Growth and optical properties of ZnO/MgO core/shell nanoparticles

Octylamine capped ZnO/MgO core/shell nanoparticles with different shell thickness were grown by thermolysis of metal organic precursors. The as-grown nanoparticles and subsequently annealed ones were characterized by X-ray diffractometer, transmission electron microscope, high resolution transmission electron microscope, and Micro Raman spectroscope. ZnMgO alloys and amorphous MgO formed on the surface of the ZnO cores in the as-grown core/shell nanoparticles. MgO crystalline formed after annealing at 430 degrees C for 2 h. ZnO cores have strong UV emission and weak visible emission. Growth of the shells could enhance the intensity of ZnO UV emission by 4.2 times. The thinner shells promote the core luminescence more efficiently than thicker ones. After being annealed in air at high temperatures, UV luminescence intensities of both pure core and core/shell nanoparticles degraded, while the luminescence of the core/shell nanoparticles with thinner shells degraded more obviously.