Quantitative Dedoping of Conductive Polymers
Quantitative Dedoping of Conductive Polymers
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DOI：
10.1021/acs.chemmater.6b04880
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发表时间：
2017-01-24
影响因子：
8.6
通讯作者：
Moule, Adam J.
中科院分区：
文献类型：
--
作者：
Jacobs, Ian E.;Wang, Faustine;Moule, Adam J.
尽管掺杂是无机半导体行业的基石，但大多数使用有机半导体 (OSC) 的器件都使用本征（未掺杂）材料。 OSC 掺杂的最新工作重点是使用掺杂剂来改变材料的物理特性，例如除了电子和光学特性之外，溶解度。然而，如果要在器件制造中利用这些效应，则需要一种对有机半导体进行去掺杂的方法。在这里，我们概述了 OSC 薄膜去掺杂的两种化学策略。在第一个策略中，我们使用电子供体（叔胺）作为竞争性供体。该过程基于供体电离和 OSC 之间的热力学平衡，并且仅导致部分去掺杂。在第二种策略中，我们使用电子供体，该电子供体随后与 p 型掺杂剂反应以产生非掺杂产物分子。伯胺和仲胺与掺杂剂分子 2,3,5,6-四氟-7,7,8,8,-四氰基醌二甲烷 (F4TCNQ) 发生快速加成反应，伯胺进一步发生反应消除 HCN。在优化条件下，用 1-丙胺 (PA) 脱掺杂的半导体聚合物聚 (3-己基噻吩) (P3HT) 薄膜在接触胺后 5 秒内达到铸态荧光强度，最终达到铸态值的 140%。去掺杂后场效应迁移率同样恢复。即使在高荧光聚合物（例如 PFB）中也可以进行定量荧光恢复，预计这些聚合物对残留掺杂剂更加敏感。有趣的是，用 PA 处理未掺杂的薄膜也会增加荧光强度，并将电导率降低至少 2 个数量级。这些结果表明，该工艺不仅定量去除了 F4TCNQ，而且还去除了铸态薄膜中存在的固有 p 型杂质。本文概述的去掺杂策略通常适用于 OSC 薄膜中的其他 p 型和 n 型分子掺杂剂。
Although doping is a cornerstone of the inorganic semiconductor industry, most devices using organic semiconductors (OSCs) make use of intrinsic (undoped) materials. Recent work on OSC doping has focused on the use of dopants to modify a material's physical properties, such as solubility, in addition to electronic and optical properties. However, if these effects are to be exploited in device manufacturing, a method for dedoping organic semiconductors is required. Here, we outline two chemical strategies for dedoping OSC films. In the first strategy, we use an electron donor (a tertiary amine) to act as competitive donor. This process is based on a thermodynamic equilibrium between ionization of the donor and OSC and results in only partial dedoping. In the second strategy, we use an electron donor that subsequently reacts with the p-type dopant to create a nondoping product molecule. Primary and secondary amines undergo a rapid addition reaction with the dopant molecule 2,3,5,6-tetrafluoro-7,7,8,8,-tetracyanoquinodimethane (F4TCNQ), with primary amines undergoing a further reaction eliminating HCN. Under optimized conditions, films of semiconducting polymer poly(3-hexylthiophene) (P3HT) dedoped with 1-propylamine (PA) reach as-cast fluorescence intensities within 5 s of exposure to the amine, eventually reaching 140% of the as-cast values. Field-effect mobilities similarly recover after dedoping. Quantitative fluorescence recovery is possible even in highly fluorescent polymers such as PFB, which are expected to be much more sensitive to residual dopants. Interestingly, treatment of undoped films with PA also yields increased fluorescence intensity and a reduction in conductivity of at least 2 orders of magnitude. These results indicate that the process quantitatively removes not only F4TCNQ but also intrinsic p-type impurities present in as-cast films. The dedoping strategies outlined in this article are generally applicable to other p- and n-type molecular dopants in OSC films.