Altering interfacial properties through the integration of C₆₀ into ZnO ceramic via cold sintering process

A lot of nanocomposites containing C₆₀ have been developed to enable various application opportunities. However, it seems impossible to incorporate C₆₀ into ceramics without destroying the C₆₀ molecules, because ceramics are typically sintered at high temperatures that could result in the chemical reaction of C₆₀. Herein, we report the successful integration of C₆₀ with ZnO using cold sintering process. (1-x)ZnO-xC₆₀ composites with x ranging from 0 to 5 wt% are densified into monolithic structures with relative densities over 95%. Clear C₆₀ molecules are observed in the cold sintered composites, and thin C₆₀ layers with less than 10 nm are located at the ZnO grain boundaries. With C₆₀ altering the interfacial structures of ZnO ceramics, the electrical properties are improved significantly, especially, the breakdown electric field at 1 mA cm⁻² is enhanced from ∼80 V mm⁻¹ to ∼2100 V mm⁻¹. The FEM analysis indicates that the current density at the interfaces of ZnO and C₆₀ is higher than other regions. This work thus indicates that cold sintering process provides a promising pathway to design new types of functional materials through the integration of C₆₀ and ceramics.