Laser Micromachining of PEDOT:PSS/Graphene Thin Films by Using Beam Shaping Technology

This study investigated the interaction between square top-hat laser beams and PEDOT:PSS [poly(3,4-ethylene dioxythiophene):poly(4-styrene sulfonate)]/graphene thin films by using ultravi-olet (UV) laser-beam-shaping technology for electrode patterning. This novel laser process can re-duce the number of fabrication steps and quantity of chemical solutions and can improve the remov-al efficiency of graphene films. The laser processing parameters were the laser pulse energy, pulse repetition frequency, and feeding rate of a motorized XY-axis positioning table for ablating the gra-phene thin films. The square top-hat laser beam was irradiated along line patterns with the applied laser fluences markedly over the ablation thresholds of 1.41 to 2.5 J/cm2. Increasing the laser flu-ence from 1.41 to 2.5 J/cm2 increased the ablated line widths and depths from 35.61 ± 0.28 to 43.23 ± 0.21 µm and from 224 ± 10 to 279 ± 9.29 nm, respectively. The ablated lines of the microstruc-tured electrodes had a clear, smooth, and regular ablated edge quality. Moreover, a maskless laser direct writing process yielded patterned film structures that provide electrical isolation and prevent electrical contact from each region.