Study Of PPV Derivatives/ZnO Composite System And The Photoelectric Properties

The organic polymer solar cells have attracted much interest all over the world, but due to the poor charge carrier of polymeric material, short time of excited state which is formed after the polymers absorption of photon, and the low separation efficiency, therefore the photoelectric conversion efficiency of polymer solar cells is not high. The solar cells based on polymer/inorganic composite system not only have inorganic advantages of high carrier mobility, good chemical stability, but also retain the characteristics of polymer, which is low cost, design and work ability. It has attracted more and more attention. The photoelectric device based on the different active layer of conjugated polymer and inorganic nanocrystalline materials composite system were created in this dissertation, and make much research on the impact of the active layer to the device photovoltaic characteristics.After introduction of the research situation and development trend of organic polymer, polyphenylene vinylene (PPV) derivatives was studied. Four kinds of PPV derivatives with symmetrical and asymmetrical alkoxyl substitutes are prepared. They are Poly(2-methoxy-5-butyloxy-1,4-phenylenevinylene),Poly(2-methoxy-5-octyloxy-1,4-phenylenevinylene), Poly(2-methoxy-5-(iso-octyloxy)-1,4-phenylenevinylene),Poly(2-methoxy-5-dodecyloxy-1,4-phenyl enevinylene).The influences of synthesis route and reaction conditions are investigated roughly. The PPV derivations prepared through this way have good thermal stability and film forming ability, and have solubility in ordinary solvent. The solubility of PPV derivatives increased with the growth of substituted length. The peak value of UV-visible absorption and potoluminescence exhibits red-shift with the increased substituted length.Secondly, ZnO nanowires(ZnONWs)have been synthesized on Cu substrates through a modified vapor phase transport deposition process using a quartz reactor with a sealed end. The structure and size of the ZnONWs were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The reaction temperature and raw materials ratio were studied. These nanowires have an average diameter of-450nm and formed intertwined.Then on the basis of PPV derivatives and ZnONWs two structures of photoelectric device were prepared. One structure is based on heterojunction of ZnO which is separated from the substrates mixtec. witr. is(-PMOCOP(?). The results showed that the join of ZnO can significantly improve the photoelectric conversion efficiency of the devices. The other structure is ITO/PSS:PEDOT/(iso-PMOCOPV-ZnONWs)/Cu. The ZnO nanowires. which formed on the Cu substrates, were used directly as negative electrode materials for the photoelectric devices. To fabricate the active layer, the dissolved iso-PMOCOPV was spin-coated on the nanowires directly. It is found that the photovoltaic properties are improved significantly as compared to that of the first structure device. Finally, different devices were prepared by four different PPV derivatives which were spin-coated on ZnONWs directly. The coating morphology were characterized using SEM, the photovoltaic properties were studied. It is observed that the power conversion efficiency was1.37%of the device based on (PMODOPV+ZnONWs) is higher than the other polymers.