Self-Assembly And Photoelectric Properties Of PPV/C₆₀(OH)_n Multilayer Films

With the development of the research on organic photon material, many photon phenomena in conventional material had been detected such as photoelectric transform, electroluminescence.The photon material included conjugated polymers, fullerene material and organnic little molecule containing good it conjugated system. Polyparaphenylenevinylene(PPV) has been paid attention to because of good photoelectric property and peculiar molecule framework ; fullenene have three-dimensional conjugated structure and diminutive electron binding energy, and its peculiar structure and property has interested photoelectric scientist. As an electronic acceptor,C60 can enhance the efficiency of organic photoelectric cells compounded with PPV.But The little solubility of C60 in common organic solvent limited its application, and processing measure need more researchment. The ionic self-assembly deposition technique is a newly developed technique used to fabricate thin films of photoelectric parts with its main advantages: easy operation, controllable film thickness and compound in molecular size.In the paper PPV polymers precursor which can be used in ionic self-assembly has been synthesized .The structure of PPV is described with IR spectrum and UV-Vis spectrum; the best temperature of heat treatment is 250 C by DSC; energy level of PPV is obtained by PL spectrum,and its emisive light is yellow-green fluorescence. Aqueous soluble fullerene derivative(fullerenol) is synthesized by the reaction of C60 with NaOH and fuming sulfuric acid respectively. The structure of fullerenol is described with IR spectrum and UV-Vis spectrum; The researching of UV-Vis spectrum show that the latter can be well used to ionic self-assembly.Ionic self-assembled multilayer films were prepared by the reaction of PPV precursor with C6o(OH)n on the glass. The film were examined by UV-Vis, PL, Raman, XPS and step apparatus. The photoelectric cells of PPV/C6o(OH)n multilayer films were prepared with ITO glass and Al film as electrod. photoconducti and photovoltage of photoelectric cells is measured by CHI-660 electrochemistry workstation in light of 100W tungsten lamp, andelectroluminescence of the multilayer films is also measured by F4500 fluorescence spectrophotometer.The result show that PPV and C6o(OH)n in the ionic self-assembled multilayer films have nothing to do with each other on the ground state, but light arise charge transfer between PPV and C6o(OH)n on the excitation state, and the structure of electron donor-accepter is formed in the films. In the light of 100W tungsten lamp, the conductance of the films increased 102~104 times, and the largest photovoltage is 0.152V/cm2.