The Research Of Quantum Dots Sensitized Solar Cells Based On TiO₂ Nanotube Arrays

In this paper, the quantum dots-sensitized solar cells (QDSSCs) based on photoanodes which were composed of TiO2 substrate and quantum dots (QDs) were constructed. The photovoltaic performances of QDSSCs were systmtatically discussed. The main works completed in this paper are listed as following:(1) The experimental conditions for fabrication of TiO2 nanotubes were probed. The influence of NH4F concentration in electrolyte and the influence of anodized voltage on the morphology of TiO2 nanotube were investigated.(2) CdSe/CdS QDs sensitized TiO2 nanotube solar cells were fabricated by two-second anodization process and successive ionic layer adsorption and reaction (SILAR) approach. The fabrication process and the photoelectrochemical properties of the photoanodes were systematically discussed. The results showed that the CdSe/CdS QDs, the ZnS passivation layer, and photoanode illuminated way are in favor of enhancing the photovoltaic performance of QDSSCs.(3) The ZnxCd1-xSe QDs sensitized TiO2 nanotube (NT) array solar cells were fabricated. The photovoltaic performances of ZnxCd1-xSe QDs sensitized TiO2 nanotube solar cells were investigated, and the results showed that the increase of Cd in ZnxCd1-xSe alloyed QDs can enhance the power conversion efficiency of QDSSCs.(4) Different nanostructured TiO2 films which and were used as substrate materials in QDSSCs were prepared by varying the voltage during the second anodization process. The CdSxSe1-x alloyed QDs were incorporated onto the nanostructured TiO2 films including TiO2 NT (nanotube), TiO2 NW (nanowire), and TiO2 NW/NT (nanowire/nanotube) by one step hydrothermal process. Systematic investigations were conducted to find out the relationship between the photovoltaic performance of solar cells and the variation of S and Se in CdSxSe1-x alloyed QDs. The influence of TiO2 nanostructures on photovoltaic performance of QDSSCs was also investigated.(5) The translucent TiO2 NW/NT film was prepared by two-step anodization process, and was sensitized with CdSe/CdS QDs by SILAR method for QDSSCs. The photovoltaic performances of the CdSe/CdS QDs-sensitized TiO2 NW/NT solar cells were investigated.(6) The CdSxSe1-x/Mn-CdS/TiO2 NT QDSSCs were prepared by combining the SILAR and hydrothermal methods. The J-V behaviors of the CdSxSe1-x/Mn-CdS/TiO2 NT QDSSCs were systematically studied. Further deposition of CdSe QDs to form CdSe(3)/CdSxSe1-x/Mn-CdS/Ti02 NT solar cell can improved the power conversion efficiency to 3.26%.