Study Of Photoanodes Of Quantum Dot Sensitizers Solar Cells

As one member of the third generation solar cell, quantum dots sensitized solar cell?QDSC? has the advantages of high theoretical conversion efficiency, low costing and simple processing. QDSC is becoming a hot topic in the field of solar cell in recent years. The QDSC is composed primarily of photoanode, electrolyte and photocathode in which many researchers have invested much time and energy. This paper focus on the studying of photoanode and electrolyte. By changing the components of electrolyte, the preparation procedure and the kind of sensitizer, the QDSC got a high conversion efficiency.In this paper, the CdS QDSC has been prepared by Succession ions layer absorption and reaction?SILAR? firstly. And then, the sulphur, sodium-sulfur, potassium chloride and sodium hydroxide were dissolved in methanol aqueous solution to prepare polysulfides electrolyte. By adjusting the components of electrolyte, we exploring how does the electrolytes affect the photovoltical performance of CdS QDSC. The result showed that the photovoltaical properties of QDSC were greatly increased under certain proportions of components in electrolyte.The cadmium sulfide-selenium photoanode was prepared by SILAR. The sodium sulfide-selenium anionic precursors was synthesized by employing selenium powder and sodium sulfide. The cationic precursor was prepared by mixing cadmium nitrate and manganese acetate. The composition of the sodium sulfide-selenium precursors and Mn²⁺ doped cadmium sulfide-selenium QDs were characterized with the Raman spectra and EDX. The change of light absorption capacity of photoelectrodes were analyzed by the UV-Vis absorption spectra. EIS and IPCE were used to characterize photovoltaic performance of the prepared QDs-sensitized photoanode. The results showed that the Mn²⁺ doped cadmium sulfide-selenium QDs evenly distributed on the surface of the TiO₂ film, and the power conversion efficiency of QDSCs with Mn²⁺ doped cadmium sulfide-selenium QDs increased 240% compared with that of QDSCs with CdS QDs. This is attributing to the improved optical and electronic properties of Mn²⁺ doped cadmium sulfide-selenium semiconductor caused by introducing Se and Mn²⁺.The sodium sulfide-telluride was synthesized by using S, Te and sodium sulfide. The cadmium sulfide-telluride was applied to fabricate quantum dots solar cell by SILAR method for different number of cycles in sodium sulfide-telluride and cadmium nitrate. The Raman spectra and electron diffraction spectrum were measured to investigate the elements and structure of sodium sulfide-telluride. The photovoltic property of cadmium sulfide-telluride was characterized by UV-Vis and J-V curve. These results shows that the long lifetime of charge carrier and high availability ratio of light of cadmium sulfide-telluride QDSC are found to be the major advantages over the cadmium sulfide QDSC. Those factors are leading to that the maximum conversion efficiency of cadmium sulfide-telluride QDSC is 26% more than that of cadmium sulfide QDSC.The CdS quantum dots?QDs? were prepared via reversed micelles and then the QDs were fabricated on the surface of TiO₂ film electrode to prepare CdS QDSC photoanode. The effect of QDs prepared process on the photovoltical performance by utilizing the Triton X-100 was studied and characterized. The results showed that the different formulation variables of the reversed micelles formulation can affect the photovoltaic properties of CdS QDSC. However, the QDSC could obtain the higher photovoltaic properties by SILAR than reversed micelles method.