Chemical Analysis of Commercial Functionalized Graphene Nanoplatelets along the Production Process with Raman...

Commercial applications increasingly rely on functionalized graphene nanoplatelets (GNPs) supplied as powders, aqueous suspensions, and printable inks, yet their process-structure-property relationships across the production chain remain to be fully mapped. Here we apply a correlative Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS) workflow to nine independent industrial graphene batches spanning three surface chemistries, raw (R), fluorinated (F), and nitrogen-functionalized (N), in all three physical forms which are powders, suspensions, and inks. Raman mapping (with a 532 nm excitation laser) showed that I _2D/I _G is highest for N-samples and lowest for R-ink. A 2D-vs-G correlation places all samples on a trajectory parallel to the pure-doping vector, which can correlate to holes in the graphene lattice. The mean point-defect spacing is L _D = 8.4-10.0 nm. High-resolution XPS resolves the accompanying chemical changes: F-powder exhibits distinct C-F (289 eV), C-F₂ (292 eV), and C-F₃ (293 eV) components and loses roughly half its F content upon dispersion in deionized water or ink formulation; inks of all chemistries show a pronounced O-CO peak near 289-290 eV originated from the ink compounds. N-functionalized samples showed a prominent C-N (285.5 eV) only for the ink formulated N-functionalized sample. This study establishes a process-aware blueprint linking the functionalization route and formulation step to lattice disorder and surface chemistry, offering transferable quality-control metrics for graphene supply chains in industrial products/applications such as coatings, storage devices, and printed electronics.