| Along with the worldwide increase of energy needs, traditional energy such as oil, coal and natural gas no longer meet the need for human development and how to make use of reproducible energy becomes a problem pressing for solution. Among all kinds of reproducible energy, solar energy is inexhaustible and so it is of great significance to research and develop high efficiency and large area solar cells. At present almost all of the commercialized solar cells are based on silicon or inorganic compounds semiconductor. But their application is restricted because of shortages such as high cost, high toxicity, hard for flexible manufacture and limited in resources. Conductive polymers have the electro optical characteristic of inorganic semiconductor and electroconductibility of metal at the same time, and they’re easy to manufacture, can be manufactured in large area with low cost. Thus polymer solar cell has been worldwide research hotspots and functional polymer/semiconductor nano-composite solar cell is one of the most important developing directions. Due to the low migration rate and visible light absorbance, unfavorable interface properties of donor and acceptor materials, the efficiency of polymer solar cells still cannot compare with traditional cells. As a result, increase the conductivity of polymer materials, improve the film forming technology and optimize the manufacture process further is a problem requiring urgent attention.The photocatalytic polymerization is a new method to prepare inorganic/polymer nanocomposites. It is initiated by semiconductor under UV illumination and synthesize composite in situ. The interface property is optimized because of the strong interaction between nanoparticles and matrix. Thus it overcome the shortcoming of unfavorable interface nature in common composite, apparatus made by such composite can gain high performance due to the effective separation of photoelectrons and holes.Conductive polypyrrole is one of the conjugated polymers which has good thermal stability and high hole mobility. And titanium dioxide is chemical stable as well as excellent photocatalysis and electron transfer properties.In this study we used a new improved sol-gel process to prepare carbon nanotube loaded titanium dioxide gel and polypyrrole/TiO2/CNT nanocomposite was prepared via the photo-polymerization induced by the CNT loaded TiO2 and polymer solar cells were assembled. The main results were outlined as follows:1. TiO2 particles loaded on CNT were prepared through a new improved sol-gel process at low tempreture(100℃). The XRD results indicated that the TiO2 particles were anatase crystallites. The Raman spectra change of frequency and peak relative height proved the strong interaction between CNT and TiO2.2. CNT-TiO2-PPy nanocomposites were prepared via photocatalytic polymerization of pyrrole monomer, TiO2-CNT as the initiator under the UV irradiation. UV-vis spectra showed that the composites’s absorbance of visible light was improved with the introduction of CNT.3. Through the steady-state and transient fluorescence analysis, a charge transfer process at the interface between CNT and TiO2 and also between TiO2 and PPy was found. And the charge process was further improved by the results of XPS and ESR.4. The CNT-TiO2 gel was formed into a thin film by a spin-coating method and CNT-TiO2-PPy composite film was prepared through photocatalytic polymerization. Then it was assembled into film electrodes. Photoelectric performance testing indicates that the introduction of CNT can improve the photoelectric performance of composite film largely. With the introduction of CNT, electron transfer channel was formed, photoelectrons could conduct rapidly so that the recombination of photoelectrons and holes is reduced, which was favorable for the generation of photocurrent. |
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