n-type charge transport in heavily p-doped polymers
n-type charge transport in heavily p-doped polymers
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DOI：
10.1038/s41563-020-00859-3
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发表时间：
2021-01-04
期刊：
影响因子：
41.2
通讯作者：
Graham, Kenneth R.
中科院分区：
文献类型：
--
作者：
Liang, Zhiming;Choi, Hyun Ho;Graham, Kenneth R.
通常认为，掺杂的p-共轭聚合物中的电荷载流子传输由一种类型的电荷载流子（空穴或电子）主导，这由掺杂剂的化学性质决定。在这里，通过塞贝克系数和霍尔效应的测量，我们表明，移动的电子大大有助于p共轭聚合物中的电荷载流子输运是重p掺杂强电子受体。具体而言，几种p掺杂聚合物的塞贝克系数随着氧化剂FeCl 3或NOBF 4的浓度增加而从正变为负，并且对相同p掺杂聚合物的霍尔效应测量揭示电子成为主要的离域电荷载流子。紫外和逆光电子能谱测量表明，掺杂氧化剂的结果在高掺杂浓度下的输运间隙的消除。这种重p型掺杂的方法被证明是提供一个有前途的路线，以高性能的n型有机热电材料。
It is commonly assumed that charge-carrier transport in doped p-conjugated polymers is dominated by one type of charge carrier, either holes or electrons, as determined by the chemistry of the dopant. Here, through Seebeck coefficient and Hall effect measurements, we show that mobile electrons contribute substantially to charge-carrier transport in p-conjugated polymers that are heavily p-doped with strong electron acceptors. Specifically, the Seebeck coefficient of several p-doped polymers changes sign from positive to negative as the concentration of the oxidizing agents FeCl3 or NOBF4 increase, and Hall effect measurements for the same p-doped polymers reveal that electrons become the dominant delocalized charge carriers. Ultraviolet and inverse photoelectron spectroscopy measurements show that doping with oxidizing agents results in elimination of the transport gap at high doping concentrations. This approach of heavy p-type doping is demonstrated to provide a promising route to high-performance n-type organic thermoelectric materials.