A general chemical conversion route to synthesize various ZnO-based core/shell structures

Core/shell structures often exhibit improved physical and chemical properties. Developing a relatively general, facile, and low temperature synthetic approach for semiconductor core/shell structures with complex compositions is still a particularly challenging work. Here we report a general chemical conversion route to prepare high quality ZnO-based core/shell (ZnO/ZnS, ZnO/Ag2S, and ZnO/CuS) microspheres using inexpensive and commercially available reagents. The key to the success of our strategy lies in the use of reactive templates to realize the synthesis of various ZnO-based core/shell structures. The yielded core/shell nanostructures were confirmed by transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction measurements. Photoluminescence of the ZnO/ZnS core/shell microspheres exhibits a distinct enhancement compared with that of the uncoated ZnO microspheres, showing potential application in optoelectronic devices such as ultraviolet light-emitting diodes and diode lasers. The present chemical conversion approach is expected to be employed in a broad range of applications to fabricate innovative semiconductor core/shell structures with different compositions and shapes for unique properties.