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Noise Characteristics of Nanoscaled Redox-Cycling Sensors: Investigations Based on Random Walks

During the last years researchers at the University of Twente (MESA+) and the Forschungszentrum Jülich (PGI-8) have worked together to investigate noise characteristics of electrochemical sensors. Within this corporation, they recently developed a versatile framework for the simulation of molecular processes in nano-electrochemical devices. Their work provides insight into stochastic phenomena that may lead to the development of new electrochemical devices in the future.




Noise Characteristics of Nanoscaled Redox-Cycling Sensors: Investigations Based on Random Walks

By Enno Kätelhön, Kay J. Krause, Pradyumna S. Singh, Serge G. Lemay, Bernhard Wolfrum

Published: J. Am. Chem. Soc., 2013, 135 (24), pp 8874–8881.


Noise Characteristics of Nanoscaled Redox-Cycling Sensors Simplified scheme of their approach: The simulation framework models the response of arbitrary nano-electrochemical sensors. Pathways of all active molecules are hereby formed through individual random walks in order to closely mimic Brownian motion. By this means, realistic sensor signals can be obtained.



We investigate noise effects in nanoscaled electrochemical sensors using a three-dimensional simulation based on random walks. The presented approach allows the prediction of time-dependent signals and noise characteristics for redox cycling devices of arbitrary geometry. We demonstrate that the simulation results closely match experimental data as well as theoretical expectations with regard to measured currents and noise power spectra. We further analyze the impact of the sensor design on characteristics of the noise power spectrum. Specific transitions between independent noise sources in the frequency domain are indicative of the sensor-reservoir coupling and can be used to identify stationary design features or time-dependent blocking mechanisms. We disclose the source code of our simulation. Since our approach is highly flexible with regard to the implemented boundary conditions, it opens up the possibility for integrating a variety of surface-specific molecular reactions in arbitrary electrochemical systems. Thus, it may become a useful tool for the investigation of a wide range of noise effects in nanoelectrochemical sensors.