Evidence for Charge Transfer at the Interface between Hybrid Phosphomolybdate and Epitaxial Graphene.
The interfacing of polyoxometalates and graphene can be considered to be an innovative way to generate hybrid structures that take advantage of the properties of both components. Polyoxometalates are redox-sensitive and photosensitive compounds with high temperature stability (up to 400 °C for some), showing tunable properties depending on the metal incorporated inside the complex. Graphene has a unique electronic band structure combined with good material properties for electrical and optical applications. The spontaneous, rather than electrochemical, functionalization of epitaxial graphene on SiC with Keggin phosphomolybdate derivative TBA3[PMo11O39{Sn(C6H4)C≡C(C6H4)N2}] (named K(Mo)Sn[N2(+)]) bearing a phenyl diazonium unit is investigated. Graphene decoration is evidenced by means of AFM, Raman, XPS, and cyclic voltammetry, indicating a successful immobilization of the polyoxomolybdate. The covalent bonding of the polyoxometalate to the graphene substrate can be deduced from the appearance of a D band in the Raman spectra and from the loss of mobility in the electrical conduction. High-resolution XPS spectra reveal an electron transfer from the graphene to the Mo complex. The comparison of charge-carrier density measurements before and after grafting supports the p-type doping effect, which is further evidenced by work function UPS measurements.
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-PHELIQS, 17 rue des Martyrs, F-38054 Grenoble, France.
Loïc
L
Huder
Sorbonne Universités, UPMC Univ. Paris 06, CNRS UMR 8232, Institut Parisien de Chimie Moléculaire, Université Pierre et Marie Curie , 4 Place Jussieu, Case 42, F-75252 Paris cedex 05, France.
Corentin
C
Rinfray
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA-LETI, MINATEC, 17 rue des Martyrs, F-38054 Grenoble, France.
Denis
D
Rouchon
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA-LITEN, MINATEC, 17 rue des Martyrs, F-38054 Grenoble, France.
Anass
A
Benayad
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-SyMMES, 17 rue des Martyrs, F-38054 Grenoble, France.
Mira
M
Baraket
Sorbonne Universités, UPMC Univ. Paris 06, CNRS UMR 8232, Institut Parisien de Chimie Moléculaire, Université Pierre et Marie Curie , 4 Place Jussieu, Case 42, F-75252 Paris cedex 05, France.
Guillaume
G
Izzet
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-PHELIQS, 17 rue des Martyrs, F-38054 Grenoble, France.
Felipe
F
Lipp-Bregolin
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-PHELIQS, 17 rue des Martyrs, F-38054 Grenoble, France.
Gérard
G
Lapertot
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-SyMMES, 17 rue des Martyrs, F-38054 Grenoble, France.
Lionel
L
Dubois
Sorbonne Universités, UPMC Univ. Paris 06, CNRS UMR 8232, Institut Parisien de Chimie Moléculaire, Université Pierre et Marie Curie , 4 Place Jussieu, Case 42, F-75252 Paris cedex 05, France.
Anna
A
Proust
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-PHELIQS, 17 rue des Martyrs, F-38054 Grenoble, France.
Louis
L
Jansen
Université Grenoble Alpes , F-38000 Grenoble, France.|CEA, INAC-SyMMES, 17 rue des Martyrs, F-38054 Grenoble, France.
Florence
F
Duclairoir