Ⅱ-Ⅵ Inorganic Semiconductor Quantum Dots Sensitized Solar Cells

Inorganic Semiconductor Quantum Dots (QDs) and porous film are two important parts of quantum dots sensitized solar cell (QDSSCs). And they play decisive roles in the performance of solar cells. In order to improve the performance, three aspects that are the property of porous film, the new method of preparing QDs and the assembly way of QDs in the porous film are studies in this paper.TiO2-SiO2composite films are prepared through a simple process, and applied in quantum dot sensitized solar cell in this paper. The surface area, pore volume, and aperture of TiO2film are controlled effectively duo to the incorporation of SiO2. Such the adsorption capacity of quantum dots is increased. SiO2forms barrier, which inhibits interface charge recombination. Then photocurrent is increased. Solar cells are assembled by the anode which is prepared using colloidal CdSe QDs sensitized TiO2-nano-SiO2composite films. CdSe QDs can be adsorbed onto the TiO2-SiO2film better through the exchange of ligand. Then the photogenerated electrons transfer can be promoted, the charge recombination can be reduced, and the efficiency of solar cell can be improved. The result shows that Solar cell which is assembled by the CdSe QDs sensitized TiO2-nano-SiO2photoanode has an efficiency of1.74%.A new gas-thermal liquid (hot-bubbling) method is explored to prepare CdSe QDs in the paper. Its effect on the photovoltaic properties of QDSSCs was investigated. The performance of CdSe QDs is studied by the reaction time, the Cd:Se concentration, and the reaction temperature. The result shows this method can synthesize zinc blende CdSe QDs with the uniform size and good dispersion under the proper reaction conditions.QDSSCs are assembled through the anodes which are sensitized by CdSe quantum dots prepared by the hot-bubbling method. The photovoltaic performance of QDSSCs is investigated. The experiment shows that the solar cell which is sensitized by CdSe quantum dots has an efficiency of1.94%. It can be used as a new preparation method to extend.The successive ionic layer adsorption and reaction (SILAR) and the self-assembled monolayer (SAM) methods are combined to obtain the CdS/CdSe co-sensitization TiO2-nano-SiO2composite films. Namely, CdS and CdSe QDs are assembled onto TiO2-nano-SiO2film by the SILAR and SAM respectively. Meanwhile, the assembling routes are green duo to using aqueous solvent in the whole process. The new assembly mode can achieve a high coverage of the TiO2-nano-SiO2surface, get a good control of the size distribution, and lower the defect state that has produced by the multilayer deposition. At the same time, the charge recombination between the photoelectron and electrolyte can be inhibited effectively. The effect on the properties of solar cells is discussed through CdS deposition process. The CdS optimal deposition cycles are determined. The effect is studied on a micro level. The assembly method offers a certain reference meaning to other types of quantum dots in the co-sensitized solar cells.