Real-Time Acid Rain Sensor Based on a Triboelectric Nanogenerator Made of a PTFE–PDMS Composite Film

Self-powered sensors based on triboelectric nanogenerators (TENGs) are increasingly used in real-life applications, especially for monitoring water pollution, rain pH, and the like. Here, we fabricate a highly sensitive and self-powered acid rain sensor based on a TENG via a doping method. This device made of an optimum PTFE–0.07PDMS friction layer is very sensitive to proton concentrations. As an example, artificial acid rain (pH = 4) and normal water (pH = 7) droplets are used to test the responses of this developed sensor based on the TENG. Compared with the output differences (6.67 μA and 14.3 V) of a pristine device with a poly(tetrafluoroethylene) (PTFE) film, the output differences of the sensor with the PTFE–0.07PDMS film are enhanced to 26.37 μA and 69.04 V. The high sensitivity is attributed to the significant improvement of surface hydrophobicity, surface roughness, and the dielectric constant. Meanwhile, the good pH sensitivity and linearity of the sensor can be applied to real-time detection of acid rain in an actual environment. In short, this work provides a feasible strategy for a real-time acid rain sensor without an extra power source.