1. Chemical Modification ( 化学修飾 ) of Graphene Tobe Lab. M1 Kosuke Hada 1

2. Contents 2 Graphene Self-assembly of Molecules My Work Graphene Self-assembly of Molecules My Work

3. Graphene 3 Graphite

4. Graphene 4 Graphene was isolated by using adhesive tape. Novoselov and Geim won the Nobel Prize in 2010. Novoselov, K. S. et al. Science 2004, 306, 666-669.

5. Graphene 5 Zboril, R. et al. Chem. Rev. 2012, 112, 6156−6214. Properties of Graphene ・ Strength ・ Zero Band Gap ・ Ultrahigh Carrier Mobility New Material Touch Screens Sensor Solar Cell

6. 6 Chemical Modification ( 化学修飾 ) of Graphene ・ Changing double bonding of graphene to single bonding double bonding : strong bonding single bonding : weak bonding Carbon having double bonding : conductive Carbon having no double bonding : non-conductive We can control strength and conductivity of graphene ・ Adding molecule having useful properties to graphene We can add useful property to graphene

7. Graphene Oxide 酸化グラフェン R = Cl, NO 2, OCH 3, Br 1. N 2 H 4 ・ H 2 O, pH 10 80 ゜ C, 24 h 2., rt, 1 h Example of Chemical Modification of Graphene 7 Tour, J. M. et al. J. Am. Chem. Soc. 2008, 130, 16201-16206. ←Photographs of supernatant N,N′- dimethylformamide (DMF) solutions ( 上澄み ) obtained from dispersions of (a) graphene and (b) R = Br, (c) R = Cl, (d) R = NO 2, and (e) R = OCH 3 after centrifugation ( 遠心分離 ) for 15 min at 3200 rpm Graphene modified can be dispersed ( 溶ける ) in polar solvent such as N,N′- dimethylformamide (DMF)

8. Functionalization With Diazirine of Graphene TEM Image of Functionalized Graphene Workentin, M. S. et al. Langmuir 2011, 27, 13261–13268. 8 Carbene Addition ( 付加反応 ) ( 高反応性 )

9. 9 Problem of Chemical Modification of Graphene Non-regular modification We can’t precisely control the property Regular modification is needed to control precisely the property

10. Contents 10 Graphene Self-assembly of Molecules My Work

11. Construction of Nano Structure on Surfaces = molecules = substrate = photoresist = substrate light Top-down approach (photolithography) Bottom-up approach (molecular self-assembly) Self-assembly About 100 nm scale 1~10 nm scale 11

12. 12 Tunneling current Mechanism of Scanning Tunneling Microscopy (STM)

13. STM 13 Tip Sample electron Tunneling current Tip Sample Small change d (distance) J i (tunneling current) Large change J i = Aexp(-Bd) J i : tunneling current A, B : constant d : distance

14. 14 Lackinger, M.; Griessl, S.; Heckl, W. M.; Hietschold, M.;Flynn, G. W.; Langmuir, 2005, 21, 4984. Example of 2D Molecular Self-assembly STM Image of 2D Molecular Self-assembly at Alkanoic Acids/Graphite Interface

15. STM Image of DBA on Graphite Honeycomb Structure of Dehydrobenzo[12]annulene (DBA) at the Liquid/Graphite Interface = 15 DBA Self-Assembly at the Liquid/Solid Interface

16. Honeycomb Structure of Dehydrobenzo[12]annulene (DBA) at the Liquid/Solid Interface = 16 Van der Waals Force between the Molecules Van der Waals Force between the Molecules and the Solid DBA Self-Assembly at the Liquid/Solid Interface

17. Honeycomb Structure of Dehydrobenzo[12]annulene (DBA) at the Liquid/Graphene Interface = 17 STM Image of DBA on Single-Layer Graphene on Cu DBA

18. Characters of DBA DBA = We can change the size of DBA and holes Holes catch the another molecules Sensor 18

19. Contents 19 Graphene Self-assembly of Molecules My Work

20. Purpose of My Work Chemical stability of diazirine Precursor of carbene Photo-reaction under long wavelength Diazirine Carbene High reactivity Labeling of biomolecules Adding to graphene Carbene

21. Purpose of My Work = 21 Diazirine Graphene Self-Assembly

22. Graphene Purpose of My Work hv 22

23. Purpose of My Work 23 Regular modification We can precisely control the property

24. STM Image of DBA at the Phenyl Octane/Graphite Interface 24 7.2 × 10 -7 mol/L STM Image of DBA 1 on Graphite Solvent : phenyloctane

25. Summary 25 Graphene is considered as a prospective material because of its unique properties. Chemical modification is used to control the properties of graphene and functionalize it Self-assembly by non-covalent interactions is used to construct the ordered structures at the solid surface. A purpose of my work is to establish an unique approach which makes periodic functionalization of graphene possible based on self-assemblies of molecules at the liquid/graphene interface and following the addition to the graphene.