Fig. 6: Optical responses of the sensors with and without the GO-MoS2-Au interface at various positions in the electrolyte.

a Schematic diagram and (b) recorded wavelength shifts of the sensor with the GO-MoS2-Au interface at a position 1/4 of the distance from the working electrode when the current was 0.25 mA. c Schematic diagram and (d) recorded wavelength shifts of the sensor with the GO-MoS2-Au interface at a position 1/4 of the distance from the counter electrode when the current was 0.25 mA. e Schematic diagram and (f) recorded wavelength shifts of the sensor with the GO-MoS2-Au interface at the middle position between the working electrode and the counter electrode when the current was 0.25 mA. g pH changes and (h) wavelength shifts at various positions in the electrolyte when the current was 0.25 mA. pH changes and recorded wavelength shifts at the working electrode when the electrolyte was potassium chloride. (i: current was 3 μA; k: current was 0.25 mA). pH changes and recorded wavelength shifts at the counter electrode when the electrolyte was potassium chloride (j: current was 3 μA; l: current was 0.25 mA)