Low-frequency noise (LFN) is of significant implications in ion sensing. As a primary component of LFN for ion sensing in electrolytes, the solid/liquid interfacial noise remains poorly explored especially regarding its relation to the surface binding/debinding dynamic properties. Here, we employ impedance spectroscopy to systematically characterize this specific noise component for its correlation to the dynamic properties of surface protonation (i.e., hydrogen binding) and deprotonation (i.e., hydrogen debinding) processes. This correlation is facilitated by applying our recently developed interfacial impedance model to ultrathin TiO₂ layers grown by means of atomic layer deposition (ALD) on a TiN metallic electrode. With an excellent fitting of the measured noise power density spectra by the model for the studied TiO₂ layers, we are able to extract several characteristic dynamic parameters for the TiO₂ sensing surface. The observed increase of noise with TiO₂ ALD cycles can be well accounted for with an increased average binding site density. This study provides insights into how detailed surface properties may affect the noise performance of an ion sensor operating in electrolytes.

中文翻译：

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低频噪声与电解质中传感表面动态特性的相关性

低频噪声（LFN）在离子感测中具有重要意义。作为用于电解质中离子感测的LFN的主要成分，固/液界面噪声仍未得到很好的研究，特别是关于其与表面结合/脱脂动力学特性的关系。在这里，我们采用阻抗谱来系统地表征这种特定的噪声成分，因为它与表面质子化（即氢键结合）和去质子化（即氢键脱脂）过程的动力学特性相关。通过将我们最近开发的界面阻抗模型应用于超薄TiO _2，可以促进这种相关性通过原子层沉积（ALD）在TiN金属电极上生长的有机层。通过所研究的TiO ₂层模型对测得的噪声功率密度谱的极佳拟合，我们能够提取TiO ₂传感表面的几个特征动态参数。观察到的随着TiO ₂ ALD循环而产生的噪声增加可以通过平均结合位点密度的增加得到很好的解释。这项研究提供了有关详细表面特性如何影响电解质中运行的离子传感器的噪声性能的见解。