Effect of sintering time on microstructure and conductivity of AJP silver electrode

Addressing challenges such as unclear mechanisms of microstructure evolution and difficulty in controlling conductivity during the sintering process of aerosol jet printing (AJP) silver electrodes in flexible electronic devices, this study systematically investigated the effect of varying sintering times (6–27 min) at 250 °C on the resistance and microstructure of polyimide-based silver electrodes. The structure–activity relationship between sintering time, microstructure, and resistance was elucidated through resistance measurements and scanning electron microscopy. The results indicate that after 15 min of sintering, the electrode is fully densified and exhibits its lowest resistance value (∼8 Ω). In contrast, shorter (6 min) or longer (27 min) sintering durations lead to increased electrical resistance due to insufficient densification, grain coarsening, and microcracking, respectively. A multiphysical field simulation model further reveals the synergistic mechanisms of interfacial reactions, particle coarsening, and microcrack formation during the over-sintering stage, with the model showing strong agreement with experimental results (R2 = 0.95). This study identifies an optimal sintering time window of 15 min at 250 °C for AJP silver electrodes, providing a theoretical foundation and experimental support for the optimization of post-treatment processes in flexible electronic devices. Potential industrial applications in wearable health monitoring and secure flexible systems, as well as future research directions, are briefly discussed.