Decoding structural characteristics of fluorinated graphene via Computer-Aided spectroscopic analysis

Abstract

Fluorographene, a monolayer form of carbon monofluoride, is a fluorinated graphene derivative with intriguing properties and serves as a crucial precursor for synthesizing various graphene-based materials. Understanding its structural and chemical characteristics is essential for harnessing its potential, yet many aspects of its structure remain far from fully understood. Common spectroscopic methods such as infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) face challenges in precisely assigning measured binding energies and IR signals to specific atomic configurations. To address these ambiguities, we combined ab initio density functional theory calculations with experimental approaches to model spectroscopic signatures of various conformations and structural defects in fluorographene. Additionally, we investigated the structures of partially fluorinated graphene derivatives, C₂F and C₄F. Our theoretical insights guided the structural interpretation of an in-depth characterization of two typical commercially available graphite fluoride samples using multiple techniques, including Fourier-transformed IR, XPS with Ar⁺ ion beam etching, electron paramagnetic resonance, and nuclear magnetic resonance. Our findings highlight the valuable role of low-frequency IR spectroscopy and establish a foundation for identifying key structural features through a combination of theoretical calculations and spectroscopic experiments, applicable not only to fluorographene and fluorinated graphite but also in exploring structural characteristics of other two-dimensional and layered materials.