Quantum-Dots Sensitized Solar Cells Based On One-Dimentional Tio₂

Quantum dots(QDs) with special photoelectric properties show significant values in the feilds of bio-labeling, photoelectric devices and solar cells. Different grain size and composition of QDs can absorb photons with various energy and give off wide wavelength of luminescence. The therotical conversion efficiency of QDs sensitized solar cell (QDSSCs) predictes a high value of44%, while the experimental results shows a much lower outcome.This thesis reported the fabrication process of QDSSCs. One-dimentional TiO2structure was synthesis and CdS/CdSe QDs directly deposited on TiO2photo-anode by successive ion layer adsorption and reaction (SILAR). An entire solar cell was assembled after the optimization of electrolyte and counter electrode. The improvment of cells’structure and performance are carried out to enhance the conversion efficiency. Besides, the synthesis of pyrite FeS2, a nanocrystal whose absorption bands are in high coincidence with the solar spectrum, is conducted combining with solar cells characterization and performance test.The main research contents and results are listed as follows:(1) By hiring anodic oxidation treatment for Ti metal foils at certain voltage and ambient temperature,1D anatase TiO2nanotubes (TNTs) with different sizes were obtained. Then1D-TiO2nanowire was synthesis directly on transparent FTO glasses, which is a necessery precondition for the assemble of solar cells.(2) The deposition of CdS/CdSe QDs to1D-TiO2SILAR and assemble of sandwich type solar cells was investigated with desirable electrolyte and counter electrode. Based on an comarison of three types counter electrodes, CoS/CuS electrode shows better performance rather than Pt or CuS electrode, combining with merit of simple process and cost-performance compatibility. Oppose to rear-side irradiation direction, front-side way shows an improved performance with a current density of6.40mA/cm2.(3) Pyrite FeS2nanocrystal can be obtained by both solvothermal and hydrothermal method, with particles size of40-50nm and5-10nm, respectively. After deposited them onto1D-TiO2, an FeS2sensitized solar cells was achieved with a current desity of5.2mA/cm2and an open voltage of26mV.