Fabrication of Highly Conductive Inkjet Printing Silver Nanoparticle Ink via a Synergistic Strategy Combining Centrifugal Classification and Dispersant Optimization

Highlights: What are the main findings? A synergistic strategy integrating centrifugal classification, high-pressure homogenization, and dispersant optimization was successfully developed. The resulting optimized Ag NP ink demonstrated excellent jetting stability (clogging-free) and suitable rheology for reliable inkjet printing. A high electrical conductivity of 1.506 × 10⁷ S/m was achieved after low-temperature sintering at only 260 °C. Using Pluronic F127 as the sole dispersant allowed its complete removal during sintering, promoting the formation of a dense conductive network. What are the implications of the main findings? The strategy provides a scalable and practical manufacturing pathway for producing high-performance printed electronics. The low-temperature sintering capability (260 °C) makes the ink compatible with heat-sensitive flexible substrates. The complete removal of the dispersant eliminates insulating residues, which is crucial for achieving high conductivity in printed metal features. Inkjet printing technology shows significant potential for producing high-performance conductive circuits in printed electronics. However, conventional silver nanoparticle (Ag NP) inks often face challenges such as nozzle clogging, poor stability, and low conductivity after low-temperature sintering. While most existing studies focus solely on dispersant selection or individual process optimization, few have systematically explored the synergistic effects of particle size distribution, dispersion methods, and dispersant dosage. This study proposes a sequential optimization approach involving centrifugal classification to identify an optimal Ag NPs source and size distribution, followed by comparison and optimization of different dispersion methods. Furthermore, the effects of dispersant (a PEO-PPO-PEO triblock copolymer) concentration and application strategy (individual or combined use) on the rheological properties and conductivity of the ink were systematically investigated. The optimized Ag NP ink demonstrated excellent jetting stability with no nozzle clogging, exhibiting a surface tension of 19.60 mN/m and a viscosity of 6.83 mPa·s. After low-temperature sintering at 260 °C on glass or polyimide (PI) substrates, the printed patterns achieved a high electrical conductivity of 1.506 × 10⁷ S/m. Printing on polyethylene terephthalate (PET) at 150 °C confirmed compatibility with heat-sensitive flexible substrates. This work offers a comprehensive and practical strategy for developing highly reliable and conductive Ag NP inks, facilitating their application in next-generation printed electronics.