Structure and Dopant Engineering in PEDOT Thin Films: Practical Tools for a Dramatic Conductivity Enhancement
Structure and Dopant Engineering in PEDOT Thin Films: Practical Tools for a Dramatic Conductivity Enhancement
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DOI：
10.1021/acs.chemmater.6b01035
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发表时间：
2016-05-24
影响因子：
8.6
通讯作者：
Simonato, Jean-Pierre
中科院分区：
文献类型：
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作者：
Gueye, Magatte N.;Carella, Alexandre;Simonato, Jean-Pierre
聚（3，4-乙撑二氧噻吩）（PEDOT）肯定是最知名和最常用的导电聚合物，因为它是可商购的，并且在有机电子、光伏和热电应用中显示出巨大的潜力。致力于PEDOT膜的研究已经导致高导电性增强。然而，仍然缺乏对这种增强机制的详尽理解，这受到材料本身的半结晶性质的阻碍。在这篇文章中，我们报告了高导电性PEDOT膜的发展，通过控制PEDOT链的结晶和随后的掺杂剂工程方法，使用铁（III）三氟甲磺酸盐作为氧化剂，N-甲基吡咯烷酮作为聚合速率控制剂和硫酸作为掺杂剂。XRD、HRTEM、同步加速器GIWAXS分析和低至3 K的电导率测量使我们能够解开这些高导电PEDOT材料的组织、掺杂和传输机制。N-甲基吡咯烷酮促进聚合过程中更大的微晶和结构增强，而硫酸处理允许由硫酸氢根取代三氟甲磺酸根阴离子，并增加载流子浓度。最后，我们提出了一个电荷输运模型，充分证实了我们的实验观察。这些聚合物表现出高达5400 S cm（-1）的电导率，因此显示出很大的前景，室温热电应用或透明电极的ITO替代品。
Poly(3,4-ethylenedioxythiophene) (PEDOT) is certainly the most known and most used conductive polymer because it is commercially available and shows great potential for organic electronic, photovoltaic, and thermoelectric applications. Studies dedicated to PEDOT films have led to high conductivity enhancements. However, an exhaustive understanding of the mechanisms governing such enhancement is still lacking, hindered by the semicrystalline nature of the material itself. In this article, we report the development of highly conductive PEDOT films by controlling the crystallization of the PEDOT chains and by a subsequent dopant engineering approach using iron(III) trifluoromethanesulfonate as oxidant, N-methyl pyrrolidone as polymerization rate controller and sulfuric as dopant. XRD, HRTEM, Synchrotron GIWAXS analyses and conductivity measurements down to 3 K allowed us to unravel the organization, doping, and transport mechanism of these highly conductive PEDOT materials. N-methyl pyrrolidone promotes bigger crystallites and structure enhancement during polymerization, whereas sulfuric acid treatment allows the replacement of triflate anions by hydrogenosulfate and increases the charge carrier concentration. We finally propose a charge transport model that fully corroborates our experimental observations. These polymers exhibit conductivities up to 5400 S cm(-1) and thus show great promise for room temperature thermoelectric applications or ITO alternative for transparent electrodes.