Microstructure engineering and conductivity optimization in silver films via Mixed Amine-MOD Ink

This study focuses on microstructure engineering by tailoring the composition of mixed-amine-based MOD (metal-organic decomposition) silver inks. By systematically varying the molar ratio of ethylamine (EA) and 1,2-diaminopropane (PDA) as complexing agents, we demonstrate a controllable approach to tuning the film morphology. The thermal behavior of the inks and the resulting silver films were analyzed in detail, including microstructure, porosity, mean particle size distribution, grain size, and resistivity. The use of mixed amines was found to significantly enhance particle packing density and reduce structural voids, which are critical for achieving high conductivity. Notably, at an EA:PDA molar ratio of 7:3, the silver films exhibited the most compact microstructure with minimal porosity and the lowest resistivity of 6.3 µΩ·cm when cured at 150 °C for 10 min. Furthermore, the printed lines demonstrated excellent mechanical stability, maintaining conductivity after 500 bending cycles. This work highlights the vital role of microstructure control in developing high-performance conductive films for flexible electronics.