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[[Vol. 10]In Situ Bandgap Tuning of Graphene Oxide Achieved by Electrochemical Bias_ WPI-MANA.pdf](https://mdr.nims.go.jp/filesets/3ed02569-450c-463d-85fc-240ce5d70b0f/download)

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International Center for Materials Nanoarchitectonics (WPI-MANA)

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[[Research Highlights Vol.10] In Situ Bandgap Tuning of Graphene Oxide Achieved by Electrochemical Bias](https://mdr.nims.go.jp/datasets/0c2ea0eb-b36c-4ae5-a1a3-613fcbc64dd7)

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2022/04/04 10:25 In Situ Bandgap Tuning of Graphene Oxide Achieved by Electrochemical Bias| MANAhttps://www.nims.go.jp/mana/research/highlights/vol10.html 1/2Previous  Index  NextResearch Highlights[Vol. 10]In Situ Bandgap Tuning of Graphene Oxide Achieved by Electrochemical Bias30 Jan, 2014The ability to modulate the physical properties of graphene oxide withinelectronic components could have numerous applications in technology.Figure : The newly-fabricated EDL transistor with graphene oxide (GO) made by WPI-MANA researchers allows finetuning of bandgaps in the GO, meaning that conductivity, as well as magnetic and optical properties, can be carefucontrolled.Super-strong graphene oxide (GO) sheets are useful for ultrathin, flexible nano-electronic devices,and display unique properties including photoluminescence and room temperatureferromagnetism. Tsuchiya, Terabe and Aono at Japan's World Premier International Center forMaterials Nanoarchitectonics (WPI-MANA) are developing novel techniques that allow them to finetune the physical properties of GO, such as conductivity, within working components.The conductivity of GO is lower than graphene itself because of disruptions within its bondingstructure. Specifically, the carbon atoms in GO exhibit a blurring of energy levels called sp2 orsp3 hybridizations. In ordinary GO, bonding in the sp2 level is disrupted, and under severedisruption the GO becomes an insulator rather than a conductor. Highly-reduced GO (rGO), withlower oxygen levels, has a near-perfect hexagonal lattice structure with strong bonds and highconductivity.By adjusting the percentages of sp2 and sp3 domains in GO, Terabe and his team have gained theability to fine tune band gaps and therefore control conductivity. Current methods of controllingbandgaps in GO are chemically-based, expensive, and cannot be used within electroniccomponents themselves.https://www.nims.go.jp/mana/research/highlights/vol9.htmlhttps://www.nims.go.jp/mana/research/highlights/index.htmlhttps://www.nims.go.jp/mana/research/highlights/vol11.html2022/04/04 10:25 In Situ Bandgap Tuning of Graphene Oxide Achieved by Electrochemical Bias| MANAhttps://www.nims.go.jp/mana/research/highlights/vol10.html 2/2Now, the team have achieved non-volatile tuning of bandgaps in multi-layered GO within an all-solid-state electric double layer transistor (EDLT). The EDLT comprised GO on a silica glasssubstrate gated by a zirconia proton conductor. The team triggered a reversible electrochemicalreduction and oxidation (redox) reaction at the GO/zirconia interface by applying a dc voltage. Thisin turn caused proton migration from GO through the zirconia (see image). The redox reactioncreated rGO, and caused a fivefold increase in current in the transistor.The rGO retained conductivity for more than one month without further voltage application.Compared with field-effect transistors, the new EDLT uses far less voltage to switch between onand off phases, meaning it is far cheaper to use. This new method for fine tuning conductivitycould lead to control over optical and magnetic properties of components, with far-reachingapplications.Reference"In-situ and Nonvolatile Bandgap Tuning of Multilayer Graphene Oxide in an All-Solid-State ElectricDouble Layer Transistor. Advanced Materials, Early View"Takashi Tsuchiya, Kazuya Terabe, and Masakazu AonoJournal : Advanced Materials 26, 7, 1087-1091, (2014).DOI : 10.1002/adma.201304770AffiliationsInternational Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for MaterialsScience (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, JapanContact informationInternational Center for Materials Nanoarchitectonics(WPI-MANA)National Institute for Materials Science1-1 Namiki, Tsukuba, Ibaraki 305-0044 JapanPhone: +81-29-860-4710E-mail: mana-pr[AT]ml.nims.go.jphttps://samurai.nims.go.jp/profiles/tsuchiya_takashi?locale=enhttps://samurai.nims.go.jp/profiles/terabe_kazuya?locale=enhttps://samurai.nims.go.jp/profiles/aono_masakazu?locale=enhttps://onlinelibrary.wiley.com/doi/10.1002/adma.201304770