Seed-mediated synthesis of monodispersed Cu₂O nanocubes with five different size ranges from 40 to 420 nm

We report the high yield growth of monodispersed Cu₂O nanocubes with approximate average sizes of 40, 65, 100, 230, and 420 nm using a seed-mediated synthesis approach in aqueous solution, The nanocubes are formed in 2 hours at room temperature. The standard deviation of the nanocube sizes in each sample is below 10%. Structural analysis revealed that these nanocubes have six {100} faces, and possess truncated {110} edges and {111} corners. The combination of sodium dodecyl sulfate (SDS) and CuSO₄ was found to be critical to the formation of structurally well-defined Cu₂O nanocubes. The nanocubes presumably were formed through the controlled aggregation of Cu₂O seed particles and then surface reconstruction under the influence of SDS capping surfactant and sulfate ions to yield this truncated cubic structure. Optical characterization showed that nanocubes smaller than 100 nm absorb at -490 nm, while nanocubes larger than 200 nm display an absorption band at 515-525 nm. Additional absorption feature was observed in the red and near-infrared regions for the larger Cu₂O nanocubes due to the light scattering effect. The investigation of the application of these nanocubes for the photodegradation of rhodamine B revealed the {111} crystal surfaces as the active surfaces responsible for the photocatalytic activity of Cu₂O nanostructures. This simple and rapid synthesis of monodispersed Cu₂O nanocubes should allow further examination of their various properties as a function of nanocrystal sizes.