SnO2 nanoparticles were found to self-pack at the air-hydrosol interface and form a nanoparticulate film. The self-packed films were observed under a Brewster angle microscope, and investigated by recording the time evolution of surface pressure and π-A isotherms. The results show that SnO2 nanoparticles take 3h to form a complete film at the air-hydrosol interface. Composite monolayers of SnO2 and arachidic acid were obtained by spreading arachidic acid onto a fresh hydrosol surface. Composite Y-type LB films were transferred from the air-hydrosol interface onto substrates, and characterized by FTIR, UV-vis, X-ray diffraction spectroscopy and TEM techniques. The results show that the composite films have good structure, with SnO2 nanoparticles uniformly and compactly distributed in the arachidate matrix.

The ferric oxide nanoparticles-tris-(2, 4-di-t-amylphenoxy)-(8-quinolinolyl) copper phthalocyanine (CuPcA2) composite ultrathin film was obtained by LB (Langmuir-Blodgett) technique. Structure of the composite LB film was characterized by X-ray photoelectron spectra, transmission electron microscopy, infrared spectra and visible spectra. Gas sensitivity measurements indicate that the composite LB film is sensitive to 100-200 ppm C2H5OH at room temperature.

Stable monolayer of the polyaniline doped with camphor sulfonic acid at the air-water interface has been obtained, of which multilayers have been successfully deposited by Langmuir-Blodgett technique onto CaF2 substrate. The limiting mean molecular area and collapse pressure are found to be 0.294nm 2 and 41mN/m, respectively. The multilayers were characterized by IR and UV-Vis-NIR spectroscopies. X-ray small-angle diffraction data show that the multilayer was periodic layer structure with the layer spacing of 1.60nm. The comparisons are also made with characterization of the casting film.

Surfactant-stabilized SnO2 nanoparticulate organosol was prepared. The organosol mixed with arachidic acid was spread on water surfaces in a Langmuir-Blodgett (LB) balance. Surface pressure versus surface area isotherms were determined. The surfactant-stabilized SnO2 nanoparticulate monolayers were transferred, layer-by-layer by the LB technique, to solid substrates. Then the multilayers were characterized by Fourier transform IR spectroscopy, UV-visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The results indicate that the multilayer is composed of SnO2 nanoparticles and arachidic acid. It forms a Z-type periodic structure with a long spacing of 7.48nm, i. e. a kind of three-dimensional superlattice.

ZnS/CdS/ZnS quantum dot quantum well was prepared. The optical properties of ZnS/CdS/ZnS QDQW with different thickness of CdS well and ZnS shell were studied. Absorption spectra, emission spectra, and luminescence lifetimes were measured. The observed luminescence was assigned to the bulk donor-acceptor pair recombination of CdS and can be enhanced by increasing the thickness of the CdS well or coating an appropriate thickness of ZnS shell on the surface of the CdS well. The luminescence enhancement was caused by the relative reduce in the surface effect. The luminescence lifetimes were influenced strongly by the surface state.

A ZnS/CdS/ZnS quantum dot quantum well was prepared in AOT micelles successfully and was characterized by absorption spectroscopy and fluorescence spectroscopy. Luminescence in the region of 350-600nm was observed. The complete ZnS shell might reduce the number of defects on the surface of the CdS well, which were assumed to act as centers for radiationless recombination, resulting in the luminescence enhancement.

Mn2+-doped ZnS nanoparticles and Mn2+-doped ZnS nanoparticles coated with a shell of ZnS were prepared in reverse micelles. Mn2+ emission at 580 nm in the coated nanoparticles was seven times stronger than that in the uncoated ones. Ultraviolet light treatment enhanced the luminescence at 580 nm in the uncoated nanoparticles, but led to no luminescence enhancement in the coated ones. Some calculations indicated that Mn2+ ions were not randomly distributed in the particle, but preferred to occupy the sites close to the surface. The experiment results indicated that ZnS shell and UV treatment could block the nonradiative transition paths and led to the enhancement of luminescence.

A novel method using LB films as precursors to prepare pure inorganic ordered film with periodic structure was developed. Surfactant-stabilized SnO2 nanoparticulate organosols and TiO2 nanoparticulate organosols were prepared and used as spreading solutions. Using LB technique, the good film-forming ability of the surfactant-stabilized SnO2 nanoparticles and TiO2 nanoparticles was confirmed by the determination of the π-A isotherms. The surfactant-stabilized SnO2 and TiO2 nanoparticulate monolayers were fabricated on the water surface and then were transferred to solid substrates (CaF2, quartz, silicon, and so on) alternately, layer-by-layer. Then the as-deposited alternate LB film was treated at different temperatures. The as-deposited alternate LB film and the treated film were characterized by Fourier transform infrared spectroscopy, UV-visible spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that our method was successful. The as-deposited alternate LB film formed a periodic structure with a long spacing of 6.5nm that was composed of SnO2 nanoparticles, TiO2 nanoparticles, and arachidic acid. The treated film composed of SnO2 nanoparticles and TiO2 nanoparticles formed a pure inorganic periodic structure with an ordered distance of 5.4nm.