Laser-induced methods for obtaining carbon nanomaterials in liquid nitrogen under femtosecond radiation

Abstract

The paper presents the experimental results of nanostructures formation under the influence of femtosecond laser radiation on carbon samples at liquid nitrogen temperatures. Two femtosecond laser systems were used to study the processes of laser action on highly oriented pyrolytic graphite and glassy carbon samples in liquid nitrogen: titanium-sapphire laser system with wavelength 800 nm, pulse duration 50 fs, energy 1 mJ, and repetition frequency of 1 kHz; ytterbium laser system with wavelength 1030 nm, pulse duration 280 fs, energy 150 µJ, and repetition frequency of 10 kHz. Cryostats, including those with the possibility of observing the laser action process, were collected for the experiments. As a result of laser action on the surface of the processed carbon samples, sheets of exfoliated graphene of various sizes and shapes (sheets, tapes, crumpled graphene), as well as nanostructures in the form of nanopeaks, were obtained. The mechanisms of graphene exfoliation under femtosecond laser action in liquid nitrogen, consisting in intercalation and further heating of nitrogen molecules in the interplanar space of graphite, were proposed. The possibilities of further research and development of technologies for graphene formation using laser radiation are presented.

Synthesis, Characterization, and Typical Application of Nitrogen‐Doped MoS2 Nanosheets Based on Pulsed Laser Ablation in Liquid Nitrogen

“…Several parameters, including cryogenic temperature, density, molecular structure, and hightemperature gradient, affect the MoS 2 synthesis. [35,83,84] Figure 11a displays the MoS 2 target cooling during immersion in LN 2 . The lattice vibrations of the target material calm down notably at such cryogenic temperatures.…”

“…Consequently, LN 2 as a 2D cryo-fluid enters the interlayer spacing of the MoS 2 target for intercalation. [35,83,84] Figure 11b depicts the laser beam focused on the interface of the MoS 2 target and LN 2 . However, the exfoliation takes place at the same time in beneath layers to synthesize MoS 2 NSs according to the top-down process relying on the sudden evaporation and expansion of LN 2 to gas according to Figure 11c.…”

Electrophysics of carbon 1D structures obtained in a laser experiment: models and demonstration

“…In this case, for example, for femtosecond light pulses, certain nonequilibrium phase transitions occur with a nonstationary formation of structures of various dimensionality [8,10,18,27,28].…”

Electrophysics of carbon 1D structures obtained in a laser experiment: models and demonstration

“…£ ÒÑÔÎÇAEÐÇÏ ÔÎÖÚÂÇ, ÐÂÒÓËÏÇÓ, AEÎâ ×ÇÏÕÑÔÇÍÖÐAEÐÞØ ÔÄÇÕÑÄÞØ ËÏÒÖÎßÔÑÄ ÒÓÑËÔØÑAEâÕ ÐÇÓÂÄÐÑÄÇÔÐÞÇ ×ÂÊÑÄÞÇ ÒÇÓÇØÑAEÞ ÑÒÓÇAEÇÎÈÐÐÑÅÑ ÕËÒÂ Ô ÐÇÔÕÂÙËÑÐÂÓÐÞÏ ÒÓÑÙÇÔ-ÔÑÏ ÑÃÓÂÊÑÄÂÐËâ ÔÕÓÖÍÕÖÓ ÓÂÊÐÑÌ ÓÂÊÏÇÓÐÑÔÕË [8,10,18,27,28].…”