| Because of the friendly with environment, clean, inexhaustible, solar energy become preferred energy to solve the energy crisis and environmental problems at present. Solar cells as a photovoltaic devices become an important task. So far, solar cell go through different stages. Eventually people locked in dye sensitized solar cells because of its low cost, simple in production. While traditional dye is pollution with the environment, it has never stopped to explore new sensitization agent in recent years. The quantum dots have good optical and electronic properties, it has been widely used in semiconductor devices, memory and biomedical tags. So quantum dot as a new sensitization agent to solar cell as a new type of dye sensitized solar cell called quantum dot sensitized solar cells which is in the high speed development stage.In the past, scholars usually put study center on the particle size of the quantum dots. It is not easy to control the particle size due to the influence from variety factors. It achieve the purpose of adjusting the energy level structure by controlling the content of elements in the quantum dots. In this paper, it prepared CdSeS quantum dot by hot injection method. Then the quantum dots with different energy levels are successfully obtained. The influence factors on the performance of ptype quantum dot sensitized solar cells are studied from two aspects of quantum dot and NiO thin film. Through that improve the performance of p-type quantum dot sensitized solar cell. The detailed content as follows:The first chapter is the introduction, which mainly introduces the research background of this topic. Firstly, it is the summary with development of solar cells. Secondly, it was studied the structure, working principle and research progress of the quantum dot sensitized p-type solar cell. Finally, it was explained the problems at the present and the solutions of quantum dot sensitized p-type solar cells in this experiment.In the second chapter, it was illustrated the preparation and characterization of CdSeS quantum dot. In the experiment, the CdSeS quantum dots with different ratio of S and Se elements were synthesized by the method of heat injection on the basis of the synthesis of CdSe and CdS quantum dots successfully. The test results of TEM, AFM and XPS make us known the performance of this new quantum dot. From the absorption spectra, it can be seen that the absorption bands of CdSeS quantum dots regular shift with different ratio of Se and S. So the energy level structure of the quantum dots can regulate and control by changing the element content instead of conventional control of the quantum dot size.In the third chapter, we study the performance of nickel oxide films sensitized with a series of quantum dots with different radio of selenium and sulfur. The working process of CdSeS quantum dot sensitized nickel oxide thin films was studied deeply. This scheme can further improve the conversion efficiency of quantum dot sensitized solar cells by tuning the ratio of the quantum dots. The final optimized in quantum dot sensitized solar cell sensitizer of CdSeS quantum dot the best Se:S ratio was 1:5. At this time, the photoelectric conversion efficiency(1.02%), short circuit current(14.68 mA cm-2) and the open circuit voltage(232mV) were better compared to other radios. It was studied deeply of the CdSeS quantum dots(Se:S=1:5) sensitized oxidation of nickel film performance. The reasons:(1) the charge separation efficiency is the highest, battery internal resistance is the minimum;(2) long transmission life is conductive to improve the hole collection efficiency, thereby to enhance the photoelectric current density.In the fourth chapter, we study the effect of polyethylene glycol on the performance of the quantum dot sensitized p- solar cell. The working electrode of nickel oxide cathode electrodes were prepared by scraping coating method. Because of the thin film thickness is small and does not firm affect the photoelectric performance of the battery. In this study, polyethylene glycol was used to optimize the performance of the film. Through the research of the amount of polyethylene glycol in the thickness of the nickel oxide film, the best ratio of polyethylene glycol and the best thickness of the coating film were optimized. At this point, the photoelectric conversion efficiency of the quantum dot sensitized solar cell was 1.28%, the open circuit voltage 240 mV, the short circuit current 17.06 mA cm-2 and the filling factor was 30.5.The fifth chapter were summarizes and prospects of the work. |
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