Microrods based on nanocubes of Prussian blue

Using a facile dynamic vacuum evaporation method, a novel microrod with diameters of ca. 1–2 μm and lengths of up to 80 μm has been constructed using uniform Prussian blue (PB) nanocubes as the building blocks. The PB nanocubes are arranged fairly orderly in the rod-like superstructures. The assembled architecture can be transformed from one-dimensional microrods to two-dimensional layers via a fish-bone-like structure by tuning the evaporation rate. The formation of the PB superstructures follows an oriented-attachment mechanism and this provides a simple approach to fabricate hierarchical nanostructures and self-assembled superstructures using nanosized building blocks. Magnetic studies indicate that the PB microrods have a Curie temperature (T_c) of 4.9 K and a coercivity of ca. 26 Oe at 1.8 K. The photoluminescence (PL) spectra of the PB microrods and the dispersed nanocubes show an UV emission band at 358 and 367 nm respectively, suggesting an interesting assembly effect.