Low percolation threshold in highly conducting graphene nanoplatelets/glass composite coatings

[EN] Thermal sprayed thick glass coatings with a small percentage of multilayer graphene nanoplatelets (GNP) demonstrate electrical functionality with a quite remarkable low percolation limit (1.18 vol.%). This low critical content and the high electrical conductivity (~40 S m¿1) observed for the in-plane direction are related to the peculiar coating microstructure, formed by the pileup of lamellar amorphous particles decorated by GNP mostly following a surface parallel orientation. The general effective media model fitting to the electrical conductivity data for these coatings suggests a 3D connectivity of graphene and estimates an upper limit conductivity for the GNP of 105 S m¿1. Hall effect shows the n-type behavior intrinsic to the SiO2/graphene interface, and carrier density and mobility rising with the GNP content. In addition, the coatings evidence a very high solar absorptivity that jointly with their high electrical conductivity broadens their potential applications, among others, for electromagnetic interference shielding or as photothermal detector and solar absorber for solar steam generation and water desalination.This work was financed by project MAT2015-67437-R (MINECO/FEDER, UE).Peer reviewe