Pump-Probe X-ray Photoemission Spectroscopy of Free-Standing Graphane

Free-standing nanoporous graphene was hydrogenated at about 60 at.% H uptake, as determined by the emerging of sp3 bonding component in C 1s core level investigated high-resolution X-ray photoelectron spectroscopy (XPS). Fully unsupported graphane XPS under optical excitation 2.4 eV. At a laser fluence 1.6 mJ/cm2, partial irreversible dehydrogenation observed, which could be attributed either to local temperature increase or photo-induced softening H-to-C stretching mode. The sub-ns dynamics energy shift and peak broadening revealed two different decay constants: 210 ps 130 ps, respectively, former associated with photovoltage latter thermal heating on time scale comparable synchrotron temporal resolution.