Features of the formation of conductive films during thermal and laser sintering of silver nanoparticles stabilized by an ethoxylated carboxylic acid

Silver nanoparticles (Ag NPs) of ~ 6 nm in size were synthesized by the reduction of silver 2-[2-(2-methoxyethoxy)ethoxy]acetate by benzyl alcohol acting both as the solvent and as the reducer. The as-synthesized Ag NPs were dispersed in a mixture of nontoxic solvents with different boiling temperatures (butanol and propylene glycol ethers) to prepare ink. The ink was spin-coated on polyimide films and processed with thermal and laser sintering. After thermal sintering, the silver films have a non-uniform structure and contain many voids, causing their resistivity to be quite high (28 µΩ×cm). Laser sintering of the Ag NPs inks spin-coated on a polyimide film using a fiber laser operating at a wavelength of 1.064 µm in a pulse-periodic mode results in a uniform film structure, almost without voids, with a lower resistivity of 2.3 µΩ×cm. Laser sintering in this case is a promising method to fabricate conductive patterns on various substrates, including polymer flexible ones