Well-Controlled Decomposition of Copper Complex Inks Enabled by Metal Nanowire Networks for Highly Compact, Conductive, and Flexible Copper Films

Highly compact and conductive Cu films are successfully fabricated by introducing mechanically robust and highly conductive metal nanowires (NWs) as fillers and optimizing amine-based ligands in Cu complex inks. The metal NWs (AgNWs and CuNWs) dispersed in the complex inks provide networks of nucleation sites for the in situ formed Cu particles and thereby control the decomposition of Cu complex inks at low temperatures to realize Cu films with high uniformity and integrality. The high affinity between metal NWs and the in situ formed Cu element enables the growth of Cu particles along the metal NWs to create a compact structure. Besides, the amine-based ligands such as 2-amino-2-methyl-1-propanol (AMP), 2-ethylhexylamine (Ethy), and hexylamine (Hexy) are varied to adjust the size of Cu particles and further improve the microstructure and conductivity of the sintered Cu films. The Cu-Ethy complex/metal NW inks sintered at 140 degrees C exhibit the lowest resistivity of 14.9 mu omega cm, which is about one-third that fabricated from the pure Cu-AMP complex inks. The flexible light-emitting diode circuits and V-shaped dipole antennas prepared from the Cu complex/metal NW inks have excellent performance due to their outstanding conductivity and flexibility, showing great potential in the fabrication of cost-effective, flexible printed electronic devices.