Direct observation of spatially heterogeneous single-layer graphene oxide reduction kinetics.
Graphene oxide (GO) is an important precursor in the production of chemically derived graphene. During reduction, GO's electrical conductivity and band gap change gradually. Doping and chemical functionalization are also possible, illustrating GO's immense potential in creating functional devices through control of its local hybridization. Here we show that laser-induced photolysis controllably reduces individual single-layer GO sheets. The reaction can be followed in real time through sizable decreases in GO's photoluminescence efficiency along with spectral blueshifts. As-produced reduced graphene oxide (rGO) sheets undergo additional photolysis, characterized by dramatic emission enhancements and spectral redshifts. Both GO's reduction and subsequent conversion to photobrightened rGO are captured through movies of their photoluminescence kinetics. Rate maps illustrate sizable spatial and temporal heterogeneities in sp(2) domain growth and reveal how reduction "flows" across GO and rGO sheets. The observed heterogeneous reduction kinetics provides mechanistic insight into GO's conversion to chemically derived graphene and highlights opportunities for overcoming its dynamic, chemical disorder.
Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Matthew P
MP
McDonald
Ahmed
A
Eltom
Felix
F
Vietmeyer
Janak
J
Thapa
Yurii V
YV
Morozov
Denis A
DA
Sokolov
Jose H
JH
Hodak
Kizhanipuram
K
Vinodgopal
Prashant V
PV
Kamat
Masaru
M
Kuno
D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry*; D007700:Kinetics; D009930:Organic Chemicals / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010782:Photolysis
D009930:Organic Chemicals; D010087:Oxides; D006108:Graphite