Oxidative Molecular Layer Deposition of Amine-Containing Conjugated Polymer Thin Films
Oxidative Molecular Layer Deposition of Amine-Containing Conjugated Polymer Thin Films
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含胺共轭聚合物薄膜的氧化分子层沉积
DOI：
10.1021/acsapm.2c00942
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发表时间：
2022
影响因子：
5
通讯作者：
Young, Matthias J.
中科院分区：
文献类型：
--
作者：
Wyatt, Quinton K.;Vaninger, Mitchel;Paranamana, Nikhila C.;Heitmann, Thomas W.;Kaiser, Helmut;Young, Matthias J.
聚乙烯二氧噻吩（pEDOT）、聚吡咯（pPy）和聚苯胺（pAni）等共轭聚合物表现出很高的电化学容量，使它们成为储能、电化学脱盐和化学传感的电极材料。最近的工作已经建立了pEDOT薄膜的生长，使用EDOT单体和金属氯化物（例如MoCl5）氧化剂在称为氧化分子层沉积（oMLD）的过程中交替气相暴露。在这里，我们描述了含胺共轭聚合物的oMLD的第一个演示。我们发现吡咯（Py）和mocl5在oMLD暴露过程中发生自限制表面反应形成保形pPy薄膜，但使用苯胺（Ani）和对苯二胺（PDA）单体的oMLD产生意想不到的偶氮功能。偶氮基团的形成归因于mocl5 -胺表面加合物，该加合物在空间上限制了胺基附近的聚合反应，并在两个伯胺偶联时产生偶氮基团。由oMLD生长的pPy在水电解质中表现出创纪录的282 mAh/g容量，PDA/MoCl5oMLD产生偶氮聚合物作为碱离子电池的负极材料。在oMLD过程中，在Py和PDA单体之间交替产生的分子组装共聚物与分离的单体结构具有质量不同的电化学响应。这项工作为在分子水平上控制其组成和厚度的共轭胺聚合物共形薄膜的生长奠定了基础。
Conjugated polymers such as polyethylenedioxythiophene (pEDOT), polypyrrole (pPy), and polyaniline (pAni) exhibit high electrochemical capacities, making them appealing as electrode materials for energy storage, electrochemical desalination, and chemical sensing. Recent work has established the growth of thin films of pEDOT using alternating gas-phase exposures of the EDOT monomer and a metal chloride (e.g., MoCl5) oxidant in a process termed oxidative molecular layer deposition (oMLD). Here, we describe the first demonstration of oMLD of amine-containing conjugated polymers. We find that pyrrole (Py) and MoCl5undergo self-limiting surface reactions during oMLD exposures to form conformal pPy thin films, but oMLD using aniline (Ani) andp-phenylenediamine (PDA) monomers yields unexpected azo functionality. The formation of azo groups is attributed to an MoCl5-amine surface adduct that spatially constrains polymerization reactions near the amine group and produces azo groups when coupling two primary amines. pPy grown by oMLD exhibits a record-breaking 282 mAh/g capacity in an aqueous electrolyte, and PDA/MoCl5oMLD yields azo polymers of interest as anode materials for alkali-ion batteries. Alternating between Py and PDA monomers during oMLD produces molecularly assembled copolymers with qualitatively different electrochemical responses from the isolated monomer structures. This work lays the foundation for the growth of conformal thin films of conjugated amine polymers with molecular-level control of composition and thickness.