Gelatin-mediated hydrothermal synthesis of apple-like LaCO3OH hierarchical nanostructures and tunable white-light emission

A fabrication of uniform apple-like LaCO3OH hierarchical nanostructures was achieved by a facile hydrothermal route using gelatin as the reactant and structure-directing agent. The hierarchical nanostructures with diameters of 2-5 mu m are built from numerous nanoplatelets with thicknesses of 10-20 nm and lengths of 30-80 nm. Influential factors such as reaction time, reaction temperature, dosage of gelatin and potassium hydroxide were systematically investigated. A dipole-field-driven process was suggested for the formation of the apple-like LaCO3OH hierarchical nanostructures. Strong emission centring at 432 nm was realized in the apple-like LaCO3OH hierarchical nanostructures on excitation with 365 nm ultraviolet light. It turns out that it is easy to tune the luminescent characteristics of the LaCO3OH hierarchical nanostructures in a wide spectral range by simply varying excitation lines or doping concentration of Eu3+ and Tb3+. Particularly, white light emission can be obtained in the Eu3+ and Tb3+ codoped LaCO3OH hierarchical nanostructures on excitation in a wide ultraviolet band.