Graphene Oxide–Phosphor Hybrid Nanoscrolls with High Luminescent Quantum Yield: Synthesis, Structural, and X-ray Absorption Studies

Highly luminescent graphene oxide (GO)–phosphor hybrid thin films with a maximum quantum yield of 9.6% were synthesized via a simple chemical method. An intense luminescence emission peak at 537 nm and a broad emission peak at 400 nm were observed from the GO–phosphor hybrid films. The maximum quantum yield of the emissions from the hybrid films was found to be 9.6%, which is 48 times higher than that of pristine GO films. The GO–phosphor hybrids were prepared via spin-coating and subsequent postannealing of the films, resulting in scrolling of the GO sheets. The resulting GO nanoscrolls exhibited a length of ∼2 μm with nanoscale interior cavities. Transmission electron microscopy and selected-area electron diffraction analyses revealed that the lattice structure of the tubular scrolls is similar to that of carbon nanotubes. While pristine GO films are p-type, in the GO–phosphor hybrids, the Fermi level shifted upward and fell between the HOMO–LUMO gap due to phosphor attachment via C–N bonding. The highl...