Layer-by-layer engineering of two-dimensional perovskite nanosheets for tailored microwave dielectrics

We report an approach for constructing ultrathin microwave dielectrics using two-dimensional (2D) perovskite nanosheets (Ca 2 Nb 3 O 10 ). The solution-based layer-by-layer assembly of Ca 2 Nb 3 O 10 nanosheets enables the tailoring of dielectric responses and breakdown voltage in order to realize miniaturized capacitors with improved performances. Multilayer stacked nanosheet films showed a stable dielectric response of up to 10 GHz; the dielectric constant of ∼200 is the highest among high-κ perovskites in the ultrathin region (<30 nm). Moreover, the nanosheet films realized a high capacitance density (∼20 µF/cm 2 ) with a robust thermal stability up to 250 °C. These superior dielectric properties of perovskite nanosheets offer a new solution for high-performance microwave devices.