Precise monitoring of changes in ion concentration in electrolytic environments is of growing interest in multiple fields, such as bioelectronics, food packaging, agricultural sensing, and control of industrial chemical processes. However, combining sensitivity, ion-selectivity, and cost reduction has been proven to be a difficult task. In this work, we use an organic mixed ionic–electronic conductor [poly(3,4-ethlyenedioxythiophene) doped with poly(styrene sulfonate), PEDOT:PSS] to realize a sensor showing good selectivity and sensitivity to alkali ions without employing ion-selective membranes. We achieve this by combining a straightforward impedance analysis and static current–voltage measurement of an organic electrochemical transistor. We show that, after a calibration stage, the composition of unknown solutions can be determined. The ease of fabrication of this system, combined with the proposed measurement method and the potential biocompatibility of the organic semiconductor, makes such a sensor suitable for applications in biological environments, such as within the body or soil.

中文翻译：

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结合有机电化学晶体管和离子扩散阻抗分析的无膜选择性离子传感

电解环境中离子浓度变化的精确监测在生物电子学、食品包装、农业传感和工业化学过程控制等多个领域越来越受到关注。然而，将灵敏度、离子选择性和成本降低相结合已被证明是一项艰巨的任务。在这项工作中，我们使用有机混合离子 - 电子导体 [聚（3,4-乙撑二氧噻吩）掺杂聚（苯乙烯磺酸盐），PEDOT:PSS] 来实现一种传感器，该传感器对碱离子具有良好的选择性和灵敏度，而无需使用离子 -选择性膜。我们通过结合有机电化学晶体管的直接阻抗分析和静态电流-电压测量来实现这一点。我们表明，在校准阶段之后，可以确定未知溶液的组成。