Evaporation induced hollow cracks and the adhesion of silver nanoparticle film

Abstract

Solution-based technology has potential in electrode patterning for low-cost, large-scale and flexible electronics. However, the formation of cracks often leads to unpredictable experimental results. This report explores the critical impact of solvent evaporation on the hollow crack formation and the adhesive property of silver nanoparticle film deposited using an ink-jet printable precursor ink. Uneven evaporation causes directional flows inside and along the surface of wet film, which contributes to nanoparticle film assembly initially at the periphery surface region. The area further away from the contact line tends to form thinner surface film, which can be easily deformed to form ripples under compressive stress. The suppressed evaporation of the liquid under the surface film makes the initially outward compensation flow reversed to inward, leaving a hollow inside morphology of the ripples, which can be transferred to cracks after complete solidification and will seriously degrade the adhesive property. This work has referential significance for the optimization of ink chemistry and film processing for high-quality film fabrication using solution-based method.