High-performance piezoelectric composite nanogenerator based on Ag/(K,Na)NbO₃ heterostructure

In this study, Ag/(K,Na)NbO₃ heterostructure constructed by in-situ photoreduction reaction is firstly introduced to fabricate the flexible piezoelectric nanogenerator (p-NG). The chemical heterojunction can improve the partial voltage applied to the KNN particles during poling process, and significantly enhance the orientation of dipole moment under the electric field. The p-NG device with Ag/(K,Na)NbO₃ heterostructure generates two orders of magnitude higher output than the pure KNN-based device (240 VS. 3.5 V; 23 VS. 0.3 µA under mechanical stress of 0.1 MPa). The maximum instantaneous output power (1.13 mW) is higher than the previously reported lead-free composite-based piezoelectric nanogenerators. Moreover, these Ag/(K,Na)NbO₃-based p-NG devices retained the mechanical robustness and electrical properties after 1000 cycles in the durability test. In addition, nine commercial LEDs connected in series can be successfully illuminated by our p-NG device without any storage equipment.