Improvement in the Piezoelectric Performance of a ZnO Nanogenerator by a ZnO/Spiro‐MeOTAD ps‐n Heterojunction

Piezoelectric nanogeneratorsbased on ZnO nanowires (NWs) have attracted a wide attention in the applications of sustainable power source and self‐powered sensors. However, the output performance of ZnO nanogenerators is significantly suppressed by the piezoelectric potential screening effect due to the large excess electrons in ZnO NWs. In this work, the authors propose a facile and effective method to enhance the performance of ZnO nanogenerators by forming a ZnO/Spiro‐MeOTAD p‐n junction. The holes from the p‐type polymer remarkably reduce the free electrons in ZnO NWs through a depletion region and the polymer layer effectively decreases the ZnO surface‐state‐induced parasitic losses by surface passivation. By spin‐coating a layer of Spiro‐MeOTAD on ZnO NWs, a maximum current density of 500 nA cm⁻² is obtained which is approximately 10 times higher than that of the pristine ZnO‐NWs nanogenerators. The results obviously demonstrate the validity of a ZnO/Spiro‐MeOTAD p‐n junction structure for strengthening the performance of ZnO nanogenerators and provide a promising approach to realize high‐performance energy‐harvesting nanodevices.