Enhancement of Interfacial Charge Transfer of TiO₂/Graphene with Doped Ca²⁺ for Improving Electrical Conductivity

Abstract

Imparting surface coatings with conductivity is an effective way to prevent fire and explosion caused by electrostatic discharge. TiO₂ is a commonly used paint; however, intrinsic TiO₂ has poor electrical conductivity. Herein, we develop a method to make TiO₂ coating highly conductive by doping Ca²⁺ into the TiO₂ lattice based on the introduction of graphene. It is demonstrated that doping Ca²⁺ increases the carrier density of TiO₂ and its morphology changes from a sphere to a spindle shape, which increases the interfacial contact area between TiO₂ and graphene. Therefore, resistivity can be greatly decreased due to the construction of fast charge transport pathways from TiO₂ to graphene, resulting from an increase in the speed of interfacial charge transfer. In addition, the electronic properties of the samples are also studied through first-principles calculations before and after Ca²⁺ doping. The result of the theoretical analysis is in agreement with that of experiments. Thus, the lowest resistivity of Ca²⁺-TiO₂/graphene can reach 0.004 Ω cm. Consequently, the feature of superior conductivity of the Ca²⁺-TiO₂/graphene composite endows it with practical application potential in the field of antistatic coating.