3D printing of highly conductive silver architectures enabled to sinter at low temperatures

• Published in: Nanoscale 2019-01, Vol.11 (38), p.17682-17688
• Main Authors: Kim, Jung Hyun, Lee, Sanghyeon, Wajahat, Muhammad, Ahn, Jinhyuck, Pyo, Jaeyeon, Chang, Won Suk, Seol, Seung Kwon
• Format: Article
• Language: English
• Subjects: 3-D printers; Acrylic acid; Annealing; Coalescing; Deposition; Diffusion; Electrical resistivity; Extrusion; Fused deposition modeling; Grain boundary diffusion; Heat resistance; High temperature; Inks; Low temperature; Nanoparticles; Organic chemistry; Silver; Sintering; Substrates; Thermal resistance; Three dimensional models; Three dimensional printing
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c9nr05894j

Silver (Ag) nanoparticle-based inks are frequently used in printed electronics to form conductive patterns, but often require high-temperature sintering to achieve the optimum electrical conductivity, hindering their use in substrates with poor heat resistance. Herein, a three-dimensional (3D) printing strategy to produce highly conductive Ag 3D architectures that can be sintered at low temperatures is reported. This strategy is based on the additive deposition of Ag nanoparticles and microflakes via extrusion-based 3D printing with the Ag ink that involves poly(acrylic acid) (PAA)-stabilized Ag nanoparticles, Ag microflakes, and NaCl a destabilizing agent. The designed Ag inks are stable and suitable for ink-extrusion 3D printing. In chemical sintering, Cl can detach PAA from the Ag nanoparticle surface, enabling nanoparticle coalescence and sintering. An elevated annealing temperature induces increased NaCl density in the printed patterns and accelerates the surface and grain boundary diffusion of Ag atoms, contributing to enhance chemical sintering. On annealing at 110 C for 30 min, the printed structures exhibited an electrical conductivity of 9.72 10 4 S cm 1 , which is 15.6% of that of bulk Ag. Complicated Ag architectures with diverse shapes were successfully fabricated on polymeric substrates. Several structural electronic applications were demonstrated by hybrid 3D printing combining our extrusion-based 3D printing and conventional fused deposition modeling (FDM). Highly conductive 3D Ag architectures are realized by extrusion-based 3D printing using Ag inks enabled to sinter at low temperatures.