Study On The Application Of ALD Deposited Al₂O₃in Dye Sensitized Solar Cell

In1991, Gr tzel et al invented dye sensitized solar cells （DSSCs） withnanotechnology, and the conversion efficiency is increased to7%, which opened theera to the development of dye sensitized solar cells. Due to a low cost process, such asno high energy consumption, without vacuum，raw materials available easily, simplemanufacture process, DSSCs demonstarte a remarkably advantage than traditionalsilicon solar cells. Therefore, in the past twenty years, the dye sensitized solar cell hasbeen widely studied in the world. And it was considered to be the one of candidates toachieve the large-scale application in solar cell.But there are many challenges for dye-sensitized solar cells, such as the electronmobility rate of titanium dioxide is lower, the leakage of liquid electrolyte and thepoor stability. Therefore, in this paper we prepared the cell with tin oxide as anodematerials for liquid dye-sensitized solar cell and the PEO based polymer compositesolid electrolyte for solid-state dye-sensitized solar cell. And then an ultra thin Al₂O₃layer coated on anode for improvement the efficiency of dye-sensitized solar cells iscarried out in this thesis.We explore the role of an ultra thin Al2O3layer coating SnO2particles fordye-sensitised cells energy conversion efficiency, which was used in TiO2photoelectrode due to Al₂O₃building a potential barrier layer in the photoelectrode/dyes/electrolyte interface to suppress the interfacial charge recombination. Besides,due to a higher isoelectric point,Al2O3coating promotes the dye absorption andimproves cell efficiency. Based on the dye absorption amount depending on the ALDprocess parameters we construct a three-step model of the ALD Al2O3in porous SnO2photoanode toexplain the effect of Al₂O₃coatings.We also use ALD technology to modify the photoelectrode in the solid-state solarcell. After combined TiCl₄hydrolysis to prepare of Titania oxide with ALD aluminaoxide for two-layer structure, the charge recombination during electronic transmissionis suppressed and the connection between particles is significantly enhanced. The conversion efficiency of solid-state dye sensitized solar cells is promoted remarkably.