High-conductivity screen-printable silver nanowire Ink for optically transparent flexible radio frequency electronics

Optically transparent conductors have paved the way in various optoelectronic and radio frequency (RF) devices where high electrical conductivity and optical transparency with mechanical flexibility, as well as large area fabrication are deemed necessary. Printing techniques are viable for fabricating large-area devices with high mechanical flexibilities. However, the preparation of suitable inks and printing recipes is essential to achieve a high electrical conductivity and transparency. In this study, the best tradeoff between conductivity and optical transmittance was achieved through silver (Ag) nanowires (NWs)-based ink formulation with tuned Ag NW loading, solvent compositions and polymer weight percentages. The ink was deposited through screen-printing, which enabled a large-area and high-resolution patterning of the AgNWs. The washing time of the post-printed films exhibited a decisive effect on the initial conductivity, which was further improved through photonic sintering. During the photonic sintering, the voltages, pulse lengths (μs) and fire rates (Hz) were optimized to obtain the best conductivity of the printed films. Maximum optical transparencies of 78 % and 83 % were achieved for the conductivities of ~5.88 × 106 and ~6.25 × 106 S/m, respectively. As a proof of concept, a fully printed optically transparent antenna was realized that could operate in a wide frequency band suitable for high-data-rate wireless communication.