Fabrication Of Al³⁺ Doped Nano ZnO Structure And Its Effect On Properties Of Dye-sensitized Soalr Cells

Dye sensitized solar cell is a new type of solar cell. It has the advantages of simple preparation process, stable performance and low cost, so it has a good application prospect in the market. As one of the most important part in DSSC,nanocrystalline semiconductor photoanode plays an important role in the dye adsorption and electronic transmission. It has an important influence on the photoelectric properties of DSSCs.In this paper, ZnO photoelectric DSSC are studied.The contents of the study include:(1)We prepared ZnO nanorods on the FTO by chemical bath deposition method and applied it in DSSC. At the same time, we research the effect of its growth conditions and modified the seed layer by Al3+doping.(2)A special composite structure kind of ZnO nanorods with ZnO nanoparticles were fabricated by impregmating seed layer and used as photoanode in DSSCs.(3)The Al3+ doped ZnO nanoparticles were prepared by precipitation method,the Al3+ doped ZnO nanosheets were prepared by ultrasonic assisted precipitation method, the Al3+ doped ZnO nanospheres were prepared by alcohol heating reflux method. The morphology of ZnO seed layer,ZnO nanorods and ZnO powers were characterized by SEM. And DSSCs assembled by different photoanode films were tested through Ⅰ-Ⅴ curves and EIS impedance spectroscopy.The main research contents and results are as following:(1)ZnO seed layer was prepared on FTO via dip coating with two hydrated zinc acetate as zinc source, the mixture solution of ethylene glycol monomethyl ether and ethanol as solvent. Then nanorods were grown in the growth solution of six hydrated zinc nitrate and six methyl four amine by a chemical bath deposition method, through adding different amount of Al3+ in the seed layer, then ZnO nanorods were prepared. When the concentration of the seed layer solution was 0.1 M and the atomic percentage of Al3+ doping was 9%,the long side of FTO was put vertically into 0.04 M growth solution, the maximum length of nanorods can be up to 5 μm, the photoelectric properties of the corresponding DSSC was the best whose open circuit voltage was 0.4, short-circuit photocurrent was 5.64 mA/cm2, the fill factor was 0.47, the photoelectric conversion efficiency was 1.07%.(2)A special composite strcture kind of ZnO nanorods with ZnO nanoparticles were fabricated by impregmating seed layer and used as photoanode in DSSCs. When the ZnO seed layer doped with 9at% Al3+, and the times of dip coating reached 9 times and growth times is 9, the maximum length of the composite strcture ZnO nanorods with ZnO nanoparticles reached 15.2 μm. Its photoelectric conversion efficiency was 2.36%,Its open circuit voltage was 0.66 V, short-circuit photocurrent was 5.28 mA/cm2,the fill factor was 0.62.(3)The Al3+ doped ZnO nanoparticle were prepared by precipitation method,the Al doped ZnO nanosheet were prepared by ultrasonic assisted precipitation method,the Al3+ doped ZnO nanosphere were prepared by alcohol heating reflux method.These three kinds morphologies of the nanometer powers were prepared and used as photoanode and assembled into DSSCs under the same experomental conditions. The photoelectric conversion efficiency of the DSSCs assembled by 6at% Al3+-doped ZnO nanoparticles reached 0.94%;The photoelectric conversion efficiency of the DSSCs assembled by 6at% Al3+-doped ZnO nanosheet reached 0.73%;The photoelectric conversion efficiency of the DSSCs assembled by 6at% Al3+-doped ZnO nanosphere was 2.00%,which was 61.40% lower than undoped ZnO.