Effect of ink viscosity on electrical resistivity of narrow printed silver lines

Electrical properties of printed silver lines of varying widths are discussed. Conductive silver lines of widths 30-400 μm on polyimide substrates were fabricated by inkjet and screen printing with silver inks of two different viscosities. The printed lines with widths greater than 400 μm yielded excellent conductivities close to that of thin silver films regardless of ink viscosity. In contrast, the electrical resistivity of low viscosity ink lines narrower than 180 μm was much higher because of the coffee ring effect. The coffee ring effect must be reduced in narrow lines fabricated using low viscosity ink in order to improve their electrical performance.