Two-dimensional MBenes with ordered metal vacancies for surface-enhanced Raman scattering

Abstract

As an emerging class of two-dimensional (2D) materials, MBenes show enormous potential for optoelectronic applications. However, their use in molecular sensing as surface-enhanced Raman scattering (SERS)-active material is unknown. Herein,...

Two-Dimensional Molybdenum Boride (MBene) Mo4/3B2Tx with Broadband and Termination-Dependent Ultrafast Nonlinear Optical Response

“…These unique ordered metal vacancies result in the appearance of abundant vibration modes in Mo 4/3 B 2 T x . As shown in the Raman spectrum (Figure f), the peaks located at 203.5, 284.9, and 346.9 cm –1 were ascribed to the vibration of B atoms with E 1g , A 1g , and E 1 2g symmetries, respectively . The peaks at 620.2, 820.7, and 984.1 cm –1 were recognized as the vibration of Mo-B and B-B bonds of MoB nanosheets .…”

“…On the one hand, the ordinary M-B layers prefer to form boron oxide in a long-term hydrofluoric acid (HF) etch. , On the other hand, the common MAB phase (the precursor of MBene) contains two layers of Al atoms between the M-B layers, which is difficult to be etched by HF, while the MAB phase with only one layer of Al atoms is thermodynamically metastable and challenging in preparation. , Very recently, by changing the precursor into a more reactive i-MAB phase (ternary laminated boride phases with in-plane chemical ordering) and shortening the HF etching time, Zhou et al obtained individual single-layer Mo 4/3 B 2 T x (T = O, F, OH) MBene with the ordered metal vacancies on their surface. As revealed, Mo 4/3 B 2 T x has shown application prospects in electrochemical hydrogen evolution, , surface-enhanced Raman spectroscopy, ultrafast photonics, and other fields. However, the detailed optical properties of Mo 4/3 B 2 T x MBene and the peculiarities induced by the surface-ordered metallic vacancies have rarely been addressed, which may hinder further development of Mo 4/3 B 2 T x nanosheets.…”

Exploring and Engineering 2D Transition Metal Dichalcogenides toward Ultimate SERS Performance

“…(MBenes), [31] transition-metal dichalcogenides (TMDs), [32][33][34][35][36] metal-organic frameworks, [37] and organic semiconductors, [38][39][40] exhibit promising SERS activity, offering potential solutions to the limitations in noble metal-based SERS systems. Especially, 2D TMDs with layered features (Figure 1) have gained extensive investigations due to their superior stability, ease of fabrication, good biocompatibility, controllable doping, and tunable bandgaps and excitons.…”

Optically Active MXenes in Van der Waals Heterostructures

“…Mo 4/3 B 2 has been demonstrated as a potential surface‐enhanced Raman scattering (SERS) platform, for which stable MBene colloidal dispersions can be easily deposited on silicon. [ 114 ] The resulting Raman enhancement factor (EF) reached 3.88 × 10 6 for detecting rhodamine 6G up to a concentration of 1 × 10 −9 m . However, the detection limit of Mo 4/3 B 2 is still far from realizing a (sub)femtomolar level of detection (10 −15 to 10 −16 m ), as demonstrated for other materials such as NbSe 2 layers.…”