2014 Fiscal Year Research-status Report
Atomically precise oxidation and alkylation of graphene leading to nanopattern formation on the surface
| Project/Area Number |
25390013
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| Research Institution | Gunma University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | Graphene / Chlorination / Alkylation / STM/STS / XPS / Surface |
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| Outline of Annual Research Achievements |
The present research project is focused on the invention of new chemistry for atomically precise oxidation and alkylation of graphene at nearly monolayer coverage, which can lead to entirely new classes of two-dimensional nanomaterials with vast tunability in chemical, electrical, and optical properties.
After the successful oxidation of graphene in aqueous phase in the first year of this project, I have investigated the alkylation of epitaxial graphene (EG) grown on the SiC substrate in the second year.
As planned initially, I have employed two strategies in order to modify the epitaxial graphene with alkyl groups. (i) Dipping the SiC/graphene sample in the reaction flask where alkyl diazonium ion is synthesized. (ii) Photochemical chlorination of graphene followed by reaction with Grignard’s reagent. Though the first method was not successful, the second two-step chlorination-alkylation procedure is found very effective for alkylation of EG on SiC. STM, Raman and XPS investigations reveal that the first step photo chlorination occurs very selectively on the monolayer regions of EG on SiC leaving the bi- and tri-layer regions clean. Consequently, the alkyl functionalized graphene is observed only in the monolayer graphene regions after the chlorinated EG was treated with CH3MgBr in air-free condition. Both Cl and CH3 are observed to be chemically bonded to the basal plane of the graphene. Based on the results obtained for alkylation of EG on SiC, I have published a paper in J. Phys. Chem. C and presented oral presentation in different international conferences.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
My research project is progressing as planned initially. In the first year of the project, I have investigated oxidation of epitaxial graphene (EG) grown on SiC substrate in aqueous medium and compared the results with the UHV oxidation. In the seocnd year, I have focused on the alkylation of EG on SiC, and alreaddy succeeded the methylation of EG through two-steps chlorination-alkylation processes.
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| Strategy for Future Research Activity |
We have learned from the recent studies that it is very difficult to bind the molecules directly onto pristine graphene and only the radical species can chemisorbed onto graphene. Apart from the photochemical process and thermal cracking of the desired molecules, there are many chemical processes that involve the creation of radical temporarily. For example, an alkyl or aryl radical intermediate generates while synthesizing the Grignard reagent. I plan to investigate if the radical intermediate formed during the chemical synthesis of Grignard reagent can be bind directly onto EG.
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