Our 2D-PRINTABLE partners from UKa, TCD, VSCHT and EPFL have published a new article titled “Assessing quality and purity of MoS₂ nanosheets by diffuse reflectance IR spectroscopy” in 2D Materials.
The study demonstrates the use of diffuse reflectance infrared (IR) Fourier transform spectroscopy to analyze freeze-dried 2D MoS₂ nanosheets produced through various exfoliation methods.
First-principles calculations predicted IR spectral shifts corresponding to nanosheet thickness in the few-layer regime (<10 layers), which were confirmed experimentally. The authors also showed that centrifugation effectively removes small-molecule surfactants used in liquid-phase exfoliation, while residues persist in MoS₂ nanosheets obtained via sonication in NMP or electrochemical exfoliation.
This work provides a useful protocol to improve washing steps or monitor chemical modifications, and highlights that IR-active vibrational modes – accurately predicted from first principles – can serve as a reliable tool to determine the number of layers in 2D materials.
Congratulations to our partners on this achievement.
