Nanostructured TiO2/Conjugated Polymer and Fe3O4/PAA Composites: Synthesis, Properties and Photovoltaic Application.
Date Issued
2007
Date
2007
Author(s)
Lin, Yi-Jun
DOI
en-US
Abstract
This thesis divided into three parts. The synthesis of metal oxide materials, including titanium dioxide (TiO2) and iron oxides (Fe3O4) were described in Chapter 1. The experimental procedures and characterization results of successful synthesis of crystalline TiO2, and Fe3O4 with various shapes and morphologies were reported and discussed in this chapter. In the following part of this work, the synthesis and characterization of TiO2 nanocrystals with a rather small particle size distribution were presented. The effects of titanium precursor concentration, solvent, and water content on the morphology and particle size distribution of TiO2 colloids were also briefly discussed. The diameter of these titania spheres can be easily tuned from 50 to 252 nm by varying the precursor concentration from 0.68 mM to 1.94E-2 M. Titania thin film produced by evaporation-induced self-assembly (EISA) route were also studied, which has a highly ordered mesostructure, narrow pore-size distribution, relatively high specific surface area, and very good thermal stability. Moreover, the structure was stable up to 400℃ and contains channel walls with anatase nanocrystallites. Importantly, under modified film aging conditions, optically transparent and crack-free thin films were obtained by the deposition onto a compact TiO2 layer. A part of this chapter presented the methods used to synthesize and characterize the magnetite materials. In the chapter, a series of magnetic materials with different shapes and morphologies were proposed and studied.
In organic/inorganic hybrid photovoltaic cells, the inherent incompatibility of inorganic particle and conjugated polymer frequently causes microscopic separation in the interface of two materials, thus significantly reducing its interfacial photo-induced charge transfer efficiency. In Chapter 2, a series of photoactive hybrids were prepared by the electrochemical polymerization of bithiophene into a nanoporous TiO2-coated ITO glass using chronopotential method in pure acetonitrile solution, or in a water/acetonitrile mixed solvent at different current densities. The growth conditions for the preparation of well defined smooth and adhesive polybithiophene films were demonstrated. Furthermore, the morphologies and electrochemical properties of the as-prepared polybithiophene/TiO2 photoactive hybrid materials were described in this chapter.
In Chapter 3, it describes the details of the preparation of organic solar cells by in-situ electropolymerization method. In photovoltaic cells, the use of an additional blocking TiO2 layer was essential to avoid short circuiting and loss of current through recombination at the FTO electrode. A method of preparation of a compact TiO2 layer by spray pyrolysis technique, and its standardization for the solar cell fabrication was discussed. The nature, structure and morphology of this layer with increasing thickness was examined with scanning electron microscopy (SEM), and the effects of this compact layer on the photovoltaic properties of the corresponding solar cells were also studied by looking into the current(I)-voltage(V) characteristics of a solar cell. Influences of the spraying cycles of this compact layer were also investigated in this chapter. The results indicated that an optimum spraying cycles of compact TiO2 layer was found to be the key issue to give the best results in terms of photovoltaic properties, and the layers of blocking TiO2 film should lie in the optimized region. In our experimental, this corresponds to below 10 spraying cycles in terms of surface morphology and photovoltaic properties. The results of this thesis demonstrate that this study provides a facile and successful route for growing conducting polymer from the porous TiO2 film. The cell power conversion efficiency could be further improved by optimizing the in-situ polymerization conditions, polymer structures, film morphologies, and contacts of metal/polymer/inorganic interfaces.
Subjects
電化學聚合
氧化鐵/聚丙烯酸複合材料
有機太陽能電池
TiO2/Conjugated polymer composites
electrochemical polymerization
Fe3O4/PAA composites
photovoltaic application
SDGs
Type
thesis
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