well understood in terms of variation of the vibrational entropy Svib between the neutral and oxidized states of the constituent molecule.