Improved charge transfer by Ca2+ modified TiO2/graphene conductive material for enhancing conductivity

In this work, a kind of ternary conductive materials is designed and developed by modifying the TiO2 surface with Ca2+ and combining with graphene. It can be observed from the TEM characterization that TiO2 nanoparticles modified by Ca2+ are dispersed on graphene layer with a tight interfacial contact. The resistivity of Ca2+/TiO2/G is reduced by about 70% compared with the unmodified compounds. The enhanced conductivity can be attributed to the stronger binding strength between Ca2+/TiO2 and G, as well as the formation of additional charge transfer pathways. As a result, the interfacial charge transfer and conductivity can be accelerated. Additionally, the first-principles calculations confirm that the charge transfer does increase through Ca2+ modification. The result demonstrates the importance of the improved interfacial charge transfer for conductivity enhancement and provides new ideas for designing future conductive materials.