Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy

doi:10.1038/srep15439

機構典藏 > College of Sciences > Graduate Institute & Department of Physics > Journal Article > Item 987654321/107093

Please use this identifier to cite or link to this item: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/107093

Title:	Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy
Authors:	Wang, Y.F.;Singh, S.B.;Limaye, M.V.;Shao, Y.C.;Hsieh, S.H.;Chen, L.Y.;Hsueh, H.C.;Wang, H.T.;Chiou, J.W.;Yeh, Y.C.;Chen, C.W.;Chen, C.H.;Ray, S.C.;Wang, J.;Pong, W.F.;Takagi, Y.;Ohigashi, T.;Yokoyama, T.;Kosugi, N.
Date:	2015-10-20
Issue Date:	2016-08-15
Publisher:	Springer Nature
Abstract:	This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.
Relation:	Scientific Reports 5, pp.15439-15451
DOI:	10.1038/srep15439
Appears in Collections:	[Graduate Institute & Department of Physics] Journal Article

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