Manifestation of quantum size effect in polycrystalline graphene under ultrahigh pressures

The manifestation of the quantum size effect (QSE) was investigated in polycrystalline powdered graphene produced by mechanically exfoliating graphite in water followed by drying (Gf) under various pressing pressures (up to 0.4 GPa). The QSE was characterized by a discontinuous increase in physical properties (thermal and temperature conductivity), measured using the laser flash analysis (LFA) method and differential scanning calorimetry (DSC). Non-contact surface topography measurements of Gf were performed using optical profilometry (OP).