Manifestations of Laser-Induced Graphene under Ultraviolet Irradiation of Polyimide with Varied Optical Fluence

Abstract

In this work, we put forward a rigorous study on ultraviolet (355-nm) laser irradiation of polyimide for the realization of high-quality laser-induced graphene (LIG) with micron-scale features. High-quality material and micron-scale features are desirable—but often at odds—given that small features demand tightly focused beam spots, with a predisposition to ablation. As such, we investigate the synthesis of LIG by correlating the material characteristics, as gleaned from scanning electron microscopy and Raman spectroscopy, to the incident optical fluence, as a measure of applied optical energy per unit area. The study reveals that high-quality LIG, with ratios of Raman 2D-to-G peak heights approaching 0.7, can be synthesized with micron-scale features, down to 18 ± 2 μm, given suitable attention to the optical fluence. Optimal characteristics are seen at optical fluences between 40 and 50 J/cm2, which promote graphenization and minimize ablation. It is hoped that these findings will lay a foundation for the application of LIG in future integrated technologies.

Improvements in properties of polybenzoxazine-based laser-induced graphene (LIG) by alloying with polyimide and modeling of production process

“…The values of I D I G and I 2D I G recorded with the 50%poly(Ph-dde) : 50%polyimide-LIG produced under the optimum conditions compares favourably with the values recorded with LIG produced on a polyimidebased substrate. [33][34][35][36] Furthermore, an L a of 66.3 nm was recorded for the optimum conditions, which shows that the 50% poly(Ph-dde) : 50%polyimide-LIG produced has larger pore spaces compared to the pore spaces of the 50%poly(Ph-dde) : 50%polyimide-LIG (Table 3) produced with power, speed, pulse per inch (PPI), and focus parameters set at 4.5 W, 18 cm s −1 , 1000 and 1.5 inches, respectively. Interestingly, the zoomed-in SEM image of the 50%poly(Ph-dde) : 50%polyimide-LIG produced under the optimum conditions (Fig.…”

Bioderived Laser-Induced Graphene for Sensors and Supercapacitors

“…This kind of pretreatment is truly relevant for bioderived precursors, typically having poorer thermal and fire stability with respect to high-performance synthetic polymers. Laser features. A first important feature is the type/emission wavelength λ. UV, ,− visible. ,,− and IR ,, laser sources have been successfully tested, enabling us to choose between photochemical or photothermal routes for the pyrolysis process. , Also, the pulse width t (continuous, picosecond, and femtosecond) ,, of the laser scribing profoundly affects the LIG formation. Fluence H of the laser scribing . Fluence H is defined as the energy per surface area and it is an important parameter, which also depends on the focusing conditions (4) of the laser and on the number of consecutive multiple laserings on the same spot. Scribing atmosphere.…”

“…Laser features. A first important feature is the type/emission wavelength λ. UV, ,− visible. ,,− and IR ,, laser sources have been successfully tested, enabling us to choose between photochemical or photothermal routes for the pyrolysis process. , Also, the pulse width t (continuous, picosecond, and femtosecond) ,, of the laser scribing profoundly affects the LIG formation.…”

Surface Morphological Growth Characteristics of Laser-Induced Graphene with UV Pulsed Laser and Sensor Applications

“…The effect of laser processing on LIG generation is largely defined in two ways: the photochemical process, which involves the removal of functional groups including oxygen, and the reorganization of the lattice from sp3 to sp2, which is a photothermal reaction. − Shin et al mentioned that photothermal and photochemical reactions occur simultaneously, and the laser ablation of polyimide is dominated by the photochemical effect at low laser fluence, whereas it is dominated by the photothermal effect at high laser fluence . Wang et al reported that depending on the wavelength of the laser, the photochemical or photothermal effect appears differently, and the composition of the LIG also changes …”