Advances in copper nanocrystals: Synthesis, anti-oxidation strategies, and multiple applications

In recent years, copper (Cu) nanocrystals have garnered increasing interest in the field of metallic nanomaterials due to their low cost and excellent optical and electrical properties, positioning them as viable alternatives to noble metals such as Au and Ag. However, their susceptibility to oxidation in ambient conditions poses challenges for synthesis and practical applications. To address this, various anti-oxidation strategies have been developed, each offering distinct advantages. Despite growing research interest, a comprehensive review encompassing the synthesis, anti-oxidation strategies, and applications of Cu nanocrystals is currently lacking. This review systematically explores the preparation and shape-control techniques for Cu nanocrystals, covering diverse morphologies such as nanoparticles, nanowires, and nanosheets. It also provides an in-depth overview of existing anti-oxidation strategies, including surface capping and modification. Furthermore, the review highlights the multiple applications of Cu nanocrystals in optical and electrical domains, such as photocatalysis, electrocatalysis, sensing, luminescence, transparent conductive films, and nano-sintering. By elucidating the fundamental principles and mechanisms underlying each aspect, this review aims to offer comprehensive guidance for advancing research on Cu nanocrystals. Finally, it discusses the remaining challenges and future perspectives to enhance the applicability of Cu nanocrystals across various fields.