The effects of doping and shell thickness on the optical and magnetic properties of Mn/Cu/Fe-doped and Co-doped ZnS nanowires/ZnO quantum dots/SiO_2 heterostructures

摘要

In this paper, we demonstrated the encapsulation of Mn/Cu/Fe-doped and co-doped ZnS nanowires (NWs) and ZnO quantum dots (QDs) with a layer of mesoporous SiO_2 shell for the purpose of integrating dual emission and ferromagnetism property into one common nanostructure at room temperature. Within the ZnS:Mn~(2+)Cu~(2+)Fe~(2+)/Zn0@Si02 nanocomposites, ZnS:Mn~(2+)Cu~(2+)Fe~(2+) NWs and ZnO QDs provided color-tunable visible emission and UV emission, respectively. The color-tunable visible emission in the ZnS:Mn~(2+)Cu~(2+)Fe~(2+) NWs can be obtained by adjusting the concentrations of Mn~(2+), Cu~(2+), and Fe~(2+) ions. The ferromagnetism of the ZnS:Mn~(2+)Cu~(2+)Fe~(2+) NWs was observed around room temperature, the mechanism of which was explained by the super-exchange mechanism. The results of the effect of the ZnO QDs shell thickness on the optical properties of the ZnS:Mn~(2+)/ZnO@SiO_2 nanocomposites showed that the luminescence intensity of the yellow-orange emission and UV emission reached the highest value when the ratio of ZnS:Mn~(2+)/ZnO equaled 1∶5.