Redox Monolayer Shot-noise

Redox monolayers are essential for various cutting-edge devices, such as high-frequency molecular diodes and biomolecular sensors. In our research, we introduced a novel formalism to elucidate the electrochemical shot noise originating from these monolayers, a phenomenon we have experimentally confirmed under ambient conditions in water. Our method consists in moving the equilibrium position of the system and measure its noise at each point, which in terms of measurements performance, effectively mitigates parasitic capacitance, thereby enhancing sensitivity. Furthermore, it enables the extraction of quantitative insights, including electronic coupling strength (standard electron transfer rates), its dispersion, and the determination of molecular counts within the monolayer. Unlike traditional solid-state physics, where energy levels and transfer rates are disparate, redox monolayers exhibit remarkable homogeneity, resulting in a characteristic Lorentzian noise spectrum. This groundbreaking exploration of shot noise in molecular electrochemical systems offers exciting prospects for quantum transport investigations in room-temperature liquids and advances sensitive bioelectrochemical sensors.