Femtosecond laser selective ablation of Cu/Ag double-layer metal films for fabricating high-performance mesh-type transparent conductive electrodes and heaters

Abstract

With the ultrashort timescale and high-power density, femtosecond laser is a powerful tool for localized material ablation with high processing accuracy and cleanliness. In this work, femtosecond laser direct writing was used to selectively ablate and remove the copper/silver (Cu/Ag) double-layer metal films on glass substrates for fabricating mesh-type transparent conductive electrodes (TCEs). In particular, the effects of laser fluence and laser scanning speed on surface morphology and photoelectric properties of the TCEs were studied. By using a laser fluence of 1.1 J/cm2 and a laser scanning speed of 400 mm/s, the optimal removal result of the Cu/Ag double-layer metal film was achieved with the minimal damage to the glass substrate. The as-obtained TCE showed a high average transmittance of 87.89% and a low sheet resistance of 1.36 Ω/sq. As an application, a transparent heater based on the as-obtained TCE exhibited an efficient, rapid and stable heating performance, being confirmed by achieving a high temperature of ∼144 °C under a low applied voltage of 2.0 V. The femtosecond laser selective ablation strategy for laser patterning of metal-based films provides a unique scheme for the rapid fabrication of metal mesh-type TCEs under the mask-free condition and room temperature.