Regulating the output performance of triboelectric nanogenerator by using P(VDF-TrFE) Langmuir monolayers

Highlights: • The Langmuir-Blodgett (LB) monolayer has been employed to regulate the electrification performance of TENG. • The polarity of output voltage from TENG can be reversed by depositing monolayers on the contact interface. • In-depth analysis in energy band diagram changed by Langmuir monolayers is proposed from the view of work functions. • Deposited LB monolayer can capture the injected charges during corona polarization, further improving the output of TENG. -- Abstract: The performance improvement of triboelectric nanogenerator (TENG) has always been an important issue. Herein, we report a surface modification method based on P(VDF-TrFE) deposited Langmuir monolayer to regulate the output performance of TENG. For the TENG using ITO electrode and polyethylene terephthalate (PET) film as the tribo-materials, the polarity of output voltage can be reversed by depositing a P(VDF-TrFE) monolayer on the surface of ITO. By using Kelvin probe measurement, we found that the dipole moment of monolayer can increase effective work function of ITO and the homogeneity of the monolayer in micro scale can also influence the performance of TENG. Through energy band diagram, the physical mechanism of charge transfer during contact electrification and the contribution of dipole monolayer to the electrification process are systematically illustrated. Moreover, the monolayer deposited on ITO electrode can capture electrostatic charges during corona polarization, which can further improve the output performance of TENG for more than 15 times. The surface modification methods introduced here can offer a simple but effective way to modulate the output performance of TENG, and our related physical analysis also helps to clarify the mechanism of contact electrification.