Ambient Stabilization of Few Layer Phosphorene via Noncovalent Functionalization with Surfactants: Systematic 2D NMR Characterization in Aqueous Dispersion

Abstract

Phosphorene suffers from instability under ambient condition, despite its potential to bridge the gap between graphene and two-dimensional (2D) metal chalcogenides. We report effective exfoliation and stabilization of few layer phosphorene (FLP) in the presence of strongly interacting surfactants. Surfactants containing long hydrophobic chain and nonbulky charged headgroups (CTAB) effectively exfoliate and stabilize FLP in water, which is consistent with our density functional theory prediction. Nuclear magnetic resonance measurements are systematically employed to probe the interaction between surfactants and FLP. Retarded diffusion rate measured by 2D DOSY spectroscopy revealed the presence of noncovalently bonded CTAB over phosphorene. 2D NOESY spectroscopy further suggests the interdigitated arrangement of surfactants. Such a tight interaction impedes the ambient degradation rate of phosphorene by 70−80%. This work proposes a new insight into the control over ambient degradation of phosphorene without altering its intrinsic properties.

Chemistry of Phosphorene: Synthesis, Functionalization and Biomedical Applications in an Update Review

“…Several strategies have been considered for the stabilization of phosphorene through functionalization [45], among them there is (i) the introduction of a thin oxidized protecting layer, (ii) heterostructure formation with other 2D materials, (iii) passivation using non-covalent interaction with organic molecules, (iv) encapsulation, (v) covering of the surface with acidic chemical groups, and (vi) including transition metal acceptor fragments. Depending on the kind of interaction (covalent or non-covalent) between the layer surface and the functional groups of the protecting agent, different results are obtained.…”

Noncovalent Functionalization of Pnictogen Surfaces: From Small Molecules to 2D Heterostructures

“…In this study, two different surfactants were applied: cetrimonium bromide (CTAB; Table e) with a long hydrophobic chain and nonbulky charged head groups and tetrabutylammonium hydroxide (TBAOH; Table f) with bulky alkane groups. Few‐layer phosphorene exfoliated and stabilized more efficiently in the presence of CTAB compared with TBAOH . The electrostatic interaction between the cationic head group of CTAB and lone pairs of phosphorene together with dispersion interactions of long linear chain were responsible for the stronger adsorption on the surface of phosphorene …”

“…It is evident that there is a considerable lack of experimental investigations for the functionalization of arsenene, antimonene, and bismuthene. Noncovalent coatings of BP with organic molecules include electrostatic interactions, vdW interactions, charge‐transfer mechanism, and hydrogen bonding …”

“…Recently, an efficient approach to stabilize the surface of few‐layer phosphorene was achieved by surfactant . In this study, two different surfactants were applied: cetrimonium bromide (CTAB; Table e) with a long hydrophobic chain and nonbulky charged head groups and tetrabutylammonium hydroxide (TBAOH; Table f) with bulky alkane groups.…”

Alloying of Alkali Metals with Tellurene

“…For example, unlike 2-D transition metal dichalcogenides and hexagonal boron nitride, Te displays fast charge carrier mobility (~10 3 cm 3 V -1 s -1 ) 19,20 . Further, unlike phosphorene and silicene which are easily oxidized, Te is stable under ambient conditions 21,22,23,24 . Importantly, fewlayered Te can be synthesized using the hydrothermal method with controllable thickness and with a high yield of ~98% 16 .…”