pH monitoring in high ionic concentration environments: performance study of graphene-based sensors

Graphene-based pH sensors, acclaimed for their exceptional sensitivity to environmental variations, have garnered significant interest in scientific research. However, the sensor performance in high ionic concentration environments is limited, due to the Debye length ion screening effect. In this study, an innovative graphene channel pH sensing device was developed and modified by cross-linked poly(methyl methacrylate) (PMMA). Furthermore, even in high ionic concentrations, the pH value can be precisely measured by this sensor. The sensor has remarkable sensitivity, and high response rate of − 70.49 mV/pH within the pH range from 7 to 10. Notably, the sensors retain uniform response direction and sensitivity under different ionic concentrations environmental and maintain consistent reversibility and stability. This advancement in sensor technology paves the way for broader applications in complex ionic environments.

Left : A graphene-based pH sensor modified with a cross-linked PMMA film; Right : Sensitivity comparison of graphene-based sensors to pH under different electrolyte concentrations. This work presents a cross-linked PMMA film-modified graphene-based pH sensor that maintains high sensitivity even in high ionic strength environments.