Formulating nickel metal organic decomposition ink with low sintering temperature and high conductivity for ink jet printing applications

Conductive nickel patterns of conventional electronic devices prepared by traditional methods usually need expensive specialized equipment which has low flexibility in pattern customization, limiting the application of patterning on large area flexible substrates. Metal-organic decomposition (MOD) ink is the core of printing electronic technology. A low temperature nickel ink is formulated via the complexation reaction between nickel formate and ethanolamine with the addition of a formic acid additive. It is found that formaldehyde provides sufficient reducibility in the decomposition process and lowers the thermal decomposition of the ink by properly adjusting the amount of the ethanolamine ligand and formic acid additive. A possible reduction mechanism of ethanolamine and formic acid is proposed. The nickel film fabricated on a PI substrate presents a compact microstructure with a resistivity of 102.4 µΩ·cm after sintering at 250 °C. A series of lines with compact structure and with average relative width deviation of 5.4% are successfully printed under suitable resolutions. A functional planar micro-supercapacitor was fabricated by electrodepositing MnO 2 on the printed interdigital Ni electrode, which indicates that the Ni MOD ink is promising for ink jet printing and electronics applications.