Fabrication Of TiO₂-based Sensitized Solar Cells By Electrochemical Atomic Layer Deposition

Owning to the simple structure, high photoconversion efficiency and low cost, sensitized solar cells have attracted great attention of worldwide scientists. So far, various kinds of preparation method have been developed for the materials in the sensitized solar cells. But taken the factors such as film quality, operating feasibility and cost into consideration, there do exist many deficiencies. Electrochemical atomic layer deposition, which is based on under potential deposition, can be used to prepare compound films by alternated element deposition. It is facile to control the deposition process and can be conducted under ambient temperature with simple device. In this paper, electrochemical atomic layer deposition has been employed to prepare Co Se film on FTO and Ag Bi S2 quantum dot on Ti O2. Various tests and analyses have been carried out to characterize them.The electrochemical properties of Se and Co were studied by cycle voltammogram. The under potential deposition peak of Se spans in a wide potential range, while the electrochemical properties of Co exhibits a weak under potential deposition characteristics compared with the bulk deposition. Varying the potential of Se among its under potential deposition range and remaining the potential of Co unchanged, deposits with different morphologies and compositions have been achieved by electrochemical atomic layer deposition. XRD and XPS revealed that the deposits were amorphous Co Se with the ration of Co and Se varied with various condition of deposition. C ycle voltammogram and tafel curve were adopted to study the catalytic activity and stability of the deposits and Pt towards the iodine electrolyte. And the results show that different composition of cobalt selenide all display superior catalytic activity and stability than Pt. Furthermore, the film which the ratio of Co and Se of 1.2:1 exhibits the best catalytic activity and photoconversion performance when applied in dye sensitized solar cell, with a short circuit current density of 18.56 m A/cm2 and photoconversion efficiency of 9.28%?Cycle voltammogram was employed to investigate the electrochemical properties of S, Ag and Bi on the Ti O2 nanorods array film. The cycle voltammogram of S showed a weak under potential deposition characteristic, while both Ag and Bi manifested evident under potential deposition peaks. By optimizing the precursor solution and the deposition potential and time of every element, cubic Ag Bi S2 quantum dots were assembled onto Ti O2 nanorods film successfully by electrochemical atomic layer deposition. The quantum dots had a uniform size with good coverage. What's more, the quantum dots were homogeneously anchored on the top and cross section of Ti O 2 nanorods with no obvious aggregation and accumulation. Various cycles of quantum dots were deposited on the substrate. The optical absorbance of photoanode was enhanced to visible region and increased with the deposition time. When the quantum dots were deposited for 30 cycles, the quantum dot sensitized solar cell exhibited a best photoconversion efficiency of 0.95%.