The interaction mechanism of photogenerated carriers and piezoelectric charges of a photoactive piezoelectric nanogenerator

Abstract

Despite the fact that photoactive piezoelectric nanogenerators (PENGs) have been getting more attention due to their significant potential as a self-powered photodetector and pressure sensor, investigations on the interaction mechanism between photogenerated carriers and piezoelectric charges are still insufficient. In this study, photoactive PENGs based on methylammonium lead halides-poly(vinylidene) (MAPI-PVDF) composite were fabricated, in which the presence of MAPI in the PVDF matrix plays a dual role in enhancing the nucleation of the electroactive β-phase as well as inducing photoactivity in the composite. It has an optimal open-circuit voltage of 4.7 V and short-circuit current of 0.2 μA at 10 wt. % concentration of MAPI under illumination, which is nearly halved in the dark. Furthermore, we have thoroughly explored the interaction mechanism between photogenerated carriers and piezoelectric charges by piezoresponse scanning force microscopy techniques, photoluminescence spectroscopy, and a bandgap analysis. The results demonstrate that the photogenerated carriers screen part of the piezoelectric potential induced by the piezoelectric charges, while the piezoelectric charges promote more photogenerated carriers recombination. This work opens up horizons for the piezoelectric community in designing photoactive PENGs with multiple application modes and provides an effective approach to the development of piezoelectric materials.