Femtosecond Laser Direct Writing of Flexible Electronic Devices: A Mini Review

Abstract

By virtue of its narrow pulse width and high peak power, the femtosecond pulsed laser can achieve high-precision material modification, material additive or subtractive, and other forms of processing. With additional good material adaptability and process compatibility, femtosecond laser-induced application has achieved significant progress in flexible electronics in recent years. These advancements in the femtosecond laser fabrication of flexible electronic devices are comprehensively summarized here. This review first briefly introduces the physical mechanism and characteristics of the femtosecond laser fabrication of various electronic microdevices. It then focuses on effective methods of improving processing efficiency, resolution, and size. It further highlights the typical progress of applications, including flexible energy storage devices, nanogenerators, flexible sensors, and detectors, etc. Finally, it discusses the development tendency of ultrashort pulse laser processing. This review should facilitate the precision manufacturing of flexible electronics using a femtosecond laser.

Synthesis and Unique Behaviors of High-Purity HEA Nanoparticles Using Femtosecond Laser Ablation

“…This rapid interaction leads to intense electron excitation and ionization, significantly impacting the material’s structure without notable lattice heating, while still increasing the energy [ 53 , 54 ]. This sudden energy boost causes some electrons to be ejected from the atom [ 36 ]. As a result [ 54 ], there is a significant imbalance between the positively charged protons and negatively charged electrons, leading to a Coulomb explosion.…”

“…On the other hand, nonthermal melting, a critical phase transition induced by low femtosecond laser fluence, plays a vital role in the joining of nanoparticles. The nonlinear adsorption induced by the femtosecond laser causes a shift in electron density, leading to a slight imbalance that does not reach the threshold of Coulomb explosion or electron ejection [ 36 ]. Instead, this imbalance also weakens the interatomic bonds, creating a quasi-liquid state at the irradiated spots.…”

“…Instead, this imbalance also weakens the interatomic bonds, creating a quasi-liquid state at the irradiated spots. As a result, nanoparticles can merge or fuse at these quasi-liquid zones while maintaining their individual structural integrity and properties [ 36 ]. Significantly, this transition occurs without a corresponding rise in the lattice’s thermal energy, ensuring the nanoparticles’ structural integrity is preserved.…”

“…Femtosecond laser technology presents a potential solution to these challenges [ 27 , 28 ]. Femtosecond lasers, characterized by ultrashort pulse durations, require significantly lower average power compared to conventional continuous wave laser or pulsed lasers with a long pulse width [ 35 , 36 ]. This advancement not only reduces energy consumption but also enhances the control over particle size and distribution, paving the way for more efficient and precise HEA nanoparticle synthesis as well as for many other fields of laser manufacturing and processing [ 37 , 38 ].…”