Robust Amphiphobic Few‐Layer Black Phosphorus Nanosheet with Improved Stability

Abstract

Few‐layer black phosphorus (FL‐BP) has been intensively studied due to its attractive properties and great potential in electronic and optoelectronic applications. However, the intrinsic instability of FL‐BP greatly limits its practical application. In this study, the amphiphobic FL‐BP is achieved by functionalization of 1H,1H,2H,2H‐perfluorooctyltrichlorosilane (PFDTS) on the surface of FL‐BP. The obtained PFDTS coated FL‐BP (FL‐BP/PFDTS) demonstrates enhanced stability, which is not observed during significant degradation for 2 months in high moisture content environment (95% humidity). Particularly, attributing to the surface amphiphobicity, FL‐BP/PFDTS exhibits strong surface water repellency in the presence of oleic acid (as the contaminant), while other passivation coating layers (such as hydrophilic or hydrophobic coating) become hydrophilicity under such conditions. Owing to this advantage, the obtained FL‐BP/PFDTS demonstrates enhanced stability in high moisture content environment for 2 months, even though the surface is contaminated by oil liquid or other organic solvents (such as oleic acid, CH2Cl2, and N‐methyl‐2‐pyrrolidone). The passivation of FL‐BP by amphiphobic coating provides an effective approach for FL‐BP stabilization toward future applications.

Regulating the reactivity of black phosphorus via protective chemistry

“…Bulk BP was prepared and characterized following a methodology highlighted in a previous report (fig. S1, A to C) ( 21 ). BP nanosheets were obtained via the sonication of powdered bulk BP in N , N -dimethylformamide.…”

“…To further address the degradation of both BP and BP/Al 3+ /BDT, we detected the amount of PO 4 3− in BP dispersion and BP/Al 3+ /BDT dispersion by UV-vis [see experimental procedures in the Supplementary Materials and fig. S5 (E and F) for details] ( 21 ). For the initial dispersion, the absorbance intensity of both BP and BP/Al 3+ /BDT at 470 nm is roughly the same ( Fig.…”

“…Atomic force microscopy (AFM) analysis reveals that the thickness of BP is 2.65 ± 0.27 nm, which implies that there are four to six individual phosphorene layers ( fig. S1G) (21). X-ray diffraction (XRD) and Raman spectra demonstrate the same crystal characteristic of BP as its bulk form (fig.…”

Recent Advances in Chemical Functionalization of 2D Black Phosphorous Nanosheets

“…Nevertheless, achieving a long‐term stability of functionalized BPNSs over months or years is currently still challenging. Efficient passivation could be achieved by developing new chemical functionalization strategies, for example, reacting/interacting effectively with the paired electrons on BPNSs using different kinds of functional units . This will largely broaden/enrich the chemistry of BPNSs.…”

Electrochemical Delamination of Ultralarge Few‐Layer Black Phosphorus with a Hydrogen‐Free Intercalation Mechanism

“…bulk BP crystals by breaking the interlayer van der Waals interaction. [26][27][28] Compared to the mechanical exfoliation which show low efficiency and not easy to scale up, the method of sonicating bulk BP crystals in liquid solvents (such as water, [27][28][29][30][31][32] anhydrous acetone, [33] methyl pyrrolidone (NMP), [34] and N,Ndimethylformamide (DMF) [35] ) has been widely used to obtain FL-BP nanoflakes with large quantity, paving the way for scalable production of FL-BP nanoflakes for practical applications. As one of the liquid-phase exfoliation technologies, electrochemical intercalation exfoliation utilizes liquid electrolyte and electrochemical potential to drive structural expansion through the anodic oxidation and cationic intercalation, [36][37][38][39][40][41] which has been widely applied to produce large-scale crystals with minimal lattice disruption, such as graphite, [42][43][44][45] transition-metal dichalcogenides, [46] Bi 2 Te 3 , and BN.…”