Gas‐Phase Fluorination of Hexagonal Boron Nitride

Abstract

Hexagonal boron nitride (hBN) has received much attention in recent years as a 2D dielectric material with potential applications ranging from catalysts to electronics. hBN is a stable covalent compound with a planar hexagonal lattice and is relatively unreactive to most chemical environments, making the chemical functionalization of hBN challenging. Here, a simple, scalable strategy to fluorinate hBN using a direct gas‐phase fluorination technique is reported. The nature of fluorine bonding to the hBN lattice and their chemical coordination are described based on various characterization studies and theoretical models. The fluorine functionalized hBN shows a bandgap reduction and displays a semiconducting behavior due to the fluorination process. Additionally, the fluorinated hBN shows significant improvement in its thermal and friction properties, which could be substantial in applications such as lubricants and thermal fluids. Theory and simulations reveal that the enhanced friction properties of fluorinated hBN result from reduced inter‐planar interaction energy by electrostatic repulsion of intercalated fluorine atoms between hBN layers without significant disruption of the in‐plane lattice. This technique paves the way for the fluorination of several other 2D structures for various applications such as magnetism and functional nanoscale electronic devices.

Friction of Ti3C2Tx MXenes

“…As the interlayer coupling is not critical to the performance of Ti 3 C 2 T x lubricity, we instead consider the surface interaction between the MXene termination groups and the diamond-tipped cantilever which slides across the surface in FFM. Surface species have shown significant influence on the frictional properties of 2D materials − and the termination of Ti 3 C 2 T x is well-known to govern the binding energy, work function and electronic properties, polymer reinforcement properties, and many other characteristics of MXenes. As such, we calculate the potential energy surface (PES) of MXenes with exclusively fluorine, oxygen, and hydroxyl termination as shown in Figure .…”

Long-lived fluorinated boron-nitride dots exhibiting room-temperature phosphorescence and high-temperature resistance

“…8, 192.3, and 193.1 eV, which originate from B-N, B-O and B-F, respectively. [38][39][40] The presence of a valid B-F bond can confirm the effective fluorination of the F-BNDs(e). Different from F-BNDs(e), the high resolution B1s spectrum of BNDs(e) only contains two components (Fig.…”

Nanoscale friction characteristics of layered-structure materials in dry and wet environments

“…(E) Optimized geometry of (i) h-BN and (ii) fluorinated h-BN obtained from DFT calculations. The pink, blue, and green atoms are B, N, and F, respectively (Meiyazhagan et al, 2021).…”

“…According to DFT simulations and XRD measurements, F atom bonding to B and N atoms increases the B-N bond length by ~4.5%. Moreover, the repulsive forces that originate from the F atoms between the layers push the fluorinated h-BN layers apart, leading to an increase in the interlayer distance by ~26%, decreasing the interlayer van der Waals energies in the fluorinated h-BN compared to the pristine h-BN (Figure 8E), which explains the lower friction of the modified h-BN layers (Meiyazhagan et al, 2021).…”