Polymer-assisted Deposition Route For Designing The Buffer Layer Of Solar Cells

Recent years, utilize the solar energy is one of the most important ways to solveenergy crises. Solar cell becomes a useful technology to realize the goal. However, thefabrication of the current solar cells include either the complex technology or expensiveequipment. All these limit the wide applications of solar cells. In order to reduce the cost,one kind of chemical solution approach, the polymer-assisted deposition, is tentative toapply in the fabrication of solar cells. The thin films are grown and applied in the differentkinds of solar cells. The main subjects of this work are concluded as follows:1. In general, TiO2in the dye-sensitized solar cell is synthesized by TiCl4as theoriginal material. However, due to the unstability of the TiCl4aqueous solution, it is easyto be hydrolyzed to TiO2or Ti (OH)4with muddy and precipitate. Therefore, it is achallenge to maintain the solution for a long time. In this thesis, we develop an approach toenhance the stability of Ti4+ions by combining the metal ions with the polyethyleneimine(PEI). Herein, the metal polymer interaction is the formation of covalent complexes orstatic electricity between the lone pairs on the nitrogen atoms and the metal ions. Theuniform solution is spin-coated on substrate, then annealed in air, forming the TiO2film.The film is uniform, dense, without any visible cracks. The TiO2film applied indye-sensitized solar cell as the compact lay with better performance than that with TiCl4aqueous solution deposited compact layer.2. The molybdenum oxide film can block the recombination of electron and hole pairas hole transport layer in organic solar cells. Herein, the molybdenum oxide is grown onLaAlO3substrate by polymer-assisted deposition. The XRD pattern and HRTEM indicatesthat the molybdenum oxide is epitaxial grown on LaAlO3. We also attempt to use this method to fabricate the molybdenum oxide film in the organic solar cells. These resultsdemonstrate that the PAD method provides an alternative strategy not only for the epitaxialfilm growth but also for the solution processing for the low-cost fabrication of futurematerials’applicationin the field of renewable energy.3. To find new composites’ materials, the development of fabrication routes/methodsis necessary. We introduce a polymer-assisted chemical solution route to synthesize theelectrode composite materials, carbon nanotube hybrid fbers. The Ti precursor ispermeated to carbon nanotube fiber, upon annealing in the controllable atmosphere, ahomogeneous TiC network is formed in the CNT fbers. The obtained CNT/TiC hybridfbers show prominent enhancement in mechanical strength and electrical conductivity. Thetensile strength and conductivity of CNT/TiC fbers can be improved to0.67GPa and1650S cm-1at room temperature. As-obtained CNT/TiC fbers is promising to be analternative electrode material in some special fields (such as high strength demand udnerthe harsh environment).