Opto-iontronic coupling in triboelectric nanogenerator

Triboelectric nanogenerator (TENG) has received tremendous attentions for its ability to convert mechanical energy into electrical energy. However, the induced current generated by TENG is an alternating-current (AC) signal and cannot directly satisfy most electronic devices that require direct-current (DC) supply. As a result, there has been a great number of interests in developing DC-TENG. Here, we have successfully developed an alternative to rectify TENG for DC output by coupling the electronic displacement current of TENG with ionic current, which could be further replenished by photocurrent. For the first time, an opto-iontronic current coupling in TENG was achieved under UV irradiation. A photogenerated electric field is triggered to remotely manipulate ion migration to complement the dissipation of ion concentration gradient. This permits the ionic current to be continually generated to rectify the electronic displacement current from the TENG in the opposite direction, while allowing coupling of both ionic and electronic current in the same direction. The opto-iontronic DC-TENG could be fabricated into one integrated flexible and thin device and the ionic charge could be remotely replenished by UV light. This study introduces a rectification paradigm for TENG and provides an effective method for in-situ AC-DC conversion, which could be potentially applied in wearable devices, bioelectronics, and self-powered intelligent sensors.