Sergeeva Natalia N, Chaika Alexander N, Walls Brian, Murphy Barry E, Walshe Killian, Martin David P, Richards Billy D O, Jose Gin, Fleischer Karsten, Aristov Victor Yu, Molodtsova Olga V, Shvets Igor V, Krasnikov Sergey A
School of Chemistry, University of Leeds, LS2 9JT Leeds, United Kingdom.
Nanotechnology. 2018 Jul 6;29(27):275705. doi: 10.1088/1361-6528/aabf11. Epub 2018 Apr 18.
Herein, we report a simple method for a covalent modification of surface supported graphene with photoactive dyes. Graphene was fabricated on cubic-SiC/Si(001) wafers due to their low cost and suitability for mass-production of continuous graphene fit for electronic applications on millimetre scale. Functionalisation of the graphene surface was carried out in solution via white light induced photochemical generation of phenazine radicals from phenazine diazonium salt. The resulting covalently bonded phenazine-graphene hybrid structure was characterised by scanning tunnelling microscopy (STM) and spectroscopy (STS), Raman spectroscopy and density functional theory (DFT) calculations. It was found that phenazine molecules form an overlayer, which exhibit a short range order with a rectangular unit cell on the graphene surface. DFT calculations based on STM results reveal that molecules are standing up in the overlayer with the maximum coverage of 0.25 molecules per graphene unit cell. Raman spectroscopy and STM results show that the growth is limited to one monolayer of standing molecules. STS reveals that the phenazine-graphene hybrid structure has a band gap of 0.8 eV.
在此，我们报道了一种用光敏染料对表面负载石墨烯进行共价修饰的简单方法。由于立方碳化硅/硅（001）晶圆成本低且适合大规模生产适用于毫米级电子应用的连续石墨烯，因此在其上制备了石墨烯。石墨烯表面的功能化是在溶液中通过白光诱导吩嗪重氮盐产生吩嗪自由基来进行的。通过扫描隧道显微镜（STM）和光谱（STS）、拉曼光谱以及密度泛函理论（DFT）计算对所得的共价键合吩嗪 - 石墨烯杂化结构进行了表征。结果发现，吩嗪分子形成一个覆盖层，该覆盖层在石墨烯表面呈现出具有矩形晶胞的短程有序结构。基于STM结果的DFT计算表明，分子在覆盖层中直立排列，每个石墨烯晶胞的最大覆盖率为0.25个分子。拉曼光谱和STM结果表明，生长仅限于单层直立分子。STS显示，吩嗪 - 石墨烯杂化结构的带隙为0.8电子伏特。
