Improvement in piezoelectric performance of a ZnO nanogenerator by modulating interface engineering of CuO-ZnO heterojunction

In this paper, we demonstrate an approach of enhancing the output performance of nanogenerators (NGs) by modulating interface engineering of ZnO-CuO nano-heterojunctions. By properly modulating the preparation technology sequence of ZnO-CuO PN junctions, excessive electrons in ZnO can be effectively suppressed. By utilizing this approach, we obtained an output current up to ∼1200 nA measured under the same compressive force of ∼1 kgf, which is a 25-fold higher output current compared with that of the NG based on pure ZnO NWs. The corresponding working mechanisms were also discussed in this paper by using an interface energy band theory. This work may provide a potential approach to boosting the piezoelectric performance of the NGs based on ZnO-CuO PN junctions.