Preparation And Optical Properties Of One Dimensional ZnO Nanorods

One dimensional ZnO nanorods have the advantages of large specific surface area,excellent electron transport properties and good optical properties,which are promising in the fields of solar cells,piezoelectric,catalysis and so on.In this paper,one dimensional ZnO nanorods and coated with ZnS were prepared.The relationship between the phase and morphology of ZnO nanorods and their optical properties were studied.ZnO seed layer had been prepared by the method of sol-gel dip coating method on Si O2 substrate.The seed layer was relatively dense.And the zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and the glycol monomethyl ether(C3H8O2)were the main raw material.ZnO nanords were prepared with hydrothermal method by the seed layer faced down.The core shell structure of ZnO-ZnS nanorods was successfully prepared by the surface curing of ZnO nanorods by thioacetamide.X ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)were used to detect the phase structure and morphology of the ZnO nanorods and the core shell structure of ZnO-ZnS.The optical properties were analyzed by F-280 fluorescence spectrometer.The results show that:1.The ZnO seed layer with wurtzite structure was prepared by sol-gel method.The ZnO seed film is relatively smooth and dense and the minimum grain size is about 20 nm when the sol concentration is 0.25mol/L and the heat treatment temperature is 450 °C.The thickness of each layer of ZnO seed film is about 445 nm.There are two strong luminescence peaks in photoluminescence(PL)spectra of 398 nm and 469 nm.2.One dimensional ZnO nanorods were prepared by two step method.It was more favorable for the growth of ZnO nanorods along the [0001] direction when the concentration of the growth solution was 30mmol/L.The average diameter of this concentration is about 41 nm,the length is about 1130 nm.All samples from PL spectra of ZnO nanorods have two distinct peaks,respectively with 418 nm as the center of the wide and strong UV emission and 467 nm is relatively weak as the center of the blue light emission peak.The luminescent intensity of the samples with the concentration of 30mmol/L was the strongest?3.A layer of ZnS with cubic zinc blende structure was coated on the surface of Z-nO nanorods by hydrothermal reaction.When the concentration of the aqueous solution of thioacetamide is 0.1mol/L,the sample maintains the nanorod array structure,and the surface of the nanorod film is relatively smooth;The surface roughness of the nanorods increases with the increase of sulfide concentration to 0.5mol/L and the surface is coated with a layer of ZnS about 10 nm.A large number of nanoparticles covered the entire nanorod surface when the sulfide concentration continued to increase to 1.0mol/L.The fluorescence spectra have two distinct peaks,respectively with 398 nm as the center of the wide and strong UV emission and 467 nm is relatively weak as the center of the blue light emission peak.The luminescence intensity is the best when the concentration of aqueous solution of thioacetamide is 0.5mol/L.ZnS has some effect on the surface modification of ZnO nanorods,which makes the defect emission of ZnO-ZnS greatly reduced.