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 1 GPa at 600 K. The polymerization of buckministerfullerene (C60), which is symmetrically forbidden under ambient conditions, is observed to proceed in well‐defined stages in the pressurized nanobubbles. Graphene anvil: Graphene bubbles can be used as a bench‐top anvil cell for studying high‐pressure chemistry. Pressure‐sensitive molecules that undergo conformational changes were used to probe the internal pressures inside the bubbles, which are 0.5–1 GPa over a temperature window of up to 673 K. The pressure‐induced oligomerization of C60 molecules occurring at distinct P–T windows could be followed using FTIR spectroscopy.