Optical absorption bands at -18772 and -18807 cm-1, previously assigned to A2A-X2H electronic origin band transitions of the linear carbon-chain radicals CsH and CsD, respectively, have been reinvestigated. The spectr...Optical absorption bands at -18772 and -18807 cm-1, previously assigned to A2A-X2H electronic origin band transitions of the linear carbon-chain radicals CsH and CsD, respectively, have been reinvestigated. The spectra have been recorded in direct absorption applying cavity ring-down spectroscopy to a supersonically expanding acetylene/helium plasma. The improved spectra allow deducing a l-CsH upper state spin-orbit coupling constant X=-0.7（3） cm-1 and a A2A lifetime of 1.65=0.3 ps.展开更多
Graphene as a two-dimensional material is prone to hydrocarbon contaminations,which can significantly alter its intrinsic electrical properties.Herein,we implement a facile hydrogenation-dehydrogenation strategy to re...Graphene as a two-dimensional material is prone to hydrocarbon contaminations,which can significantly alter its intrinsic electrical properties.Herein,we implement a facile hydrogenation-dehydrogenation strategy to remove hydrocarbon contaminations and preserve the excellent transport properties of monolayer graphene.Using electron microscopy we quantitatively characterized the improved cleanness of hydrogenated graphene compared to untreated samples.In situ spectroscopic investigations revealed that the hydrogenation treatment promoted the adsorption of water at the graphene surface,resulting in a protective layer against the re-deposition of hydrocarbon molecules.Additionally,the further dehydrogenation of hydrogenated graphene rendered a more pristine-like basal plane with improved carrier mobility compared to untreated pristine graphene.Our findings provide a practical post-growth cleaning protocol for graphene with maintained surface cleanness and lattice integrity to systematically carry a range of surface chemistry in the form of a well-performing and reproducible transistor.展开更多
文摘Optical absorption bands at -18772 and -18807 cm-1, previously assigned to A2A-X2H electronic origin band transitions of the linear carbon-chain radicals CsH and CsD, respectively, have been reinvestigated. The spectra have been recorded in direct absorption applying cavity ring-down spectroscopy to a supersonically expanding acetylene/helium plasma. The improved spectra allow deducing a l-CsH upper state spin-orbit coupling constant X=-0.7（3） cm-1 and a A2A lifetime of 1.65=0.3 ps.
基金This work was supported by the Chinese Scholarship Council(201406890016)NWA route‘meten&detecteren’+6 种基金the European Research Council under the European Union’s Seventh Framework Program(FP/2007-2013)/ERC Grant Agreement No.335879 project acronym‘Biographene’the Netherlands Organization for Scientific Research(Vidi 723.013.007)L.Wu and J.P.Hofmann acknowledge funding from The Netherlands Organization for Scientific Research(NWO)cofinancing by Shell Global Solutions International B.V.for the project 13CO2-6E.J.M.H.and V.M.acknowledge support by the Netherlands Center for Multiscale Catalytic Energy Conversion(MCEC)an NWO Gravitation program funded by the Ministry of Education,Culture and Science of the government of the Netherlandsa Vici grant of the NWO.
文摘Graphene as a two-dimensional material is prone to hydrocarbon contaminations,which can significantly alter its intrinsic electrical properties.Herein,we implement a facile hydrogenation-dehydrogenation strategy to remove hydrocarbon contaminations and preserve the excellent transport properties of monolayer graphene.Using electron microscopy we quantitatively characterized the improved cleanness of hydrogenated graphene compared to untreated samples.In situ spectroscopic investigations revealed that the hydrogenation treatment promoted the adsorption of water at the graphene surface,resulting in a protective layer against the re-deposition of hydrocarbon molecules.Additionally,the further dehydrogenation of hydrogenated graphene rendered a more pristine-like basal plane with improved carrier mobility compared to untreated pristine graphene.Our findings provide a practical post-growth cleaning protocol for graphene with maintained surface cleanness and lattice integrity to systematically carry a range of surface chemistry in the form of a well-performing and reproducible transistor.
