Facile preparation of stable reactive silver ink for highly conductive and flexible electrodes

Stability of conductive ink and mechanical flexibility of conductive pattern are essential for flexible printed electronics. In this work, we reported a stable reactive silver ink for the facile fabrication of flexible electrodes. The ink was mainly composed of silver-isopropanolamine (IPA) complex, formic acid reductant, and hydroxyethyl cellulose (HEC) adhesive agent, and it displayed good chemical stability. The flexible electrodes on polyimide (PI) substrates were achieved by mask-printing and thermal sintering of the ink, and the effects of sintering parameters and HEC adhesive agent content on the electrical and flexible properties and microstructure evolutions of silver layer were systematically investigated. Consequently, the silver layer sintered at 110 degrees C yields low electrical resistivity of 12.1 mu Omega.cm, which is only eight times higher than that of bulk silver. Furthermore, the sintered silver layer still presents excellent flexibility and low relative resistances after the bending, twisting, and folding tests. These results demonstrate that the stable reactive silver ink provides a promising and low cost opportunity for low temperature design and fabrication of high performance flexible printed electronics.