| Abstract [eng] |
Due to its outstanding electrical, thermal and optical properties, graphene is widely used in sensors, batteries, flexible displays, supercapacitors and solar cells. Laser-induced graphene (LIG) is a simple process that allows laser radiation to interact with materials to create flexible components for energy storage devices, supercapacitors, water-degrading electrocatalysts, piezoelectric strain gauges, electrochemical biosensors, photodetectors, sensors and more. In addition, the process allows the modification of polymers that are less difficult to integrate with the electrode, which is very useful in planar or flexible systems. Polyimide (PI) and polyetherimide (PEI) make it easy to tailor the properties (conductivity and morphology) of graphene to different applications, optimizing the laser process. Despite many reports on LIG on PI and other polymers, only a few recent studies have reported LIG on PEI, which is investigated in this work. Aim of the work: laser-initiated formation of electrically conductive structures in polyetherimide using picosecond and nanosecond lasers at 1064 and 532 nm. The LIG fabrications are compared in terms of surface morphology, resistivity and Raman spectroscopy. The study conducted analysis of laser micro-patterning on polyetherimide (PEI) polymer and the optimal results were consistently achieved with a laser scanning speed of 5 mm/s and a power range of 500-700 mW, positioning the PEI sample surface at the focal point (0,6 – 0,84 J/cm2) or 1 mm above it (0,13 – 0,19 J/cm2). The lowest resistance was obtained using a nanosecond laser at 532 nm, resulting in an average resistance of 4 Ω. This was achieved by scanning the area at least twice with 600 mW (focal point 0,72 J/cm2 and 1 mm above it 0,16 J/cm2) power and a scanner speed of 5 mm/s. The four-probe method revealed the lowest surface resistivity of 13.6 Ω/sq with a 532 nm nanosecond laser at the focal point, using 600 mW power, with scanning the area at least twice with scanner speed of 5 mm/s and with 1064nm at the focal point, 500 mW (0.13 J/cm2), scanned x2 times and obtained a value of 13.6 Ω/sq. With SEM It was observed that 532 nm has distinctly more regular modification features at one or two scans. The 1064 nm modification is has tearing and other defects in the modified material. Raman spectra comparison with other polymer (PI) indicated that the PEI-formed low-intensity graphene had fewer structural defects, resulting in improved electrical conductivity properties. |
