373 resultados para ZnO nanobelts
Resumo:
室温下用80keVN离子注入ZnO薄膜样品,注量分别为5.01014,5.01015和5.01016ions/cm2,然后用X射线衍射和透射电镜技术对样品的结构特性进行了表征。实验结果表明,由高度(002)择优取向的致密柱状晶构成的薄膜中,注入5.0×1015ions/cm2时,观测到缺陷生成和局域无序化现象,但薄膜总体结构仍保持柱状晶和(002)择优取向;随着注量的增大,晶格常数c和压应力呈增大趋势。对注入N离子对ZnO薄膜结构特性的影响机理进行了简单的讨论。
Resumo:
Using microporous zeolites as host, sub-nanometric ZnO clusters were prepared in the micropores of the host by the incipient wetness impregnation method. A small amount of sub-nanometric ZnO clusters were introduced into the channels of HZSM-5 zeolite, whereas a large quantity of sub-nanometric ZnO clusters can be accommodated in the supercages of HY zeolite and no macrocrystalline ZnO exists on the extra surface of the HY material. The vibrations of the zeolite framework and ZnO were characterized by UV Raman spectroscopy. The optical properties of these ZnO clusters were studied by UV-visible absorption spectroscopy and laser-induced luminescence spectroscopy. It is found that there are strong host-guest interactions between the framework oxygen atoms of zeolite and ZnO clusters influencing the motions of the framework oxygen atoms. The interaction may be the reason why ZnO clusters are stabilized in the pores of zeolites. Different from bulk ZnO materials, these sub-nanometric ZnO clusters exhibit their absorption onset below 265 nm and show a purple luminescence band (centered at 410-445 nm) that possesses high quantum efficiency and quantum size effect. This purple luminescence band most likely originates from the coordinatively unsaturated Zn sites in sub-nanometric ZnO clusters. On the other hand, the differences in the pore structure between HZSM-5 and HY zeolites cause the absorption edge and the purple luminescence band of ZnO clusters in ZnO/HZSM-5 show a red shift in comparison with those of ZnO clusters in ZnO/HY.
Resumo:
In this paper, we report for the first time on the synthesis of ZnO nanocrystallites in conjugated polymer (PPV) nanofibers by the coupling of the in situ/blend methods and electrospinning. These composite nanofibers were characterized by fluorescence microscopy, atomic force microscope (AFM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra, Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffraction (XRD).
Resumo:
This paper describes a new strategy to make a full solid-state, flexible, dye-sensitized solar cell (DSSC) based on novel ionic liquid gel, organic dye, ZnO nanoparticles and carbon nanotube (CNT) thin film stamped onto a polyethylene terephthalate (PET) substrate. The CNTs serve both as the charge collector and as scaffolds for the growth of ZnO nanoparticles, where the black dye molecules are anchored.
Resumo:
Novel 3D wurtzite ZnSe hierarchical nanostructures have been synthesized by a mild hydrothermal treatment. The as-prepared flowerlike nanostructures efficiently catalyze the photodegradation of methylene blue and ethyl violet present in aqueous solutions under UV light irradiation, exhibiting higher photocatalytic activity than the commercially available photocatalysts P25 and ZnSe microspheres. We also demonstrate that flowerlike morphology is important for the excellent photocatalytic activity.
Resumo:
Submicrometer zinc oxide (ZnO) with different morphologies including spindle-like, pencil-like, branch rod-like and frizzy flower-like shapes, have been hydrothermally synthesized in mixed solvents of ethanol and water at 140 degrees C. It was found that the volumes of added ammonia, surfactant (cetyltrimethylammonium bromide, CTAB), and mixed solvent play crucial roles in morphological control of ZnO nanostructures. Increasing the volume of ammonia added to the reaction system, the shape of ZnO evolves from spindle into branch rod-like. Synergetic influence between CTAB and ammonia can only be observed at high concentration of ammonia.