Performance of RGO paper-based pressure sensors. (a) Relative resistance change ΔR/R₀ dependence on pressure for 1 to 5 layer paper sensors, respectively, only with single coating of RGO; (b) ΔR/R₀ dependence on pressure for 5-layer paper sensor with 1 to 5 coating times, respectively. (c) Stability of a 5 L/5 C paper sensor with increasing loading. The step is 200 Pa. (d) Hysteresis characteristic curve of a 5 L/5 C paper sensor.