The Research And Application Of Cyclic Voltammetry In The Electrolyte For Quantum Dot Sensitized Solar Cells

In recent years, the quantum dot-sensitized solar cells have attracted extensive attention of the scientific researchers because the advantages of simple process, low cost, high efficiency, no pollution, etc. In this paper, our research focus on electrolytes, which is an important part of the quantum dot-sensitized solar cells. We developed an instructive method to evaluate the performance of quantum dot-sensitized solar cells containing different electrolytes using cyclic voltammetry, which has simplified the workload for the electrolyte study. And on the basis of these work, a kind of electrolyte which can improve the performance of quantum dot-sensitized solar cells was prepared.1. The effects of different sensitizers and electrode on the properties of the quantum dot-sensitized solar cells were studies respectively. We optimized the preparation process of quantum dot-sensitized solar cells, and obtained the best preparation conditions. It is concluded that the maximum photoelectric conversion efficiency of the solar cells prepared by using CdS/CdSe as the co-sensitization and PbSe as the electrode was achieved when the polysulfide electrolyte ((2 M Na2S,2 M S,0.2 M KCl in a methanol/water(7:3,v:v)) was used. The photoelectric conversion efficiency reached 4.7%.2. Different compositions and ratios of polysulfide electrolytes were prepared. Cyclic voltammetry were used to evaluate the electrolytes performance using a standard three-electrode system. The experimental results show that a higher reduction peak current in the cyclic voltammetry curve indicated a faster rate of the redox reaction (Sn2-to S2-) in the electrolyte. Meanwhile, photocurrent density vs. voltage curves were measured for assembled cells with different electrolytes. The resulting energy conversion efficiency measurements were consistent with the cyclic voltammetry results. Based on the Nyquist plot and the Bode phase plots of the electrolytes, we explained the reasons why such an electrolyte having high photoelectric conversion efficiency theoretically. In summary, we demonstrate direct connection between the photocurrent density in the quantum dot-sensitized solar cells and the catholic peak current measured by cyclic voltammetry using the same electrolyte. Therefore, the performance of the electrolyte can be judged by the cyclic voltammetry of the electrolyte and the study of electrolyte work could be simplified.3. In order to further improve the electrolyte performance, specific additive was added into the electrolyte, by using this intuitive approach, We built a quantum dot-sensitized solar cell with a power conversion efficiency of 5.14% on the CdS/CdSe co-sensitized TiO2 photoelectrode and PbSe counter electrode and polysulfide electrolyte consisting of 2 M Na2S,2 M S,0.2 M KCl in a methanol/water(7:3,v:v) with adding 0.05 M 1,2-dimethyl-3-propylimidazolium iodide in it.