Global Impact and Balancing Act: Deciphering the Effect of Fluorination on B1s Binding Energies in Fluorinated $h$-BN Nanosheets

Abstract

X-ray photoelectron spectroscopy (XPS) is an important characterization tool in the pursuit of controllable fluorination of two-dimensional hexagonal boron nitride ($h$-BN). However, there is a lack of clear spectral interpretation and seemingly conflicting measurements exist. To discern the structure-spectroscopy relation, we performed a comprehensive first-principles study on the boron 1s edge XPS of fluorinated $h$-BN (F-BN) nanosheets. By gradually introducing 1--6 fluorine atoms into different boron or nitrogen sites, we created various F-BN structures with doping ratios ranging from 1-6\%. Our calculations reveal that fluorines landed at boron or nitrogen sites exert competitive effects on the B1s binding energies (BEs), leading to red or blue shifts in different measurements. Our calculations affirmed the hypothesis that fluorination affects 1s BEs of all borons in the $\pi$-conjugated system, undermining the transferability from $h$-BN to F-BN. Additionally, we observe that BE generally increases with higher fluorine concentration when both borons and nitrogens are non-exclusively fluorinated. These findings provide critical insights into how fluorination affects boron's 1s BEs, contributing to a better understanding of fluorination functionalization processes in $h$-BN and its potential applications in materials science.