| The 'photon era' of the 21st century is coming, and already!In the last decade, nanometer science, material science, microelectronics and supramolecular science have been rapidly developed, so they can provide essential prerequisite for the study of novel inorganic-organic photoluminicent and photochromic materials. It is a fact that functional film materials play a great role in material science. Organized molecular film, fabricated mainly by Langmuir-Blodgett method, self-assembling technique and polyelectolytes alternating deposition technique, have various potential applications hi the fields of nano-materials, sensors, optical devices, ect.Polyoxometalates (POMs), a class of molecularly defined inorganic metal-oxide clusters, posses intriguing structures and diverse properties and, therefore, attract increasing attention worldwide. For this, it will be of critical importance to successfully incorporate the functional properties of POMs into the ultrathin material. In this thesis, author carried out a series of research hi photoluminicent and photochromic film based on POMs, and some constructive and helpful results were obtained. All the results are summarized as follows:1. A series of photoluminecent multilayer films, (PEI/PSS/PAH/ (POM/PAH)n} (POM = [Eu(BWn039)2]15~ , [Eu(SiWn 039)2]13" . [EuPsWaoOno]12") ?were successfully fabricated by electrostatic layer-by-layer assembly. UV-vis spectroscopy was used to follow the absorbance with increasing the number of bilayer indicates a process of uniform assembling. The XPS measurements not only confirmed the presentation of POMs and PAH in multilayer films, but also showed that the peak intensities of the W4f and Njs levels increase as the number of (POM/PAH) bilayers increases, in agreement with result from the UV-vis spectra. The AFM images of the POM/PAH film show that the surface ofthe film is homogeneous and the coverage is high. The roughness of the surface of the film was calculated to be less 0.8 nm. It is regret that the satisfactory Kiessig fringes appearing in the X-ray diffraction pattern of a multilayer film was not obtained, and the thickness and roughness of film was not calculated accurately, either. The photoluminescent behavior of the multilayer film at room temperature was investigated to show the characteristic Eu3+emission pattern of 5Do~*7Fj. The fluorescence behavior of the multilayer is essentially identical to that of solid samples.2. A novel hybrid photochromic composite film composed of Preysslers heteropolyacid EuPsWso and PVP was prepared by dip-coating method. SEM was used to investigate the surface topography. The change of characteristic peak in the infrared spectra (IR) was investigated and it showed that the Preyssler geometry of EuPsWso was still preserved inside the hybrid film. The TG curve showed three steps of weight loss and approximately revealed the composition of the hybrid film, (VP)42(EuP5W3o)(H2O)io2. XPS, UV-vis and ESR were used to investigate the photochromic behavior and mechanism of hybrid film. From the above result, one can draw a conclusion that charge transfer took place between the organic and inorganic species under UV irradiation. Furthermore, the photoluminescent behavior of the multilayer film at room temperature was investigated to show the characteristic EuJ+emission pattern of 5Do-7Fj. |
PDF Full Text Request