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 a great deal of attention, and in particular, cost-effective copper-based electrode materials have been recognized as viable candidates for replacement of the expensive silver counterpart. In this study, we synthesize newly designed Cu/Cu10Sn3 core/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 on a time scale of 10-3 s. By virtue of the low-melting point nature of the Cu10Sn3 phase, the facile electrode fabrication process is easily triggered, yielding resistivities of 27.8 and 12.2 μω cm under energy dose conditions of 0.97 and 1.1 J/cm2, respectively, at which highly conductive electrodes cannot be obtained from phase-pure Cu nanoparticles. The suspension mixture of Cu and Cu/Cu10Sn3 nanoparticles permits 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 substrate, while the electrodes derived from Cu10Sn3 phase-free Cu nanoparticles suffer from nonuniform characteristics and even a partially insulating nature. The practical applicability of Cu/Cu10Sn3 core/shell nanoparticles is demonstrated with the fabrication of a touch screen panel and an antenna for wireless power transmission.