Performance enhancement of triboelectric nanogenerator through hole and electron blocking layers-based interfacial design

Enhancing negative charge retention sites on a contact surface is a key parameter to boost the performance of triboelectric nanogenerators. However, the unstable positive charge on the other contact surface can also be transferred as all surfaces have both charge donating and accepting regions. To prevent alternate charge transfer and charge recombination, PVDF is doped with phytate ion cluster as the tribopositive layer to trap positive charges through the formation of 18 hydrogen bonds or chelation through mono, di and trivalent cations of the 12 reactive phosphate groups, resulting in a 9.3-fold increase in current density. Moreover, the tribonegative layer is optimized with deeper trap states and more localization of negative charge (i.e. PDMS), which keeps tribocharges for longer duration of 5.5 h and results in a further 32-fold increase in current density to 4.4 mA m⁻². With the intrinsic charge trap enhancement, the device possesses high mechanical stability and durability, where the output performance remains intact after 16 month storage, due to the excellent compatibility of PVDF with phytate. Moreover, when four units of the device are stacked in parallel alternate layered form, an increase in output current from 1.1 µA to 20.9 µA with power density 0.80 W m⁻² was obtained, displaying potential of the device design for powering high demand wearable electronics.