Abstract
Microscopic interactions between electrochemical sensors and biomolecules critically influence the sensitivity. Here, we report an unexpected dependence of the sensitivity on the upper potential limit (UPL) in voltammetry experiments. In particular, we find that the sensitivity of substrate-supported nano-graphitic micro-sensors in response to dopamine increases almost linearly with the inverse of UPL in voltammetry experiments with rapid potential sweeps. Our experiments and multi-physics simulations reveal that the main cause behind this phenomenon is the UPL-induced electrostatic force that influences the steady-state number of dopamine molecules on the sensor surface. Our findings illustrate a new strategy for enhancing the performance of planar electrochemical micro-sensors.
•Unexpected sensitivity enhancement by reducing upper potential in voltammetry experiments employing rapid potential sweep.•Experimental and theoretical understanding of this unexpected phenomenon.•Record sensitivity to background charging current ratio (S–B ratio) as a result of this unexpected phenomenon.•Application of this phenomenon for the detection of bio-analytes at low concentrations.