Local structural changes in graphene oxide layers induced by silver nanoparticles

Abstract

Structural changes of graphene oxide (GO) in silver/graphene oxide (AGO) nanocomposites are investigated using tip-enhanced Raman scattering (TERS). Because of markedly high spatial resolution of the TERS technique, the measurements of molecular information at specific nano-scaled positions can be achieved by constructing line-profile TERS spectra straight from the center of silver nanoparticles (AgNPs) on GO layers. The results show evidences that AgNPs cause shortening of C–C bonds beneath AgNPs, flattening of GO layers, and critical bending on GO layers. Additionally, a connection of carbon atoms via a C–C network subsequently expands structural changes with a distance of 200–250 nm from the center of AgNPs, even though this distance is larger than the size of AgNPs. The proposed model of GO structural changes unveils new understanding about changes in properties from GO to AGO nanocomposites, which will contribute to a development of advanced nanostructures/nanocomposites in the near future.