As a promising candidate to replace the brittle and expensive transparent indium tin oxide (ITO) conductor, the use of silver nanowire (AgNW) networks still involves issues such as high-temperature post-treatments and poor substrate adhesion for industrial application. Here a room-temperature soldering and one-step solution method is developed to achieve high-performance Ag nanowire transparent conductive films (TCFs). A nonconductive binder is prepared from poly(dopamine) and alginic acid which contains abundant catechol and carboxylic acid functional groups. The drying of the binder on the Ag nanowire percolation networks induces tighter contact among the nanowires and strong adhesion to the substrate, simultaneously enhancing the electrical and mechanical properties without a high-temperature annealing process. As a result, a highly conductive and bendable AgNW film is demonstrated on a low-cost polyethylene glycol terephthalate (PET) substrate, showing an 89% optical transmittance at λ = 550 nm and a sheet resistance of 16.3 Ohm sq⁻¹. Its optical and electrical performances are superior to those obtained from the reported indium tin oxide (ITO) films. Moreover, the AgNW film exhibits strong adhesion to the substrate, maintaining its conductivity after 100 tape tests, and it still resists the tape test even after exposure to solvent for several hours. Most importantly, the film shows good reliability during long-term 85 °C/85% RH (relative humidity) aging, which has been rarely investigated although it is a critical requirement for industrial application. The advanced and wide-ranging features of the prepared AgNW film greatly contribute to its use as a transparent electrode in multifunctional flexible electronic devices.

Copper nanoparticles are an alternative for the currently used silver and gold nanoparticles in inkjet printing of conductive patterns because of the low cost and high electrical conductivity. However, a serious impediment to using copper nanoparticles for conductive inks is their spontaneous oxidation. This paper describes a simple, large-scale and high-throughput (0.2 M) process for the synthesis of copper nanoparticles in aqueous solution at room temperature in a short reaction period. The well-dispersed antioxidative copper pastes were prepared by dispersing the nanoparticles in an ethanol solution of lactic acid, and then depositing on glass slides. The resistivity of the conductive copper film was 14.0 ± 4.5 μΩ cm after annealing at 200 °C for 30 min in nitrogen, which was about eight times of the resistivity of bulk copper (1.7 μΩ cm). The copper nanoparticles and films were characterized by TEM, UV-vis, SEM, XRD and XPS. Lactic acid-stabilized copper nanoparticles showed relatively better disperse stability and resistance to oxidation than the other carboxylic acids. Furthermore, the copper film after annealing at 200 °C for 30 min in nitrogen showed antioxidative characteristics. It was experimentally proven that lactic acid could react with the copper oxides surrounding copper nanoparticles to form copper lactate, which was then reduced to copper in the annealing process.