Graphene sheets prepared through liquid exfoliation of expanded graphite were hybridized with Pd nanoparticles. The impact of these particles on the electronic and physical structure of the graphene is determined through transmission electron microscopy and Raman spectroscopy using 532 and 325 nm excitation wavelengths. Based on the changes to the Raman D and G peaks, insights are provided concerning the deposition mechanism at pristine and defective lattice sites, as well as electronic scattering. These data are compared to ab initio band structure computations. For purposes of the model, the graphene/Pd hybrid was approximated by a charged graphene sheet. The resulting structure exhibited π–π∗ expansion approaching the Γ point of the Brillouin zone which was validated by tracking the Raman D band dispersion.
This paper was originally published in Carbon 68, 687–694.
Researchers have turned Raman spectroscopy into a scientific ‘ruler’ to understand how 2D materials expand on exposure to heat.