Metallic nanoparticle inks for flexible printed electronics

Abstract Flexible printed electronics represent a cutting‐edge technology leveraging functional inks to fabricate electronic circuits and components on diverse flexible substrates. Various advanced printing processes enable the production of computer‐controlled patterns with superior resolution and flexibility. Advances in low‐temperature sintering techniques have significantly propelled the evolution of flexible printed electronics by reducing thermal impact on substrates, ensuring high‐quality device fabrication. Functional nanomaterial inks serve as the cornerstone of this technology, with metallic nanoparticle inks being widely utilized for their superior electrical conductivity, facile synthesis, and commendable biocompatibility. Here, we comprehensively review the synthesis and processing of metallic nanoparticle inks and critically comment on different types of metallic nanoparticle inks, and believe that composite metallic nanoparticle inks have more advantages in reducing cost and improving comprehensive performance. In addition, this paper summarizes the various printing processes and sintering techniques, emphasizing the printing mechanisms and the recent advances in low‐temperature sintering technology. The applications of metallic nanoparticle inks in various scenarios, such as sensors, wireless technologies, energy storage and electroluminescent devices, are summarized. Lastly, the current challenges facing metallic nanoparticle inks are critically analyzed, and forward‐looking strategies and advances aimed at addressing these obstacles are proposed.