Laser Light Induced Transformation of Molybdenum Disulphide-Based Nanoplatelet Arrays

Abstract

One-pot hydrothermal synthesis of MoS2 nanoplatelet arrays on various substrates is perhaps the most promising approach to fabricate efficient electrocatalysts for hydrogen evolution reaction. However, the main challenges in this synthesis remain the purity and crystallinity of MoS2. In this study, we show for the first time that irradiation of amorphous, defect-rich MoS2 nanoplatelets with a green nanosecond laser at a proper irradiation dose, ca ≤0.35 J cm−2, can significantly improve the crystallinity and purity of MoS2 nanoplatelets. The effect was confirmed by Raman spectroscopy investigations demonstrating a surprising intensity increase of the A1g and modes after the laser irradiation. Further increase of irradiation energy, however, resulted in the photocorrosion and destruction of MoS2 nanoplatelets. The variation of A1g and Raman mode intensities ratio depending on the green light irradiation dose was also presented and is discussed below.

Structural Ordering of Molybdenum Disulfide Studied via Reactive Molecular Dynamics Simulations

“…On the other hand, from the values in Tab. 1 one can notice that for having a characteristic time in the order of seconds or minutes, the temperature needs to be raised to 900-1000 K. This range is compatible with the temperatures that can be reached at the contact during a tribological measurements [66][67][68] or in experiments where samples are irradiated with laser beams 40,44,45,69 and therefore, under the assumptions made within the present treatment, our results can provide a framework for the interpretation of the experimental findings.…”

Stable Sulfur‐Intercalated 1T′ MoS2 on Graphitic Nanoribbons as Hydrogen Evolution Electrocatalyst

“…It was noted that sample oxidation was easily achieved under strong laser radiation at ambient conditions resulting in the appearance of three vibrational modes at 240, 336, and 377 cm −1 (Figure S10, Supporting Information), similar to J 2 , J 3 , and E 2g seen on 1T and 2H MoS 2 . However, these modes were accompanied by an intense vibrational mode at 820 cm −1 characteristic of α‐MoO 3 . Therefore, it was recommended to routinely perform a wide scan to verify the presence of MoS 2 .…”

Exfoliation of Transition Metal Dichalcogenides by a High-Power Femtosecond Laser

“…Also, the sample is not exfoliated or easily damaged in the sample depending on the laser power. In the case of TMD materials, the pulse laser has been used to fabricate electro catalysts, quantum dots, and MoO x materials 19 – 21 . However, there are several reports that NS laser irradiation can generate lots of defects because of heat dissipation.…”