Femtosecond laser nanowelding of silver nanowires for transparent conductive electrodes

This work reports a method for nanowelding silver nanowires (AgNWs) using ultrashort laser pulses to minimize thermal damage on flexible substrates. Because of localized field enhancement and limited thermal diffusion, femtosecond laser irradiation enabled joining of AgNWs only at junctions, maintaining their original crystalline structure. The femtosecond laser nanowelding process produced neither breakup of the nanowire (NW) junction nor thermal aggregation. In addition, the sheet resistance and transmittance of the AgNW network were improved up to 25 Ω sq^-1 and over 94% at 550 nm, respectively. The femtosecond laser irradiation caused considerably less damage to a polymer substrate than nanosecond laser irradiation. The proposed nanowelding process is expected to serve as a useful tool to fabricate integrated plasmonic devices as well as transparent conducting electrodes on flexible substrates.