Abstract

Significance Due to its wide bandgap， excellent optoelectronic properties， ease of preparation， low cost， and environmental friendliness， nano-ZnO has been extensively researched and applied. Conductive-doped nano-ZnO， with its advantages of optical transparency， high conductivity， and low cost， has emerged as a potential alternative to indium tin oxide （ITO） and holds great promise in fields such as antistatic coatings and optoelectronic films. Synthesizing nano-ZnO materials with good structural morphology， high conductivity， and optical transparency is crucial for leveraging ZnO’s application potential.

Progress Intrinsic ZnO exhibits n-type conductivity due to its inherent defects. However， its poor conductivity limits its application in antistatic materials. The thermodynamically stable wurtzite phase of ZnO can be n-doped by substituting Zn with Al or Ga， which has been proven to significantly increase the carrier concentration in ZnO， thereby enhancing its optoelectronic properties. The review discusses the liquid-phase preparation strategies for doped ZnO nanopowders， including the two-step synthesis， i. e. ， precursor conversion method and the one-step synthesis， i. e. ， in-situ doping method. The precursor conversion method involves converting mixed precursors into doped ZnO through high-temperature calcination， though the hightemperature process is hard to control. In contrast， the in-situ doping method allows for the one-step preparation of ZnO nanopowders through hydrothermal， solvothermal methods， or water-zinc chemical reactions under normal pressure， without the need for high-temperature post-treatment. By analyzing the nucleation and growth conditions of ZnO and the chemical behavior of impurity ions， morphology control and doping can be achieved， offering the advantage of easy scalability.

Conclusions and Prospects Al and Ga doping can effectively enhance the optoelectronic properties of ZnO. Nano-ZnO materials with unique structural morphologies help leverage the performance advantages of ZnO. For instance， one-dimensional nanomaterials with a certain aspect ratio are conducive to forming conductive networks in coatings， enhancing antistatic performance.The in-situ liquid-phase doping strategy offers controllability over the morphology and performance of the powder particles. However， further in-depth research at the microscopic level is required to clarify the doping mechanism in liquid-phase reactions.By combining analytical techniques such as XRD， XPS， ICP-OES， SEM， and TEM， the thermodynamic and kinetic behavior of ions， molecules， and atoms can be explained， and the relationship between the chemical processes in solution and the physical properties of the resulting crystals and their intrinsic defects can be clarified. This will provide guidance for the preparation and performance control of nanopowder materials and broaden the application scope of ZnO nanoparticles.

Keywords：ZnO nanopowder； doping； liquid phase； transparent conductive oxide； thermal control coating