Fig. 4

Enhancing the sensitivity of liquid phase in situ infrared detection. a Schematic diagram of a liquid-phase GP infrared sensor. The black V is the voltage applied between the source and the drain electrodes, and the red V is the top-gate voltage. b The dashed curves represent experimental results (see details in Additional file 1: Note 5) of the extinction at different gate voltages \({\Delta V}_{\mathrm{g}}\), while the solid curves show the signals enhanced by CFW method. The experimental data were collected after \(1 \mathrm{mg}/\mathrm{mL}\) protein solution flowed for 2 h, with the graphene nanoribbon width being approximately \(50\; \mathrm{nm}\) and the period being approximately \(120\; \mathrm{nm}\). The characteristic vibrational peaks of the protein are marked by the vertical lines. c The simulation extinction map under different \({\Delta V}_{\mathrm{g}}\) by CFW method. The hollow points are the position of dips obtained from experimental results at different \({\Delta V}_{\mathrm{g}}\) (1.1 V, 1.3 V, 1.5 V, 1.7 V, 1.9 V, 2 V, 2.1 V) by the CFW method