Newly Designed Cu/Cu₁₀Sn₃ Core/Shell Nanoparticles for Liquid Phase-Photonic Sintered Copper Electrodes: Large-Area, Low-Cost Transparent Flexible Electronics

Abstract

The conductive nanomaterials applicable to unconventional printing techniques have attracted the tremendous attention, and in particular, cost-effective copper-based electrode materials have been recognized a viable candidate to replace the expensive silver counterpart. In this study, we synthesize newly-designed Cu core/Cu 10 Sn 3 shell nanoparticles, as an additive material for overcoming the critical drawbacks in Cu nanoparticle-based electrodes, in combination with a large-area processable, continuous photonic sintering process in a time scale of 10 -3 sec. By virtue of a low melting-point nature of Cu 10 Sn 3 phase, the facile electrode fabrication process is easily triggered, evolving the resistivities of 27.8 and 12.2 µΩ·cm under energy dose conditions of 0.97 and 1.1 J/cm 2 , respectively, at which highly conductive electrodes are not obtainable from phase-pure Cu nanoparticles. The mixture suspension of Cu and Cu/Cu 10 Sn 3 nanoparticles enables for roll-to-roll processable, highly uniform Cu-based electrodes (with a sheet resistance and a standard deviation of 1.21 and 0.29 Ω/square, respectively) even on vulnerable polyethylene naphthalate (PEN) substrate, while the electrodes derived from Cu 10 Sn 3 phase-free Cu nanoparticles suffer from non-uniform characteristics and even a partially insulating nature.The practical applicability of Cu/Cu 10 Sn 3 core/shell nanoparticles is demonstrated with the fabrication of a touch screen panel and an antenna for wireless power transmission.

Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics

“…Cu-Sn: Oh et al synthesized Cu-Cu10Sn3 core-shell nanoparticles for producing highly conductive electrodes in combination with a large-area processable, continuous photonic sintering process, which allowed for the use of an R2R process [ 95 ]. The melting point (798 °C) of Cu10Sn3 phases is lower than that of bulk Cu (1059 °C).…”

Liquid Metal‐Based Soft Electronics for Wearable Healthcare

“…Although metals and their micro‐ and nanostructures have excellent conductivity, the inherent rigidity prevents their utilization as a biomedical application. [ 10,11 ] Also, conductive polymers, hydrogels, and ionic liquids, which present soft and fluidic behaviors, fail to achieve complex data processing and signal transfer because of their low electrical conductivity. [ 12,13 ] In the case of the active materials that respond to the external stimuli, the performances of newly developed carbon‐based materials and organic semiconductors are insufficient to substitute the conventional brittle materials, such as oxides or silicon.…”

Form‐Factor Free 3D Copper Circuits by Surface‐Conformal Direct Printing and Laser Writing

“…The kinetically controlled flash‐light sintering (FS) process, carried out at a timescale of 10 −3 s in air, has opened up a new possibility for suppressing such undesirable oxidation reactions. [ 25–27 ] However, this lamp‐based irradiation technique cannot be used on top of arbitrary structures with different heights in the vertical direction. The laser sintering (LS) process allows for conformal irradiation along the surface geometry of arbitrary structures.…”