Switchable textile-triboelectric nanogenerators (S-TENGs) for continuous profile sensing application without environmental interferences

Conventionally, the output amplitude of triboelectric nanogenerators (TENGs) sensors is detected as the sensing output, where the accuracy and stability are easily affected by environmental interferences such as humidity, temperature and electrostatic coupling with surrounding objects. Meanwhile, the nature of pulse mode voltage output cannot provide information to further generate a detailed profile of the varying force with time interval when users press a typical TENG working in the contact-separation mode. These two critical issues hinder the TENGs sensors to be competitive with conventionally commercialized sensors. In this study, a switchable textile-triboelectric nanogenerator (S-TENG) is proposed to address these issues. By working on a switchable mode to generate resistor-capacitor (RC) discharging voltage, i.e, enabling capacitive sensing, the capacitance of the TENGs device is not affected by environmental interferences. Moreover, a high-frequency switching approach is investigated to generate a continuous profile of time-dependent capacitance as a function of force along time, referring to the continuous sensing parameter. Therefore, S-TENGs offer the sensory information which could not be achieved by any other TENGs so far.