Observing High-Pressure Chemistry in Graphene Bubbles

Using IR spectroscopy, high-pressure reactions of molecules were observed in liquids entrapped by graphene nanobubbles formed at the graphene-diamond interface. Nanobubbles formed on graphene as a result of thermally induced bonding of its edges with diamond are highly impermeable, thus providing a good sealing of solvents within. Owing to the optical transparency of graphene and diamond, high-pressure chemical reactions within the bubbles can be probed with vibrational spectroscopy. By monitoring the conformational changes of pressure-sensitive molecules, the pressure within the nanobubble can be calibrated as a function of temperature and it is about 1GPa at 600K. The polymerization of buckministerfullerene (C-60), which is symmetrically forbidden under ambient conditions, is observed to proceed in well-defined stages in the pressurized nanobubbles.