| With the development of society, the demand for energy is increasing. However, the environmental pollution is being worse, and the price of petrochemical traditional energy is booming, people are forcing to seek new clean and renewable energy. As being the most convenient accessed clean energy, Solar energy is considered to be one of the best alternative sources of energy, high efficient exploitation and utilization of solar energy has become an important part of countries strategy of sustainable development. Using photovoltaic cells is the most direct way of using solar energy. Monocrystalline silicon solar cell has the very high energy conversion efficiency, but its high cost and the environmental problems limit its development in the process of production. Polycrystalline silicon solar cell with low cost has the low battery efficiency, while amorphous silicon solar battery constantly is balancing the cost and efficiency, the cost of solar cells will not be able to compete with traditional energy. Quantum dots sensitized solar cell (QDSSC) as a new type of solar cell, which has the advantage of simple process, low cost, the relevant theoretical research show that quantum dots have unique quantum size effect, quantum confined effect, impact ionization effect and Auger recombination effect and miniband effect, those characteristics make the quantum dots sensitized solar cell can obtain as much as 66% of the photoelectric conversion efficiency. Therefore, the research for quantum dots sensitized solar cell receives wide attention and research of global scientists, to realize the safe and reliable, no noise, no pollution, low cost, high energy conversion efficiency imagined solar cells.Firstly, this paper use nanometer ball on conductive glass to compound three-dimensional orderly titanium dioxide (TiO2), and adopt successive ionic adsorption and reaction (SILAR) method to compound quantum dots (QDs),such as CdS and CdSe, PbS. Secondly, those quantum dots will assemble one by one in the three-dimensional ordered TiO2 surface as the quantum dot sensitized solar cell sensitizer, to investigate the influence of the sensitized of quantum dots to battery photoelectric conversion efficiency, in order to improve the efficiency of the cells. This paper mainly has done the following works:1. To prepare three-dimensional orderly titanium dioxide and improve the production processIn the preparation of the three-dimensional ordered TiO2 and quantum dots synthesis, this study optimizes the synthesis process to explore the optimum conditions. By scanning electron microscope observes the three-dimensional ordered TiO2, which detect the hole with rules, and it has high surface area. That can promote the growth of quantum dots and electronic transmission or separation of the hole.In the synthesis of quantum dots by using SILAR method, this study compares the influence of the water and alcohol solution to synthetise quantum dots, we find that alcohol solution is more advantageous to the synthesis of quantum dots.2. To prepare quantum dots and analyze the optical propertiesIn this study, we synthetise the four quantum dots sensitized structure, such as CdS, CdS/CdSe, CdS/CdSe/PbS, PbS/CdS/CdSe. Through uv-vis spectrometer to obtain the quantum dot absorption spectrum, the results showed that the CdS and CdSe quantum dots of light absorption are highly, but CdS/CdSe/PbS were not showed the good sensitized complementary as much as CdS/CdSe.3. Cell optimize and surveying the efficiencyiesIn the TiO2/CdS/CdSe anode structure, due to the oxide semiconductor quantum dots and the conduction band and valence band between the ladder, it can contribute to the conduction of electrons and holes, the results showed that the TiO2/CdS/CdSe electrode structure of the cell with 2.09% efficiency.Adding PbS quantum dots to form TiO2/CdS/CdSe/PbS electrode structure, but PbS quantum dot shortens the life of electronic, the cell efficiency has not been significantly increased, even the electrode structure of TiO2/PbS/CdS/CdSe declines the efficiency compare to TiO2/CdS/CdSe electrode structure. Eventually TiO2/CdS/CdSe/PbS electrode structure of the cell has received 1.36% efficiency.At the same time, this study adopt the zinc sulfide (ZnS) and ammonium fluoride (NH4F) to promote the growth and stability of the quantum dots, the results show that the cell after adding ZnS and NH4F achieve the best battery 3.75% efficiency. That indicates the ZnS and NH4F can promote the growth of the quantum dots and improve the stability of quantum dots, ZnS can also pad the space which are not attach with quantum dots in TiO2 to prevent the occurrence of leakage current, improve the efficiency of the battery. |
