Application Of TiO₂Nanotube Arrays Modified With Rare-earth/Graphene Oxide In Dye-sensitized Solar Cells

With the rising costs of fossil fuel including coal and petroleum, people havebegun searching for new ways of generating and producing energy because the hugeenvironmental problems caused by greenhouse effect. Solar power is the conversionof sunlight into electricity. A high efficient, low-cost and easy preparation ofDye-sensitized solar cells was developed by Gr tzel in1991. As the Photoanode ofDSSC, ordered TiO2nanotube can improve the ability of directional transmission ofelectrons as well as enhance the utilization ratio of light electrons and holes, it is alsofurther promote the photoelectric conversion efficiency of solar cell. However, thearray can’t limit the compound of electron-hole due to broad band TiO2, and theabsorption of visible light would be reduced.Rare-earth ions exhibit excellent conversion light. The utilization ratio of lightand specific surface area is increased by introduction of rare earth ions into TiO2nanotube. Graphene oxide (GO) has a unique physicochemical properties, theperformance of its composites with other inorganic semiconductor materials will befurther improved. The thesis mainly focused on the investigation of the effect of theas-prepared Rare-earth solution and graphene oxide solution on photoelectricconversion efficiency. The detailed researches and results are listed as follow:（1）The TiO2nanotube was modified by hydrothermal method using AqueousEu(NO3)3and then assemble to the DSSC. The results shows that the Eu2O3nanoparticles are formed on the surface of TiO2nanotubes, it increase the amounts ofdye loading, the optimal short circuit-current density and conversion efficiency is11.7mA cm-2and6.58%, increasing by36%and37.6%compared with the DSSCbased on the pure TiO2nanotube under a simulated solar light irradiation of100mW cm-2. （2）The TiO2nanotube was modified by hydrothermal method using AqueousEr(NO3)3and then assemble to the DSSC. The results shows that the Er2O3nanoparticles are formed on the surface of TiO2nanotubes, it increase the amounts ofdye loading, the optimal short circuit-current density and conversion efficiency is12.5mA cm-2and6.77%, increasing by45%and41.6%compared with the DSSCbased on the pure TiO2nanotube.（3）Aqueous graphene oxide was prepared from purified graphite powders by amodified Hummers’ method，The TiO2nanotube was in an immersion processing. Atthe proces, the GO/TiO2composite was achieved. The results shows that thecomposite GO/TiO2nanotube arrays has an enhanced absorbance throughout thevisible light region. the short circuit-current density and conversion efficiency is13.2mA cm-2and6.22%, increasing by53%and30%compared with the DSSC basedon the pure TiO2nanotube.