Sintering of Silver Nanoparticles at Room-Temperature for Conductive Ink Applications

Abstract

Silver (Ag) nanoparticles synthesized in an aqueous system was sintered at room temperature using NaCl solution. The Ag nanoparticles have an average diameter of about 24 nm. After dispersing the Ag nanoparticles in 50mM NaCl solution, a significant increase in particle size to about 206 nm was observed. On the other hand, the particle size was also increased to about 175 nm when the Ag nanoparticles were printed and then 50mM NaCl solution was dropped onto the printed Ag nanoparticles. The enlargement of particle size was accompanied by the increase in conductivity of the Ag nanoparticle ink. The resistance was reduced from 57.7 to 6.5 and 6.7 ohms for the as-prepared and sintered Ag nanoparticles using two different treatments, respectively. The sintered Ag nanoparticle ink formulation exhibit high conductivity when drawn on both cellulose acetate film and bond paper even after bending and folding of the substrates.

On‐Demand Printing of Wearable Thermotherapy Pad

“…Halides are known to have strong interactions with Ag. The replacement destabilizes the Ag nanoparticles, which then leads to their close contact enabling them to coalesce or sinter as indicated by the necks formed among the larger nanoparticles . It is known that chemical sintering of certain silver nanoparticle inks can be facilitated by the presence of chloride.…”

“…The replacement destabilizes the Ag nanoparticles, which then leads to their close contact enabling them to coalesce or sinter as indicated by the necks formed among the larger nanoparticles. [30] It is Figure 1. A wearable heat pad for thermotherapy.…”

Fusing of Silver Nanoparticles at Room Temperature Using Halide Solutions for Conductive Inks

“…Generally, the fusing of the nanoparticles is triggered by the desorption of the polymer from the Ag surface as it is replaced by halide ions. Halides are known to have strong interactions with Ag [9][10][22][23][24]. The replacement destabilizes the Ag nanoparticles, which then leads to their close contact.…”

“…Magdassi et al sintered Ag nanoparticles at room temperature by a spontaneous three-dimensional coalescence process using poly(diallyldimethylammoniumchloride) (PDAC) as the sintering solution [10]. Halide salts solutions including MgCl2 and NaCl and acid halides such as HCl are commonly used as sintering agents [10,[22][23][24]. Ag nanoparticles after room temperature sintering exhibited electrical resistance ranging from 5 to 16 ohms when printed on a substrate.…”

Alternative Sintering Processes and Their Influence on the Electrical Resistance of Printed Ag Nanoparticle Conductive Networks

“…Apart from thermal sintering, numerous alternative sintering techniques have been explored, including chemical sintering, electrical sintering, photonic sintering, microwave sintering, and plasma sintering. − For example, ultraviolet (UV) sintering applies ultraviolet light to solidify and bind particles in the ink, creating conductive pathways. − This technique enables rapid curing and sintering at low temperatures, making it attractive for flexible electronics and printed circuits on heat-sensitive polymeric substrates . Despite its advantages, the major drawback of UV sintering is that high-intensity UV light might cause defects in the printed pattern, such as delamination, cavities, and cracks .…”