Synthesis, properties and applications of ZnO nanomaterials with oxygen vacancies: A review

ZnO nanomaterials have attracted tremendous interest in the fields of photocatalysis, sensors, solar cells, supercapacitors, etc. However, the performance of intrinsic ZnO is limited by several factors such as insufficient light absorption, poor charge transport and low conductivity. Extensive studies have indicated that the controlled introduction of oxygen vacancies (V_O) into ZnO can manipulate their optical, electronic and surface properties, enabling their enhanced performance in various applications. Here, we present a state-of-the-art review on the various synthetic approaches of ZnO nanomaterials with V_O and their defect-related properties including structural characteristics, band structure, optical, electrical and ferromagnetic properties. In addition, their use in various applications such as photocatalysts, photoelectrodes, antibacterial agents, gas sensors, supercapacitors and other electronic devices related to V_O-rich ZnO are outlined. Furthermore, we offer some perspectives on the challenges and new directions in this field. We hope that this review would provide some useful information to the design, synthesis and applications of metal oxide nanomaterials with defects.