ZnS∶Co2+ nanocrystals were prepared in aqueous solution by both one-step and two-step methods.The surface of the prepared ZnS∶Co2+ nanocrystals was modified by mercaptoacetic acid(TGA).The UV-vis absorption spectroscopy was employed as a direct probe to detect the location of Co2+ dopant in ZnS∶Co nanocrystals.The transition of Co2+4T1g(F)→4T1g(P)was observed from the ZnS∶Co2+ nanocrystals derived by the one-step sample,and the Co2+ 4A2(F)→4T1(P)transition was detected from the ZnS∶Co2+ nanocrystals derived by the two-step sample.The results indicate that Co2+ existed on the surface instead of in the lattice of ZnS nanocrystals derived by the one-step method.And for those ZnS∶Co2+ nanocrystals by using the two-step method,Co2+ were co-precipitated in the lattice of ZnS nanocrystals.And additionally,the band gap of the lattice co-precipitated doped ZnS∶Co2+ nanocrystals was narrower than the pure ZnS samples.
Highly(100)-oriented Ba0.8Sr0.2TiO3/LaNiO3 multilayer films have been prepared on different substrates by chemical solution deposition.The microstructure,interface,thickness and morphologies were characterized by XRD,FESEM and AFM techniques,respectively.The results reveal that the multilayer films display satisfied microstructure,clear interface,smooth surface and dense structure,especially,the orientation factor of the 4-period multilayer films can be 0.92 from XRD data and the thickness is about 500nm.The annealing processing plays an important role on the ferroelectric property of highly(100)-oriented multilayer films.
