A Comparative Study of Laser-Induced Graphene by CO2 Infrared Laser and 355 nm Ultraviolet (UV) Laser.

Liyong Wang,Zhiwen Wang,Hongyu Zheng,Ali Naderi Bakhtiyari

doi:10.3390/mi11121094

Abstract

Laser-induced graphene (LIG) is an emerging technique for producing few-layer graphene or graphene-like material that has recently received increasing attention, due to its unique advantages. Subsequently, a variety of lasers and materials have been used to fabricate LIG using this technique. However, there is a lack of understanding of how different lasers (wavelengths) perform differently in the LIG conversion process. In this study, the produced LIG on polyimide (PI) under a locally water-cooled condition using a 10.6 μm CO2 infrared laser and a 355 nm ultraviolet (UV) laser are compared. The experimental investigations reveal that under the same UV and CO2 laser fluence, the ablation of PI show different results. Surface morphologies with micron-sized and nanometer pores were formed by the UV laser under different laser fluences, whereas micron-sized pores and sheet structure with fewer pores were produced by the CO2 laser. Energy dispersive spectrometry and three-dimensional topography characterization indicate that the photochemical effects were also involved in the LIG conversion with UV laser irradiation. It is also observed through experiments that the photothermal effect contributed to the formation of LIG under both lasers, and the LIG formed on PI substrates by the CO2 laser showed better quality and fewer layers.

Highlights

Graphene has broad applications in sensors, batteries, flexible screens, supercapacitors, and solar cells, owing to its outstanding electrical, thermal, and optical properties [1,2]
Differences in the laser-induced graphene (LIG) formed under the two types of lasers (CO2 infrared laser and 355 nm UV laser) on a locally water-cooled PI substrate were investigated from four aspects, i.e., surface morphology, atomic weight percentages, sheet resistance, and Raman spectrum
The LIG conversion process by both lasers was principally due to the photothermal effect, and the photochemical effect was involved in the UV laser LIG conversion

Summary

Introduction

Graphene has broad applications in sensors, batteries, flexible screens, supercapacitors, and solar cells, owing to its outstanding electrical, thermal, and optical properties [1,2]. The flexibility, controllability, simplicity, and low-cost of laser-induced graphene over conventional methods has rapidly attracted the attention of manufacturers to employ it in the fabrication of high-performance supercapacitors [9,10,11], gas sensors [12,13], strain sensors [14,15], antibacterial devices [16,17], and temperature sensors [18]. After emerging LIG by using a CO2 laser, researchers attempted to apply other types of lasers, including a UV laser, visible laser, and ultra-short pulse laser to generate LIG They evaluated the transition process by investigating the photothermal and the photochemical effects.

Materials and Methods

Morphological Characterization

Conclusions