Shangping Wang

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 μm 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.

Shape tuning of ZnO with ammonium molybdate and their morphology-dependent photoluminescence properties

In this work, several nano/microscale structures of ZnO including nanospindles, microbundles, microrods, and nanoflowers have been prepared via a facile template and surfactant-free hydrothermal method mediated with ammonium molybdate. It is found that the morphology of ZnO could be readily tailored by simple variation of the concentration of ammonium molybdate. The effects of the concentration of ammonium molybdate and reaction temperature on the synthesis were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and spectrofluorometer (FL) were used to characterize the products. Results reveal that the photoluminescence (PL) properties of the as-prepared ZnO are strongly dependent on their morphologies.