Highly conductive films sintered by Au–Ag nanoparticles ink at low temperature

Conducting films are becoming increasingly crucial for the electronics industry with applications in various technologies including high-power microelectronic packaging, photovoltaics, and flexible displays. The films with high conductivity were normally fabricated by sintering of printed inks with micrometer size particles. However, the resolution of printed pattern and high sintering temperature limit its application due to the particle size. Herein, we report a stable bimetallic alloy nanoparticle (Au–Ag) sintering inks with low sintering temperature (450 °C). The fabricated films have low resistivity (4.13 × 10–8 Ω·m), which is similar with that of bulk Au films (2.4 × 10–8 Ω·m) and show great adhesion on glass substrates. Film porosity is extremely low, with a maximum transmittance of only 0.1% in the wavelength range of 340 nm-870 nm. The Au–Ag nanoparticles sintering behavior was also characterized systematically by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was observed that the sintering process could be divided into three stages. This work indicates that this preparation approach of conductive film shows potential in the fabrication of highly integrated electronic devices by ink printing method.