Investigation the interaction between the pulsed ultraviolet laser beams and PEDOT:PSS/graphene composite films

This research aims to investigate the interaction between pulsed ultraviolet (UV) laser beams and transparent PEDOT:PSS/graphene composite films. The laser ablated microstructure on film surfaces provides the electrical isolation and prevents the electrical contact from each location for the projected capacitive touch screen. Before the laser processing, the surface roughness, microhardness, spectrum and cross-sectional view of PEDOT:PSS/graphene composite film were measured by an atomic force microscope, a nanoindenter, a spectrometer and a scanning electron microscope, respectively. The focused UV laser beam was irradiated along line patterns with an overlapping rate of 60% and the applied laser fluences much over the ablation thresholds of 1.27 J/cm2 to 3.82 J/cm2. The surface morphology, three-dimensional topography, and cross-sectional profile of isolated lines and electrode structures after laser microstructuring were measured by a confocal laser scanning microscope. By increasing the laser fluence from 1.27 J/cm2 to 3.82 J/cm2, the ablated line widths and depths increased from 12.17 ± 0.24 μm to 21 ± 0.37 μm and from 190 ± 9 nm to 227 ± 15 nm, respectively. Moreover, the ablated lines of microstructuring electrodes had a clear and regular ablated edge quality.