Sources and Mechanism of Degradation in p-Type Thiophene-Based Organic Electrochemical Transistors
Sources and Mechanism of Degradation in p-Type Thiophene-Based Organic Electrochemical Transistors
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DOI：
10.1021/acsaelm.1c01171
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发表时间：
2022-04
影响因子：
4.7
通讯作者：
Emily A. Schafer;Ruiheng Wu;D. Meli;J. Tropp;Maximilian Moser;Iain McCulloch;Bryan D. Paulsen;J. Rivnay
中科院分区：
文献类型：
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作者：
Emily A. Schafer;Ruiheng Wu;D. Meli;J. Tropp;Maximilian Moser;Iain McCulloch;Bryan D. Paulsen;J. Rivnay
实现高稳定性对于有机电化学晶体管（OECT）在更多样化和要求更高的应用中的实现至关重要。然而，OECT降解的来源和机制尚未得到严格的探索。在这里，我们采用了各种偏置方案分离氧化偏置应力，还原偏置应力，和电流应力对噻吩为基础的，p型OECT降解的相对影响。我们发现，加速降解产生的复合效应的同时氧化和还原偏置应力，是常见的几个噻吩为基础的通道材料。为了理解OECT沟道退化的潜在机制，我们探索了溶解氧和源漏电极材料的单独贡献。我们确定，溶解氧在经历还原电位的漏电极的掩埋的Au/OMIEC界面处的反应产生移动的反应性物质，该反应性物质在整个装置中积极地降解氧化的OMIEC，破坏其共轭并破坏电子电荷传输。重要的是，我们发现，这种机制可以通过交替地去除氧气，避免还原电位的设备偏置方案，取代Au电极与非催化替代品，或钝化Au电极与自组装单分子层。这些结论可以告知未来的标准，在现场的稳定性测试，以及在长期应用中的OECT实施的设计考虑。
Achieving high stability is critical for the implementation of organic electrochemical transistors (OECTs) in more diverse and demanding applications. However, the sources and mechanisms of OECT degradation have not been rigorously explored. Here, we employ a variety of biasing schemes to separate the relative effects of oxidative bias stress, reductive bias stress, and current stress on degradation of thiophene-based, p-type OECTs. We find that accelerated degradation arises from the compounding effects of simultaneous oxidative and reductive bias stress and is common across several thiophene-based channel materials. To understand the underlying mechanism of OECT channel degradation, we explore the individual contributions of dissolved oxygen and source-drain electrode materials. We determine that the reaction of dissolved oxygen at the buried Au/OMIEC interface of the drain electrode experiencing reductive potentials produces a mobile reactive species that aggressively degrades the oxidized OMIEC throughout the device, destroying its conjugation and disrupting electronic charge transport. Importantly, we find that this mechanism can be disrupted by alternatively removing oxygen, avoiding reductive potentials in the device biasing scheme, replacing Au electrodes with a noncatalytic alternative, or passivating Au electrodes with self-assembled monolayers. These conclusions can inform both future standards of stability testing in the field as well as design considerations of OECT implementation in long-term applications.