Electrophoretically deposited graphene oxide with modified substrate–suspension interface for tailored field emission response

The interaction between the metallic substrate and precursor suspension in the electrophoretic deposition (EPD) plays a significant role to reduce graphene oxide (GO) from suspension. Possibility of manipulating this interaction to achieve desired functional properties has been studied in this work. From the Pourbaix diagrams for metals, it was identified that modifying pH of the precursor suspension would result in different situations at the interface of the anodically polarized metallic substrate and graphene oxide (GO) aqueous suspensions. Different values of pH ensure that the metal is either passivated or corroding with varying products, in different pH regions. Such a manipulation of the substrate–suspension interface resulted in significantly different characteristics of the deposited reduced graphene oxide (r-GO) film including morphology, structural characteristics and adhesion strength with the substrate. Also, field emission characteristics of the r-GO films deposited in different conditions were studied. The results showed a distinct possibility for optimizing the field emission properties simply through modifying pH of the suspension. The field emission characteristics of deposited (GO) films could be tailored with deposition parameters.