Room-temperature sintering of conductive Ag films on paper

• Silver nanoparticle-based ink has been synthesised for directly printing silver films on paper substrates with inkjet printer.
• Silver films can be sintered at room temperature by printing poly(diallyldimethylammonium chloride) solution.
• The mechanism of room temperature sintering was proposed based on the electrical and the morphological properties of silver films.

Water-dispersible Ag nanoparticles (NPs) were synthesised with polyacrylic acid as capping agents and prepared as an Ag NP-based ink. An approach to achieve coalescence and sintering of Ag NPs at room temperature was presented. After inkjet printing Ag NP-based ink on paper substrates, the Ag NPs underwent spontaneous coalescence when they came into contact with a poly(diallyldimethylammonium chloride) (PDAC) solution even without a traditional sintering process. This phenomenon rapidly decreased the sheet resistance of the films. The room-temperature sintering mechanism was then proposed based on the electrical and the morphological properties of Ag films with and without PDAC solutions.