Enhanced morphology and conductivity in aerosol jet printing via optimization of print speed range under various deposition rate

• An optimal print speed range under commonly used deposition rate of aerosol jet printing for excellent morphology and conductivity is determined. • Internal porosity is the dominant factor affecting conductivity at low print speed, while continuity is the dominant factor affecting conductivity at higher speed. • The post-deposition spreading and airflow disturbance are the primary reasons leading the thickness reduction in multi-layer printing compared to single-layer printing at the same deposition amount. Aerosol Jet (AJ) printing is becoming increasingly attractive for printed conformal electronics due to its non-contact capability. However, the impact of deposition rate and print speed on the morphology and electrical properties of printed traces remains unclear. In this study, AJ printed traces with different print speed (0.3–20 mm/s) under commonly used deposition rate values (0.0002, 0.0004 and 0.0006 mm 3 /s) were examined. After evaluating the corresponding morphology and conductivity of the printed traces, the optimal print speed range of each deposition rate was determined as follows: deposition rate of 0.0002 mm 3 /s as 0.3–1.5 mm/s, 0.0004 mm 3 /s as 0.7–4 mm/s, and 0.0006 mm 3 /s as 1–6 mm/s, respectively. A three-dimensional computational fluid dynamics (CFD) model is proposed to elucidate the fundamental aerodynamic behaviors of AJ printed traces under different deposition rate, and its trends align with experimental observations. The mechanism by which print speed influences conductivity was analyzed, revealing that internal porosity is the primary factor reducing conductivity at low print speed. The analysis of morphology, conductivity, and printing efficiency across various print modes revealed that the morphology of printed traces under the respective deposition rate and print speed combination remained consistent in single-layer printing. Notably, printing efficiency is substantially enhanced at elevated deposition rate and high print speed. Compared to multi-layer printing at low deposition rate, high deposition rate single-layer printing emerges as the optimal method for achieving superior efficiency and conductivity. Ultimately, a correlation was established between resistance, print speed, and deposition rate, that enabling the successful printing of 15 resistors with specific resistance values (20 Ω) for different geometries, within an average error of 5.9 %, thereby broadening the applicability of AJ printing in printed electronics.