The organic electrochemical transistor (OECT) has emerged as the core component of specialized bioelectronic technologies, such as neural interfaces and sensors of disease biomarkers. At the heart of the OECT is its channel, made of an organic mixed ionic–electronic conductor (OMIEC). The chemical structure of the OMIEC governs the electronic, optical and mechanical traits of OECT, with even subtle structural tweaks leading to sizeable functional disparities. In this Review, we summarize the recent progress in OECT device development while underscoring the critical role of OMIEC selection in steering diverse applications. Our narrative charts the milestones in materials exploration, tracing the evolution of the field in parallel with polymer chemistry breakthroughs. We emphasize how materials design has enabled new device operation mechanisms by adding features such as biocompatibility, stretchability, stimuli response and memory retention to OMIECs. We also highlight the obstacles that must be surmounted to translate OECT-based devices from laboratory instruments into tangible real-world technologies.

有机电化学晶体管（OECT）已成为专业生物电子技术的核心组件，例如神经接口和疾病生物标志物传感器。OECT 的核心是其通道，由有机混合离子电子导体 (OMIEC) 制成。OMIEC 的化学结构控制着 OECT 的电子、光学和机械特性，即使是细微的结构调整也会导致相当大的功能差异。在这篇综述中，我们总结了 OECT 设备开发的最新进展，同时强调了 OMIEC 选择在引导不同应用中的关键作用。我们的叙述描绘了材料探索的里程碑，追踪该领域与聚合物化学突破并行的演变。我们强调材料设计如何通过向 OMIEC 添加生物相容性、可拉伸性、刺激响应和记忆保留等功能来实现新的设备操作机制。我们还强调了将基于 OECT 的设备从实验室仪器转化为有形的现实世界技术时必须克服的障碍。